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* Re: [PATCH] Refactor SLRU to always use long file names
@ 2025-01-15 12:42 Aleksander Alekseev <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Aleksander Alekseev @ 2025-01-15 12:42 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>; +Cc: Michael Paquier <[email protected]>
Hi,
> Here is an updated patch. The steps to test it manually are as follows.
>
> Compile and install PostgreSQL from the REL_17_STABLE branch:
>
> [...]
>
> As always, your feedback and suggestions are most welcomed.
Rebased.
--
Best regards,
Aleksander Alekseev
Attachments:
[application/octet-stream] v3-0001-Always-use-long-SLRU-segment-file-names.patch (14.9K, 2-v3-0001-Always-use-long-SLRU-segment-file-names.patch)
download | inline diff:
From 28e1dc9564256f2befe991dc9e89390f0f0f5c7c Mon Sep 17 00:00:00 2001
From: Aleksander Alekseev <[email protected]>
Date: Wed, 11 Sep 2024 13:17:33 +0300
Subject: [PATCH v3] Always use long SLRU segment file names
PG17 introduced long SLRU segment file names (commit 4ed8f0913bfd). We used
short or long file names depending on SlruCtl->long_segment_names. This commit
refactors SLRU to always use long file names in order to simplify the code.
Aleksander Alekseev, reviewed by Michael Paquier
Discussion: https://postgr.es/m/CAJ7c6TOy7fUW9MuNeOWor3cSFnQg9tgz=mjXHDb94GORtM_Eyg@mail.gmail.com
(!!!) bump catversion and change the corresponding TODO FIXME line in pg_upgrade.h
---
src/backend/access/transam/clog.c | 2 +-
src/backend/access/transam/commit_ts.c | 3 +-
src/backend/access/transam/multixact.c | 6 +-
src/backend/access/transam/slru.c | 73 ++++----------------
src/backend/access/transam/subtrans.c | 2 +-
src/backend/commands/async.c | 2 +-
src/backend/storage/lmgr/predicate.c | 2 +-
src/bin/pg_upgrade/pg_upgrade.c | 74 +++++++++++++++++++++
src/bin/pg_upgrade/pg_upgrade.h | 6 ++
src/bin/pg_verifybackup/t/003_corruption.pl | 2 +-
src/include/access/slru.h | 10 +--
src/test/modules/test_slru/test_slru.c | 8 +--
12 files changed, 104 insertions(+), 86 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 0d556c00b8c..7a238efc227 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -810,7 +810,7 @@ CLOGShmemInit(void)
XactCtl->PagePrecedes = CLOGPagePrecedes;
SimpleLruInit(XactCtl, "transaction", CLOGShmemBuffers(), CLOG_LSNS_PER_PAGE,
"pg_xact", LWTRANCHE_XACT_BUFFER,
- LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG, false);
+ LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG);
SlruPagePrecedesUnitTests(XactCtl, CLOG_XACTS_PER_PAGE);
}
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 95049acd0b5..99252cd9b87 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -556,8 +556,7 @@ CommitTsShmemInit(void)
SimpleLruInit(CommitTsCtl, "commit_timestamp", CommitTsShmemBuffers(), 0,
"pg_commit_ts", LWTRANCHE_COMMITTS_BUFFER,
LWTRANCHE_COMMITTS_SLRU,
- SYNC_HANDLER_COMMIT_TS,
- false);
+ SYNC_HANDLER_COMMIT_TS);
SlruPagePrecedesUnitTests(CommitTsCtl, COMMIT_TS_XACTS_PER_PAGE);
commitTsShared = ShmemInitStruct("CommitTs shared",
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 27ccdf9500f..2cc64289054 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1974,15 +1974,13 @@ MultiXactShmemInit(void)
"multixact_offset", multixact_offset_buffers, 0,
"pg_multixact/offsets", LWTRANCHE_MULTIXACTOFFSET_BUFFER,
LWTRANCHE_MULTIXACTOFFSET_SLRU,
- SYNC_HANDLER_MULTIXACT_OFFSET,
- false);
+ SYNC_HANDLER_MULTIXACT_OFFSET);
SlruPagePrecedesUnitTests(MultiXactOffsetCtl, MULTIXACT_OFFSETS_PER_PAGE);
SimpleLruInit(MultiXactMemberCtl,
"multixact_member", multixact_member_buffers, 0,
"pg_multixact/members", LWTRANCHE_MULTIXACTMEMBER_BUFFER,
LWTRANCHE_MULTIXACTMEMBER_SLRU,
- SYNC_HANDLER_MULTIXACT_MEMBER,
- false);
+ SYNC_HANDLER_MULTIXACT_MEMBER);
/* doesn't call SimpleLruTruncate() or meet criteria for unit tests */
/* Initialize our shared state struct */
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 9ce628e62a5..cc078d2e6ce 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -77,42 +77,22 @@
*
* "path" should point to a buffer at least MAXPGPATH characters long.
*
- * If ctl->long_segment_names is true, segno can be in the range [0, 2^60-1].
- * The resulting file name is made of 15 characters, e.g. dir/123456789ABCDEF.
