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* Re: SetBufferCommitInfoNeedsSave and race conditions
@ 2007-07-05 07:46 Simon Riggs <[email protected]>
2007-07-05 08:05 ` Re: SetBufferCommitInfoNeedsSave and race conditions Gregory Stark <[email protected]>
0 siblings, 1 reply; 271+ messages in thread
From: Simon Riggs @ 2007-07-05 07:46 UTC (permalink / raw)
To: Tom Lane <[email protected]>; +Cc: Heikki Linnakangas <[email protected]>; Pavan Deolasee <[email protected]>; pgsql-hackers
On Thu, 2007-06-28 at 20:23 -0400, Tom Lane wrote:
> "Simon Riggs" <[email protected]> writes:
> > On Thu, 2007-06-28 at 15:16 -0400, Tom Lane wrote:
> >> A quick grep suggests that VACUUM FULL might be at risk here.
>
> > No we're clear: I caught that issue specifically for VACUUM FULL fairly
> > early on. VF assumes all hint bits are set after the first scan, so we
> > flush prior to the scan to ensure its safe to set the hint bits.
>
> Flush what prior to the scan?
>
> The methodology I suggested earlier (involving tracking LSN only at the
> level of pg_clog pages) isn't going to make that work, unless you
> somehow force the XID counter forward to the next page boundary.
> It might be that that level of tracking is too coarse anyway, since
> it essentially says that you can't hint any transaction until the
> next 32K-transaction boundary is reached.
Solutions I'm going for are these:
- Force XLogFlush() prior to initial VF scan. Tqual will set hint bits
if WAL has been flushed, else it will be deferred, so no WAL flushes
will be forced by normal hint bit setting and VF will work without
needing any crufty special cases or rework of VF logic.
- Use Tom's LSN tracking at clog page level. Make the LSN tracking store
an array of LSNs rather than just one. Array size is fixed at
NUMBER_TRACKED_LSNS_PER_PAGE, so that each LSN covers
32,000/NUMBER_TRACKED_LSNS_PER_PAGE transactions. I'd guess that storing
8 per page would be optimal, so each stored xid would track 4,000
transactions - probably around 1 sec worth of transactions when the
feature is used.
Comments?
--
Simon Riggs
EnterpriseDB http://www.enterprisedb.com
^ permalink raw reply [nested|flat] 271+ messages in thread
* Re: SetBufferCommitInfoNeedsSave and race conditions
2007-07-05 07:46 Re: SetBufferCommitInfoNeedsSave and race conditions Simon Riggs <[email protected]>
@ 2007-07-05 08:05 ` Gregory Stark <[email protected]>
2007-07-17 23:21 ` Re: SetBufferCommitInfoNeedsSave and race conditions Bruce Momjian <[email protected]>
0 siblings, 1 reply; 271+ messages in thread
From: Gregory Stark @ 2007-07-05 08:05 UTC (permalink / raw)
To: Simon Riggs <[email protected]>; +Cc: Tom Lane <[email protected]>; Heikki Linnakangas <[email protected]>; Pavan Deolasee <[email protected]>; pgsql-hackers
"Simon Riggs" <[email protected]> writes:
> I'd guess that storing 8 per page would be optimal, so each stored xid would
> track 4,000 transactions - probably around 1 sec worth of transactions when
> the feature is used.
This is something we can experiment with but I suspect that while 8 might be
sufficient for many use cases there would be others where more would be
better. The cost to having more lsns stored in the clog would be pretty small.
On TPCC which has longer transactions on moderate hardware we only see order
of 1,000 txn/min. So a setting like 128 which allows a granularity of 256
transactions would be about 15s which is not so much longer than the xmin
horizon of the 90th percentile response time of 2*5s.
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
^ permalink raw reply [nested|flat] 271+ messages in thread
* Re: SetBufferCommitInfoNeedsSave and race conditions
2007-07-05 07:46 Re: SetBufferCommitInfoNeedsSave and race conditions Simon Riggs <[email protected]>
2007-07-05 08:05 ` Re: SetBufferCommitInfoNeedsSave and race conditions Gregory Stark <[email protected]>
@ 2007-07-17 23:21 ` Bruce Momjian <[email protected]>
2007-07-18 00:01 ` Re: SetBufferCommitInfoNeedsSave and race conditions Gregory Stark <[email protected]>
0 siblings, 1 reply; 271+ messages in thread
From: Bruce Momjian @ 2007-07-17 23:21 UTC (permalink / raw)
To: Gregory Stark <[email protected]>; +Cc: Simon Riggs <[email protected]>; Tom Lane <[email protected]>; Heikki Linnakangas <[email protected]>; Pavan Deolasee <[email protected]>; pgsql-hackers
Where are we on this?