- *
- * If ctl->long_segment_names is false, segno can be in the range [0, 2^24-1].
- * The resulting file name is made of 4 to 6 characters, as of:
- *
- * dir/1234 for [0, 2^16-1]
- * dir/12345 for [2^16, 2^20-1]
- * dir/123456 for [2^20, 2^24-1]
+ * segno can be in the range [0, 2^60-1]. The resulting file name is made
+ * of 15 characters, e.g. dir/123456789ABCDEF.
*/
static inline int
SlruFileName(SlruCtl ctl, char *path, int64 segno)
{
- if (ctl->long_segment_names)
- {
- /*
- * We could use 16 characters here but the disadvantage would be that
- * the SLRU segments will be hard to distinguish from WAL segments.
- *
- * For this reason we use 15 characters. It is enough but also means
- * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%015llX", ctl->Dir,
- (long long) segno);
- }
- else
- {
- /*
- * Despite the fact that %04X format string is used up to 24 bit
- * integers are allowed. See SlruCorrectSegmentFilenameLength()
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir,
- (unsigned int) segno);
- }
+ /*
+ * We could use 16 characters here but the disadvantage would be that
+ * the SLRU segments will be hard to distinguish from WAL segments.
+ *
+ * For this reason we use 15 characters. It is enough but also means
+ * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
+ */
+ Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
+ return snprintf(path, MAXPGPATH, "%s/%015llX", ctl->Dir,
+ (long long) segno);
}
/*
@@ -251,7 +231,7 @@ SimpleLruAutotuneBuffers(int divisor, int max)
void
SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id, int bank_tranche_id,
- SyncRequestHandler sync_handler, bool long_segment_names)
+ SyncRequestHandler sync_handler)
{
SlruShared shared;
bool found;
@@ -342,7 +322,6 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
*/
ctl->shared = shared;
ctl->sync_handler = sync_handler;
- ctl->long_segment_names = long_segment_names;
ctl->nbanks = nbanks;
strlcpy(ctl->Dir, subdir, sizeof(ctl->Dir));
}
@@ -1748,30 +1727,6 @@ SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage, void *data)
return false; /* keep going */
}
-/*
- * An internal function used by SlruScanDirectory().
- *
- * Returns true if a file with a name of a given length may be a correct
- * SLRU segment.
- */
-static inline bool
-SlruCorrectSegmentFilenameLength(SlruCtl ctl, size_t len)
-{
- if (ctl->long_segment_names)
- return (len == 15); /* see SlruFileName() */
- else
-
- /*
- * Commit 638cf09e76d allowed 5-character lengths. Later commit
- * 73c986adde5 allowed 6-character length.
- *
- * Note: There is an ongoing plan to migrate all SLRUs to 64-bit page
- * numbers, and the corresponding 15-character file names, which may
- * eventually deprecate the support for 4, 5, and 6-character names.
- */
- return (len == 4 || len == 5 || len == 6);
-}
-
/*
* Scan the SimpleLru directory and apply a callback to each file found in it.
*
@@ -1803,7 +1758,7 @@ SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data)
len = strlen(clde->d_name);
- if (SlruCorrectSegmentFilenameLength(ctl, len) &&
+ if ((len == 15) &&
strspn(clde->d_name, "0123456789ABCDEF") == len)
{
segno = strtoi64(clde->d_name, NULL, 16);
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index 15153618fad..58a5ef657ea 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -243,7 +243,7 @@ SUBTRANSShmemInit(void)
SubTransCtl->PagePrecedes = SubTransPagePrecedes;
SimpleLruInit(SubTransCtl, "subtransaction", SUBTRANSShmemBuffers(), 0,
"pg_subtrans", LWTRANCHE_SUBTRANS_BUFFER,
- LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE, false);
+ LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE);
SlruPagePrecedesUnitTests(SubTransCtl, SUBTRANS_XACTS_PER_PAGE);
}
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 4bd37d5beb5..373b0357fad 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -537,7 +537,7 @@ AsyncShmemInit(void)
NotifyCtl->PagePrecedes = asyncQueuePagePrecedes;
SimpleLruInit(NotifyCtl, "notify", notify_buffers, 0,
"pg_notify", LWTRANCHE_NOTIFY_BUFFER, LWTRANCHE_NOTIFY_SLRU,
- SYNC_HANDLER_NONE, true);
+ SYNC_HANDLER_NONE);
if (!found)
{
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index 5b21a053981..bc83e8e859d 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -814,7 +814,7 @@ SerialInit(void)
SimpleLruInit(SerialSlruCtl, "serializable",
serializable_buffers, 0, "pg_serial",
LWTRANCHE_SERIAL_BUFFER, LWTRANCHE_SERIAL_SLRU,
- SYNC_HANDLER_NONE, false);
+ SYNC_HANDLER_NONE);
#ifdef USE_ASSERT_CHECKING
SerialPagePrecedesLogicallyUnitTests();
#endif
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index 36c7f3879d5..6d3dcc63d2b 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -38,6 +38,7 @@
#include "postgres_fe.h"
+#include <dirent.h>
#include <time.h>
#include "catalog/pg_class_d.h"
@@ -59,6 +60,8 @@ static void prepare_new_cluster(void);
static void prepare_new_globals(void);
static void create_new_objects(void);
static void copy_xact_xlog_xid(void);
+static void check_slru_segment_filenames(void);
+static void rename_slru_segments(const char *dirname);
static void set_frozenxids(bool minmxid_only);
static void make_outputdirs(char *pgdata);
static void setup(char *argv0);
@@ -154,6 +157,7 @@ main(int argc, char **argv)
*/
copy_xact_xlog_xid();
+ check_slru_segment_filenames();
/* New now using xids of the old system */
@@ -806,6 +810,76 @@ copy_xact_xlog_xid(void)
check_ok();
}
+static void
+rename_slru_segments(const char* dirname)
+{
+ DIR *dir;
+ struct dirent *de;
+ int len;
+ int64 segno;
+ char dir_path[MAXPGPATH];
+ char old_path[MAXPGPATH];
+ char new_path[MAXPGPATH];
+
+ prep_status("Renaming SLRU segments in %s", dirname);
+ snprintf(dir_path, sizeof(dir_path), "%s/%s", new_cluster.pgdata, dirname);
+
+ dir = opendir(dir_path);
+ if (dir == NULL)
+ pg_fatal("could not open directory \"%s\": %m", dir_path);
+
+ while (errno = 0, (de = readdir(dir)) != NULL)
+ {
+ /*
+ * ignore '.', '..' and everything else that doesn't look
+ * like an SLRU segment with a short file name
+ */
+
+ len = strlen(de->d_name);
+ if(len != 4 && len != 5 && len != 6)
+ continue;
+
+ if(strspn(de->d_name, "0123456789ABCDEF") != len)
+ continue;
+
+ segno = strtoi64(de->d_name, NULL, 16);
+ snprintf(new_path, MAXPGPATH, "%s/%015llX", dir_path,
+ (long long) segno);
+ snprintf(old_path, MAXPGPATH, "%s/%s", dir_path, de->d_name);
+
+ if (pg_mv_file(old_path, new_path) != 0)
+ pg_fatal("could not rename file \"%s\" to \"%s\": %m",
+ old_path, new_path);
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %m", dir_path);
+
+ if (closedir(dir))
+ pg_fatal("could not close directory \"%s\": %m", dir_path);
+
+ check_ok();
+}
+
+static void
+check_slru_segment_filenames(void)
+{
+ int i;
+ static const char* dirs[] = {
+ "pg_xact",
+ "pg_commit_ts",
+ "pg_multixact/offsets",
+ "pg_multixact/members",
+ "pg_subtrans",
+ "pg_serial",
+ };
+
+ if(old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
+ return;
+
+ for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); i++)
+ rename_slru_segments(dirs[i]);
+}
/*
* set_frozenxids()
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 0cdd675e4f1..a839f19e310 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -125,6 +125,12 @@ extern char *output_files[];
*/
#define JSONB_FORMAT_CHANGE_CAT_VER 201409291
+/*
+ * change of SLRU segment filenames length in 18.0
+ * TODO FIXME CHANGE TO THE ACTUAL VALUE BEFORE COMMITTING
+ */
+#define SLRU_SEG_FILENAMES_CHANGE_CAT_VER 202412201
+
/*
* Each relation is represented by a relinfo structure.
diff --git a/src/bin/pg_verifybackup/t/003_corruption.pl b/src/bin/pg_verifybackup/t/003_corruption.pl
index 1111b09637d..9d1dbb93d72 100644
--- a/src/bin/pg_verifybackup/t/003_corruption.pl
+++ b/src/bin/pg_verifybackup/t/003_corruption.pl
@@ -237,7 +237,7 @@ sub mutilate_extra_tablespace_file
sub mutilate_missing_file
{
my ($backup_path) = @_;
- my $pathname = "$backup_path/pg_xact/0000";
+ my $pathname = "$backup_path/pg_xact/000000000000000";
unlink($pathname) || die "$pathname: $!";
return;
}
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index e142800aab2..ecf2ca79692 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -131,13 +131,6 @@ typedef struct SlruCtlData
/* Number of banks in this SLRU. */
uint16 nbanks;
- /*
- * If true, use long segment file names. Otherwise, use short file names.
- *
- * For details about the file name format, see SlruFileName().
- */
- bool long_segment_names;
-
/*
* Which sync handler function to use when handing sync requests over to
* the checkpointer. SYNC_HANDLER_NONE to disable fsync (eg pg_notify).