---------------------------------------------------------------------------
Gregory Stark wrote:
> "Simon Riggs" <[email protected]> writes:
>
> > I'd guess that storing 8 per page would be optimal, so each stored xid would
> > track 4,000 transactions - probably around 1 sec worth of transactions when
> > the feature is used.
>
> This is something we can experiment with but I suspect that while 8 might be
> sufficient for many use cases there would be others where more would be
> better. The cost to having more lsns stored in the clog would be pretty small.
>
> On TPCC which has longer transactions on moderate hardware we only see order
> of 1,000 txn/min. So a setting like 128 which allows a granularity of 256
> transactions would be about 15s which is not so much longer than the xmin
> horizon of the 90th percentile response time of 2*5s.
>
> --
> Gregory Stark
> EnterpriseDB http://www.enterprisedb.com
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Have you searched our list archives?
>
> http://archives.postgresql.org
--
Bruce Momjian <[email protected]> http://momjian.us
EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
^ permalink raw reply [nested|flat] 271+ messages in thread
* Re: SetBufferCommitInfoNeedsSave and race conditions
2007-07-05 07:46 Re: SetBufferCommitInfoNeedsSave and race conditions Simon Riggs <[email protected]>
2007-07-05 08:05 ` Re: SetBufferCommitInfoNeedsSave and race conditions Gregory Stark <[email protected]>
2007-07-17 23:21 ` Re: SetBufferCommitInfoNeedsSave and race conditions Bruce Momjian <[email protected]>
@ 2007-07-18 00:01 ` Gregory Stark <[email protected]>
2007-07-18 09:21 ` Re: SetBufferCommitInfoNeedsSave and race conditions Simon Riggs <[email protected]>
0 siblings, 1 reply; 271+ messages in thread
From: Gregory Stark @ 2007-07-18 00:01 UTC (permalink / raw)
To: Bruce Momjian <[email protected]>; +Cc: Simon Riggs <[email protected]>; Tom Lane <[email protected]>; Heikki Linnakangas <[email protected]>; Pavan Deolasee <[email protected]>; pgsql-hackers
"Bruce Momjian" <[email protected]> writes:
> Where are we on this?
Well Simon just sent the reworked patch yesterday so the answer is we haven't
started tuning this parameter. (Bruce's message is referring to the discussion
about what the optimal value of lsns per clog page would be.)
I intend to do some benchmarking on it and testing what the best value of this
parameter is one of the things I aim to determine with these benchmarks.
I'm not 100% sure yet what to measure though. There are two questions here:
1) What are some good workloads to test which will require larger values for
this parameter or which will be hurt by excessively large values?
I think any short-transaction workload should be basically good enough. I'm
thinking of using just pgbench's default workload. Does anyone think there are
other workloads that we need to specifically test?
2) What metric do I use to determine if the value is large enough or too
large?
The gross measurement would be to look at tps. I would prefer to actually
count events which we want to minimize such as xlogflushes because the clog
lsn is too old and how much extra work the visibility checks do. I'm not sure
exactly how much of this we can really measure though. Are there any other
events having an insufficiently large or excessively large value of this
parameter will cause which we can count?
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
^ permalink raw reply [nested|flat] 271+ messages in thread
* Re: SetBufferCommitInfoNeedsSave and race conditions
2007-07-05 07:46 Re: SetBufferCommitInfoNeedsSave and race conditions Simon Riggs <[email protected]>
2007-07-05 08:05 ` Re: SetBufferCommitInfoNeedsSave and race conditions Gregory Stark <[email protected]>
2007-07-17 23:21 ` Re: SetBufferCommitInfoNeedsSave and race conditions Bruce Momjian <[email protected]>
2007-07-18 00:01 ` Re: SetBufferCommitInfoNeedsSave and race conditions Gregory Stark <[email protected]>
@ 2007-07-18 09:21 ` Simon Riggs <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Simon Riggs @ 2007-07-18 09:21 UTC (permalink / raw)
To: Gregory Stark <[email protected]>; +Cc: Bruce Momjian <[email protected]>; Tom Lane <[email protected]>; Heikki Linnakangas <[email protected]>; Pavan Deolasee <[email protected]>; pgsql-hackers
On Wed, 2007-07-18 at 01:01 +0100, Gregory Stark wrote:
> "Bruce Momjian" <[email protected]> writes:
>
> > Where are we on this?
>
> Well Simon just sent the reworked patch yesterday so the answer is we haven't
> started tuning this parameter. (Bruce's message is referring to the discussion
> about what the optimal value of lsns per clog page would be.)
From discussion, Greg wishes to see a certain parameter higher, though
I'm fairly comfortable with the value now. Thanks to Greg for making me
think this through in more detail. There is some confirmation required,
but no significant tuning effort required.