@@ -184,8 +177,7 @@ extern Size SimpleLruShmemSize(int nslots, int nlsns);
extern int SimpleLruAutotuneBuffers(int divisor, int max);
extern void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id,
- int bank_tranche_id, SyncRequestHandler sync_handler,
- bool long_segment_names);
+ int bank_tranche_id, SyncRequestHandler sync_handler);
extern int SimpleLruZeroPage(SlruCtl ctl, int64 pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int64 pageno, bool write_ok,
TransactionId xid);
diff --git a/src/test/modules/test_slru/test_slru.c b/src/test/modules/test_slru/test_slru.c
index 3ea5ceb8552..cbd5173015a 100644
--- a/src/test/modules/test_slru/test_slru.c
+++ b/src/test/modules/test_slru/test_slru.c
@@ -213,11 +213,6 @@ test_slru_page_precedes_logically(int64 page1, int64 page2)
static void
test_slru_shmem_startup(void)
{
- /*
- * Short segments names are well tested elsewhere so in this test we are
- * focusing on long names.
- */
- const bool long_segment_names = true;
const char slru_dir_name[] = "pg_test_slru";
int test_tranche_id;
int test_buffer_tranche_id;
@@ -241,8 +236,7 @@ test_slru_shmem_startup(void)
TestSlruCtl->PagePrecedes = test_slru_page_precedes_logically;
SimpleLruInit(TestSlruCtl, "TestSLRU",
NUM_TEST_BUFFERS, 0, slru_dir_name,
- test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE,
- long_segment_names);
+ test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE);
}
void
--
2.47.1
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2025-02-25 14:18 Aleksander Alekseev <[email protected]>
parent: Aleksander Alekseev <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Aleksander Alekseev @ 2025-02-25 14:18 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>; +Cc: Michael Paquier <[email protected]>
Hi,
> > Here is an updated patch. The steps to test it manually are as follows.
> >
> > Compile and install PostgreSQL from the REL_17_STABLE branch:
> >
> > [...]
> >
> > As always, your feedback and suggestions are most welcomed.
>
> Rebased.
Rebased.
--
Best regards,
Aleksander Alekseev
Attachments:
[application/x-patch] v4-0001-Always-use-long-SLRU-segment-file-names.patch (14.9K, 2-v4-0001-Always-use-long-SLRU-segment-file-names.patch)
download | inline diff:
From 43e7cdccf1aa96e6522a41518bf0437dda23cc4d Mon Sep 17 00:00:00 2001
From: Aleksander Alekseev <[email protected]>
Date: Wed, 11 Sep 2024 13:17:33 +0300
Subject: [PATCH v4] Always use long SLRU segment file names
PG17 introduced long SLRU segment file names (commit 4ed8f0913bfd). We used
short or long file names depending on SlruCtl->long_segment_names. This commit
refactors SLRU to always use long file names in order to simplify the code.
Aleksander Alekseev, reviewed by Michael Paquier
Discussion: https://postgr.es/m/CAJ7c6TOy7fUW9MuNeOWor3cSFnQg9tgz=mjXHDb94GORtM_Eyg@mail.gmail.com
(!!!) bump catversion and change the corresponding TODO FIXME line in pg_upgrade.h
---
src/backend/access/transam/clog.c | 2 +-
src/backend/access/transam/commit_ts.c | 3 +-
src/backend/access/transam/multixact.c | 6 +-
src/backend/access/transam/slru.c | 73 ++++----------------
src/backend/access/transam/subtrans.c | 2 +-
src/backend/commands/async.c | 2 +-
src/backend/storage/lmgr/predicate.c | 2 +-
src/bin/pg_upgrade/pg_upgrade.c | 74 +++++++++++++++++++++
src/bin/pg_upgrade/pg_upgrade.h | 6 ++
src/bin/pg_verifybackup/t/003_corruption.pl | 2 +-
src/include/access/slru.h | 10 +--
src/test/modules/test_slru/test_slru.c | 8 +--
12 files changed, 104 insertions(+), 86 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 48f10bec91e..f130403ac4b 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -810,7 +810,7 @@ CLOGShmemInit(void)
XactCtl->PagePrecedes = CLOGPagePrecedes;
SimpleLruInit(XactCtl, "transaction", CLOGShmemBuffers(), CLOG_LSNS_PER_PAGE,
"pg_xact", LWTRANCHE_XACT_BUFFER,
- LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG, false);
+ LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG);
SlruPagePrecedesUnitTests(XactCtl, CLOG_XACTS_PER_PAGE);
}
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 113fae1437a..59535526823 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -556,8 +556,7 @@ CommitTsShmemInit(void)
SimpleLruInit(CommitTsCtl, "commit_timestamp", CommitTsShmemBuffers(), 0,
"pg_commit_ts", LWTRANCHE_COMMITTS_BUFFER,
LWTRANCHE_COMMITTS_SLRU,
- SYNC_HANDLER_COMMIT_TS,
- false);
+ SYNC_HANDLER_COMMIT_TS);
SlruPagePrecedesUnitTests(CommitTsCtl, COMMIT_TS_XACTS_PER_PAGE);
commitTsShared = ShmemInitStruct("CommitTs shared",
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index c1e2c42e1bb..b3b11c1a0ad 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1974,15 +1974,13 @@ MultiXactShmemInit(void)
"multixact_offset", multixact_offset_buffers, 0,
"pg_multixact/offsets", LWTRANCHE_MULTIXACTOFFSET_BUFFER,
LWTRANCHE_MULTIXACTOFFSET_SLRU,
- SYNC_HANDLER_MULTIXACT_OFFSET,
- false);
+ SYNC_HANDLER_MULTIXACT_OFFSET);
SlruPagePrecedesUnitTests(MultiXactOffsetCtl, MULTIXACT_OFFSETS_PER_PAGE);
SimpleLruInit(MultiXactMemberCtl,
"multixact_member", multixact_member_buffers, 0,
"pg_multixact/members", LWTRANCHE_MULTIXACTMEMBER_BUFFER,
LWTRANCHE_MULTIXACTMEMBER_SLRU,
- SYNC_HANDLER_MULTIXACT_MEMBER,
- false);
+ SYNC_HANDLER_MULTIXACT_MEMBER);
/* doesn't call SimpleLruTruncate() or meet criteria for unit tests */
/* Initialize our shared state struct */
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 9ce628e62a5..cc078d2e6ce 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -77,42 +77,22 @@
*
* "path" should point to a buffer at least MAXPGPATH characters long.
*
- * If ctl->long_segment_names is true, segno can be in the range [0, 2^60-1].
- * The resulting file name is made of 15 characters, e.g. dir/123456789ABCDEF.
- *
- * If ctl->long_segment_names is false, segno can be in the range [0, 2^24-1].
- * The resulting file name is made of 4 to 6 characters, as of:
- *
- * dir/1234 for [0, 2^16-1]
- * dir/12345 for [2^16, 2^20-1]
- * dir/123456 for [2^20, 2^24-1]
+ * segno can be in the range [0, 2^60-1]. The resulting file name is made
+ * of 15 characters, e.g. dir/123456789ABCDEF.
*/
static inline int
SlruFileName(SlruCtl ctl, char *path, int64 segno)
{
- if (ctl->long_segment_names)
- {
- /*
- * We could use 16 characters here but the disadvantage would be that
- * the SLRU segments will be hard to distinguish from WAL segments.
- *
- * For this reason we use 15 characters. It is enough but also means
- * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%015llX", ctl->Dir,
- (long long) segno);
- }
- else
- {
- /*
- * Despite the fact that %04X format string is used up to 24 bit
- * integers are allowed. See SlruCorrectSegmentFilenameLength()
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir,
- (unsigned int) segno);
- }
+ /*
+ * We could use 16 characters here but the disadvantage would be that
+ * the SLRU segments will be hard to distinguish from WAL segments.
+ *
+ * For this reason we use 15 characters. It is enough but also means
+ * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
+ */
+ Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
+ return snprintf(path, MAXPGPATH, "%s/%015llX", ctl->Dir,
+ (long long) segno);
}
/*
@@ -251,7 +231,7 @@ SimpleLruAutotuneBuffers(int divisor, int max)
void
SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id, int bank_tranche_id,
- SyncRequestHandler sync_handler, bool long_segment_names)
+ SyncRequestHandler sync_handler)
{
SlruShared shared;
bool found;
@@ -342,7 +322,6 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
*/
ctl->shared = shared;
ctl->sync_handler = sync_handler;
- ctl->long_segment_names = long_segment_names;
ctl->nbanks = nbanks;
strlcpy(ctl->Dir, subdir, sizeof(ctl->Dir));
}
@@ -1748,30 +1727,6 @@ SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage, void *data)
return false; /* keep going */
}
-/*
- * An internal function used by SlruScanDirectory().
- *
- * Returns true if a file with a name of a given length may be a correct
- * SLRU segment.
- */
-static inline bool
-SlruCorrectSegmentFilenameLength(SlruCtl ctl, size_t len)
-{
- if (ctl->long_segment_names)
- return (len == 15); /* see SlruFileName() */
- else
-
- /*
- * Commit 638cf09e76d allowed 5-character lengths. Later commit
- * 73c986adde5 allowed 6-character length.
- *
- * Note: There is an ongoing plan to migrate all SLRUs to 64-bit page
- * numbers, and the corresponding 15-character file names, which may
- * eventually deprecate the support for 4, 5, and 6-character names.
- */
- return (len == 4 || len == 5 || len == 6);
-}
-
/*
* Scan the SimpleLru directory and apply a callback to each file found in it.