Here's the thinking:
When we commit, we store an LSN that covers a group of transactions.
When we set hint bits we check the appropriate LSN. If it has been
flushed, then we set the hint bit.
If we're using synch commits then we can always set hint bits.
If we're mixing async commits with sync commits then the clog LSNs will
very often be flushed already, so we'll be able to set most hint bits.
If we are doing *only* simple async commits then only the WAL writer
flushes WAL. In that case when we try to set hint bits we will only be
prevented from setting hint bits for the last "few" transactions. So how
many is that exactly?
We are flushing WAL every W seconds and doing T transactions per second,
then we will flush WAL every T*W transactions. e.g. W = 0.2 (default), T
~ 10,000 => T*W = 2,000 transactions.
We have divided up each clog page up into N groups of transactions, each
with their own LSN, then we will have 32,000/N transactions per group.
The best situation is that we set N such that we never defer the setting
of a hint bit for a transaction that has been flushed.
There is no point setting N any lower than
32,000/N = T*W
i.e. N <= W * (32,000/T)
My laptop can do T=1000 with W=0.2 with pgbench, so N <= 6.
By definition, anyone using async commit will have a high transaction
rate (else there is no benefit), so N seems able to be reasonably small.
If the transaction rate drops off momentarily the number of unflushed
committed async transactions doesn't rise, it falls quickly to zero as
the WAL writer flushes WAL up to the last async LSN.
The patch sets a value of 16, which seems likely to be enough to cover
most situations.
Having thought that through, I see two changes I'd like to make:
- I realise that I've arranged the LSNs to be striped rather than
grouped. I'll change this part of the patch - couple of lines in
GetLSNIndex().
- The LSN of sync commits is also used to update the LSN of the clog
page. That is unnecessary and we only need set the clog LSN for async
commits.
I'll wait for other review comments before cutting version 23....
--
Simon Riggs
EnterpriseDB http://www.enterprisedb.com
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
* [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup.
@ 2024-05-18 01:41 Thomas Munro <[email protected]>
0 siblings, 0 replies; 271+ messages in thread
From: Thomas Munro @ 2024-05-18 01:41 UTC (permalink / raw)
When backend processes were launched in EXEC_BACKEND builds, they would
run LocalProcessControlFile() to read in pg_control and extract several
important settings.
This happens too early to acquire ControlFileLock, and the postmaster is
also not allowed to acquire ControlFileLock, so it can't safely take a
copy to give to the child.
Instead, pass down the "proto-controlfile" that was read by the
postmaster in LocalProcessControlFile(). Introduce functions
ExportProtoControlFile() and ImportProtoControlFile() to allow that.
Subprocesses will extract information from that, and then later attach
to the current control file in shared memory.
Reported-by: Melanie Plageman <[email protected]> per Windows CI failure
Discussion: https://postgr.es/m/CAAKRu_YNGwEYrorQYza_W8tU%2B%3DtoXRHG8HpyHC-KDbZqA_ZVSA%40mail.gmail.com
---
src/backend/access/transam/xlog.c | 46 +++++++++++++++++++++++--
src/backend/postmaster/launch_backend.c | 21 +++++++----
src/include/access/xlog.h | 5 +++
3 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13ec6225b85..e52517eb9c1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -575,6 +575,10 @@ static WALInsertLockPadded *WALInsertLocks = NULL;
*/
static ControlFileData *ControlFile = NULL;
+#ifdef EXEC_BACKEND
+static ControlFileData *ProtoControlFile = NULL;
+#endif
+
/*
* Calculate the amount of space left on the page after 'endptr'. Beware
* multiple evaluation!
@@ -692,6 +696,7 @@ static bool PerformRecoveryXLogAction(void);
static void InitControlFile(uint64 sysidentifier, uint32 data_checksum_version);
static void WriteControlFile(void);
static void ReadControlFile(void);
+static void ScanControlFile(void);
static void UpdateControlFile(void);
static char *str_time(pg_time_t tnow, char *buf, size_t bufsize);
@@ -4385,9 +4390,7 @@ WriteControlFile(void)
static void
ReadControlFile(void)
{
- pg_crc32c crc;
int fd;
- char wal_segsz_str[20];
int r;
/*
@@ -4420,6 +4423,15 @@ ReadControlFile(void)
close(fd);
+ ScanControlFile();
+}
+
+static void
+ScanControlFile(void)
+{
+ static char wal_segsz_str[20];
+ pg_crc32c crc;
+
/*
* Check for expected pg_control format version. If this is wrong, the
* CRC check will likely fail because we'll be checking the wrong number
@@ -4941,8 +4953,33 @@ LocalProcessControlFile(bool reset)
Assert(reset || ControlFile == NULL);
ControlFile = palloc_object(ControlFileData);
ReadControlFile();
+
+#ifdef EXEC_BACKEND
+ /* We need to be able to give this to subprocesses. */
+ ProtoControlFile = ControlFile;
+#endif
}
+#ifdef EXEC_BACKEND
+void
+ExportProtoControlFile(ControlFileData *copy)
+{
+ *copy = *ProtoControlFile;
+}
+
+/*
+ * Like LocalProcessControlFile(), but used early in EXEC_BACKEND children's
+ * startup. This receives the same file that the postmaster first read.