*
@@ -1803,7 +1758,7 @@ SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data)
len = strlen(clde->d_name);
- if (SlruCorrectSegmentFilenameLength(ctl, len) &&
+ if ((len == 15) &&
strspn(clde->d_name, "0123456789ABCDEF") == len)
{
segno = strtoi64(clde->d_name, NULL, 16);
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index 15153618fad..58a5ef657ea 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -243,7 +243,7 @@ SUBTRANSShmemInit(void)
SubTransCtl->PagePrecedes = SubTransPagePrecedes;
SimpleLruInit(SubTransCtl, "subtransaction", SUBTRANSShmemBuffers(), 0,
"pg_subtrans", LWTRANCHE_SUBTRANS_BUFFER,
- LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE, false);
+ LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE);
SlruPagePrecedesUnitTests(SubTransCtl, SUBTRANS_XACTS_PER_PAGE);
}
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 4bd37d5beb5..373b0357fad 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -537,7 +537,7 @@ AsyncShmemInit(void)
NotifyCtl->PagePrecedes = asyncQueuePagePrecedes;
SimpleLruInit(NotifyCtl, "notify", notify_buffers, 0,
"pg_notify", LWTRANCHE_NOTIFY_BUFFER, LWTRANCHE_NOTIFY_SLRU,
- SYNC_HANDLER_NONE, true);
+ SYNC_HANDLER_NONE);
if (!found)
{
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index 5b21a053981..bc83e8e859d 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -814,7 +814,7 @@ SerialInit(void)
SimpleLruInit(SerialSlruCtl, "serializable",
serializable_buffers, 0, "pg_serial",
LWTRANCHE_SERIAL_BUFFER, LWTRANCHE_SERIAL_SLRU,
- SYNC_HANDLER_NONE, false);
+ SYNC_HANDLER_NONE);
#ifdef USE_ASSERT_CHECKING
SerialPagePrecedesLogicallyUnitTests();
#endif
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index d95c491fb57..8b10908e1f2 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -38,6 +38,7 @@
#include "postgres_fe.h"
+#include <dirent.h>
#include <time.h>
#include "catalog/pg_class_d.h"
@@ -60,6 +61,8 @@ static void prepare_new_cluster(void);
static void prepare_new_globals(void);
static void create_new_objects(void);
static void copy_xact_xlog_xid(void);
+static void check_slru_segment_filenames(void);
+static void rename_slru_segments(const char *dirname);
static void set_frozenxids(bool minmxid_only);
static void make_outputdirs(char *pgdata);
static void setup(char *argv0);
@@ -156,6 +159,7 @@ main(int argc, char **argv)
copy_xact_xlog_xid();
set_new_cluster_char_signedness();
+ check_slru_segment_filenames();
/* New now using xids of the old system */
@@ -840,6 +844,76 @@ copy_xact_xlog_xid(void)
check_ok();
}
+static void
+rename_slru_segments(const char* dirname)
+{
+ DIR *dir;
+ struct dirent *de;
+ int len;
+ int64 segno;
+ char dir_path[MAXPGPATH];
+ char old_path[MAXPGPATH];
+ char new_path[MAXPGPATH];
+
+ prep_status("Renaming SLRU segments in %s", dirname);
+ snprintf(dir_path, sizeof(dir_path), "%s/%s", new_cluster.pgdata, dirname);
+
+ dir = opendir(dir_path);
+ if (dir == NULL)
+ pg_fatal("could not open directory \"%s\": %m", dir_path);
+
+ while (errno = 0, (de = readdir(dir)) != NULL)
+ {
+ /*
+ * ignore '.', '..' and everything else that doesn't look
+ * like an SLRU segment with a short file name
+ */
+
+ len = strlen(de->d_name);
+ if(len != 4 && len != 5 && len != 6)
+ continue;
+
+ if(strspn(de->d_name, "0123456789ABCDEF") != len)
+ continue;
+
+ segno = strtoi64(de->d_name, NULL, 16);
+ snprintf(new_path, MAXPGPATH, "%s/%015llX", dir_path,
+ (long long) segno);
+ snprintf(old_path, MAXPGPATH, "%s/%s", dir_path, de->d_name);
+
+ if (pg_mv_file(old_path, new_path) != 0)
+ pg_fatal("could not rename file \"%s\" to \"%s\": %m",
+ old_path, new_path);
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %m", dir_path);
+
+ if (closedir(dir))
+ pg_fatal("could not close directory \"%s\": %m", dir_path);
+
+ check_ok();
+}
+
+static void
+check_slru_segment_filenames(void)
+{
+ int i;
+ static const char* dirs[] = {
+ "pg_xact",
+ "pg_commit_ts",
+ "pg_multixact/offsets",
+ "pg_multixact/members",
+ "pg_subtrans",
+ "pg_serial",
+ };
+
+ if(old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
+ return;
+
+ for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); i++)
+ rename_slru_segments(dirs[i]);
+}
/*
* set_frozenxids()
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index f4e375d27c7..0340a20a391 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -131,6 +131,12 @@ extern char *output_files[];
*/
#define DEFAULT_CHAR_SIGNEDNESS_CAT_VER 202502212
+/*
+ * change of SLRU segment filenames length in 18.0
+ * TODO FIXME CHANGE TO THE ACTUAL VALUE BEFORE COMMITTING
+ */
+#define SLRU_SEG_FILENAMES_CHANGE_CAT_VER 202412201
+
/*
* Each relation is represented by a relinfo structure.
*/
diff --git a/src/bin/pg_verifybackup/t/003_corruption.pl b/src/bin/pg_verifybackup/t/003_corruption.pl
index 8ef7f8a4e7a..367212af529 100644
--- a/src/bin/pg_verifybackup/t/003_corruption.pl
+++ b/src/bin/pg_verifybackup/t/003_corruption.pl
@@ -246,7 +246,7 @@ sub mutilate_extra_tablespace_file
sub mutilate_missing_file
{
my ($backup_path) = @_;
- my $pathname = "$backup_path/pg_xact/0000";
+ my $pathname = "$backup_path/pg_xact/000000000000000";
unlink($pathname) || die "$pathname: $!";
return;
}
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index e142800aab2..ecf2ca79692 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -131,13 +131,6 @@ typedef struct SlruCtlData
/* Number of banks in this SLRU. */
uint16 nbanks;
- /*
- * If true, use long segment file names. Otherwise, use short file names.
- *
- * For details about the file name format, see SlruFileName().
- */
- bool long_segment_names;
-
/*
* Which sync handler function to use when handing sync requests over to
* the checkpointer. SYNC_HANDLER_NONE to disable fsync (eg pg_notify).
@@ -184,8 +177,7 @@ extern Size SimpleLruShmemSize(int nslots, int nlsns);
extern int SimpleLruAutotuneBuffers(int divisor, int max);
extern void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id,
- int bank_tranche_id, SyncRequestHandler sync_handler,
- bool long_segment_names);
+ int bank_tranche_id, SyncRequestHandler sync_handler);
extern int SimpleLruZeroPage(SlruCtl ctl, int64 pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int64 pageno, bool write_ok,
TransactionId xid);
diff --git a/src/test/modules/test_slru/test_slru.c b/src/test/modules/test_slru/test_slru.c
index 3ea5ceb8552..cbd5173015a 100644
--- a/src/test/modules/test_slru/test_slru.c
+++ b/src/test/modules/test_slru/test_slru.c
@@ -213,11 +213,6 @@ test_slru_page_precedes_logically(int64 page1, int64 page2)
static void
test_slru_shmem_startup(void)
{
- /*
- * Short segments names are well tested elsewhere so in this test we are
- * focusing on long names.
- */
- const bool long_segment_names = true;
const char slru_dir_name[] = "pg_test_slru";
int test_tranche_id;
int test_buffer_tranche_id;
@@ -241,8 +236,7 @@ test_slru_shmem_startup(void)
TestSlruCtl->PagePrecedes = test_slru_page_precedes_logically;
SimpleLruInit(TestSlruCtl, "TestSLRU",
NUM_TEST_BUFFERS, 0, slru_dir_name,
- test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE,
- long_segment_names);
+ test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE);
}
void
--
2.48.1
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2025-03-28 20:27 Rustam ALLAKOV <[email protected]>
parent: Aleksander Alekseev <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Rustam ALLAKOV @ 2025-03-28 20:27 UTC (permalink / raw)
To: [email protected]; +Cc: Aleksander Alekseev <[email protected]>
The following review has been posted through the commitfest application:
make installcheck-world: tested, passed
Implements feature: tested, passed
Spec compliant: tested, passed
Documentation: tested, passed
Hi Aleksander,
I have reviewed your patch. It looks good to me.
Kindest regards.
Rustam Allakov
The new status of this patch is: Ready for Committer
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2025-04-03 14:25 Aleksander Alekseev <[email protected]>
parent: Rustam ALLAKOV <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Aleksander Alekseev @ 2025-04-03 14:25 UTC (permalink / raw)
To: [email protected]; +Cc: Rustam ALLAKOV <[email protected]>; Michael Paquier <[email protected]>
Hi Rustam,
> Hi Aleksander,
> I have reviewed your patch. It looks good to me.
>
> Kindest regards.
> Rustam Allakov
>
> The new status of this patch is: Ready for Committer
Thanks for testing!
Here is the rebased patch.
--
Best regards,
Aleksander Alekseev
Attachments:
[application/octet-stream] v5-0001-Always-use-long-SLRU-segment-file-names.patch (14.9K, 2-v5-0001-Always-use-long-SLRU-segment-file-names.patch)
download | inline diff:
From b0b98310672de9181e7006fd28a6ed2e12e11851 Mon Sep 17 00:00:00 2001
From: Aleksander Alekseev <[email protected]>
Date: Wed, 11 Sep 2024 13:17:33 +0300
Subject: [PATCH v5] Always use long SLRU segment file names
PG17 introduced long SLRU segment file names (commit 4ed8f0913bfd). We used
short or long file names depending on SlruCtl->long_segment_names. This commit
refactors SLRU to always use long file names in order to simplify the code.