+ */
+void
+ImportProtoControlFile(const ControlFileData *copy)
+{
+ ControlFile = palloc(sizeof(ControlFileData));
+ *ControlFile = *copy;
+ ScanControlFile();
+}
+#endif
+
/*
* Get the wal_level from the control file. For a standby, this value should be
* considered as its active wal_level, because it may be different from what
@@ -5061,7 +5098,12 @@ XLOGShmemInit(void)
if (localControlFile)
{
memcpy(ControlFile, localControlFile, sizeof(ControlFileData));
+#ifdef EXEC_BACKEND
+ /* We still hold a reference to give to subprocesses. */
+ Assert(ProtoControlFile == localControlFile);
+#else
pfree(localControlFile);
+#endif
}
/*
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 45690b11c99..e08a405f949 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -33,6 +33,9 @@
#include <unistd.h>
+#include "access/xlog.h"
+#include "catalog/pg_control.h"
+#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
@@ -133,6 +136,14 @@ typedef struct
int MyPMChildSlot;
+ /*
+ * A copy of the ControlFileData from early in Postmaster startup. We
+ * need to access its contents it at a phase of initialization before we
+ * are allowed to acquire LWLocks, so we can't just use shared memory or
+ * read the file from disk.
+ */
+ ControlFileData proto_controlfile;
+
/*
* These are only used by backend processes, but are here because passing
* a socket needs some special handling on Windows. 'client_sock' is an
@@ -659,12 +670,6 @@ SubPostmasterMain(int argc, char *argv[])
*/
checkDataDir();
- /*
- * (re-)read control file, as it contains config. The postmaster will
- * already have read this, but this process doesn't know about that.
- */
- LocalProcessControlFile(false);
-
/*
* Reload any libraries that were preloaded by the postmaster. Since we
* exec'd this process, those libraries didn't come along with us; but we
@@ -752,6 +757,8 @@ save_backend_variables(BackendParameters *param,
param->MaxBackends = MaxBackends;
param->num_pmchild_slots = num_pmchild_slots;
+ ExportProtoControlFile(¶m->proto_controlfile);
+
#ifdef WIN32
param->PostmasterHandle = PostmasterHandle;
if (!write_duplicated_handle(¶m->initial_signal_pipe,
@@ -1026,6 +1033,8 @@ restore_backend_variables(BackendParameters *param)
strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
+ ImportProtoControlFile(¶m->proto_controlfile);
+
/*
* We need to restore fd.c's counts of externally-opened FDs; to avoid
* confusion, be sure to do this after restoring max_safe_fds. (Note:
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index fdfb572467b..f1f3ad4e96e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -208,6 +208,7 @@ typedef enum WALAvailability
struct XLogRecData;
struct XLogReaderState;
+struct ControlFileData;
extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
XLogRecPtr fpw_lsn,
@@ -250,6 +251,10 @@ extern void XLOGShmemInit(void);
extern void BootStrapXLOG(uint32 data_checksum_version);
extern void InitializeWalConsistencyChecking(void);
extern void LocalProcessControlFile(bool reset);
+#ifdef EXEC_BACKEND
+extern void ExportProtoControlFile(struct ControlFileData *copy);
+extern void ImportProtoControlFile(const struct ControlFileData *copy);
+#endif
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
--
2.47.3
--dhbc6bswyy6qufwn--
^ permalink raw reply [nested|flat] 271+ messages in thread
end of thread, other threads:[~2024-05-18 01:41 UTC | newest]
Thread overview: 271+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2007-07-05 07:46 Re: SetBufferCommitInfoNeedsSave and race conditions Simon Riggs <[email protected]>
2007-07-05 08:05 ` Gregory Stark <[email protected]>
2007-07-17 23:21 ` Bruce Momjian <[email protected]>
2007-07-18 00:01 ` Gregory Stark <[email protected]>
2007-07-18 09:21 ` Simon Riggs <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
2024-05-18 01:41 [PATCH v2] Fix pg_control corruption in EXEC_BACKEND startup. Thomas Munro <[email protected]>
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