Aleksander Alekseev, reviewed by Michael Paquier, Rustam Allakov
Discussion: https://postgr.es/m/CAJ7c6TOy7fUW9MuNeOWor3cSFnQg9tgz=mjXHDb94GORtM_Eyg@mail.gmail.com
(!!!) bump catversion and change the corresponding TODO FIXME line in pg_upgrade.h
---
src/backend/access/transam/clog.c | 2 +-
src/backend/access/transam/commit_ts.c | 3 +-
src/backend/access/transam/multixact.c | 6 +-
src/backend/access/transam/slru.c | 71 ++++----------------
src/backend/access/transam/subtrans.c | 2 +-
src/backend/commands/async.c | 2 +-
src/backend/storage/lmgr/predicate.c | 2 +-
src/bin/pg_upgrade/pg_upgrade.c | 74 +++++++++++++++++++++
src/bin/pg_upgrade/pg_upgrade.h | 6 ++
src/bin/pg_verifybackup/t/003_corruption.pl | 2 +-
src/include/access/slru.h | 10 +--
src/test/modules/test_slru/test_slru.c | 8 +--
12 files changed, 103 insertions(+), 85 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 48f10bec91e..f130403ac4b 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -810,7 +810,7 @@ CLOGShmemInit(void)
XactCtl->PagePrecedes = CLOGPagePrecedes;
SimpleLruInit(XactCtl, "transaction", CLOGShmemBuffers(), CLOG_LSNS_PER_PAGE,
"pg_xact", LWTRANCHE_XACT_BUFFER,
- LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG, false);
+ LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG);
SlruPagePrecedesUnitTests(XactCtl, CLOG_XACTS_PER_PAGE);
}
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 113fae1437a..59535526823 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -556,8 +556,7 @@ CommitTsShmemInit(void)
SimpleLruInit(CommitTsCtl, "commit_timestamp", CommitTsShmemBuffers(), 0,
"pg_commit_ts", LWTRANCHE_COMMITTS_BUFFER,
LWTRANCHE_COMMITTS_SLRU,
- SYNC_HANDLER_COMMIT_TS,
- false);
+ SYNC_HANDLER_COMMIT_TS);
SlruPagePrecedesUnitTests(CommitTsCtl, COMMIT_TS_XACTS_PER_PAGE);
commitTsShared = ShmemInitStruct("CommitTs shared",
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 9d25a7df0d3..8d8f7d28a06 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1974,15 +1974,13 @@ MultiXactShmemInit(void)
"multixact_offset", multixact_offset_buffers, 0,
"pg_multixact/offsets", LWTRANCHE_MULTIXACTOFFSET_BUFFER,
LWTRANCHE_MULTIXACTOFFSET_SLRU,
- SYNC_HANDLER_MULTIXACT_OFFSET,
- false);
+ SYNC_HANDLER_MULTIXACT_OFFSET);
SlruPagePrecedesUnitTests(MultiXactOffsetCtl, MULTIXACT_OFFSETS_PER_PAGE);
SimpleLruInit(MultiXactMemberCtl,
"multixact_member", multixact_member_buffers, 0,
"pg_multixact/members", LWTRANCHE_MULTIXACTMEMBER_BUFFER,
LWTRANCHE_MULTIXACTMEMBER_SLRU,
- SYNC_HANDLER_MULTIXACT_MEMBER,
- false);
+ SYNC_HANDLER_MULTIXACT_MEMBER);
/* doesn't call SimpleLruTruncate() or meet criteria for unit tests */
/* Initialize our shared state struct */
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index fe56286d9a9..752aa71fa87 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -77,41 +77,21 @@
*
* "path" should point to a buffer at least MAXPGPATH characters long.
*
- * If ctl->long_segment_names is true, segno can be in the range [0, 2^60-1].
- * The resulting file name is made of 15 characters, e.g. dir/123456789ABCDEF.
- *
- * If ctl->long_segment_names is false, segno can be in the range [0, 2^24-1].
- * The resulting file name is made of 4 to 6 characters, as of:
- *
- * dir/1234 for [0, 2^16-1]
- * dir/12345 for [2^16, 2^20-1]
- * dir/123456 for [2^20, 2^24-1]
+ * segno can be in the range [0, 2^60-1]. The resulting file name is made
+ * of 15 characters, e.g. dir/123456789ABCDEF.
*/
static inline int
SlruFileName(SlruCtl ctl, char *path, int64 segno)
{
- if (ctl->long_segment_names)
- {
- /*
- * We could use 16 characters here but the disadvantage would be that
- * the SLRU segments will be hard to distinguish from WAL segments.
- *
- * For this reason we use 15 characters. It is enough but also means
- * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
- }
- else
- {
- /*
- * Despite the fact that %04X format string is used up to 24 bit
- * integers are allowed. See SlruCorrectSegmentFilenameLength()
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir,
- (unsigned int) segno);
- }
+ /*
+ * We could use 16 characters here but the disadvantage would be that
+ * the SLRU segments will be hard to distinguish from WAL segments.
+ *
+ * For this reason we use 15 characters. It is enough but also means
+ * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
+ */
+ Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
+ return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
}
/*
@@ -250,7 +230,7 @@ SimpleLruAutotuneBuffers(int divisor, int max)
void
SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id, int bank_tranche_id,
- SyncRequestHandler sync_handler, bool long_segment_names)
+ SyncRequestHandler sync_handler)
{
SlruShared shared;
bool found;
@@ -341,7 +321,6 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
*/
ctl->shared = shared;
ctl->sync_handler = sync_handler;
- ctl->long_segment_names = long_segment_names;
ctl->nbanks = nbanks;
strlcpy(ctl->Dir, subdir, sizeof(ctl->Dir));
}
@@ -1747,30 +1726,6 @@ SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage, void *data)
return false; /* keep going */
}
-/*
- * An internal function used by SlruScanDirectory().
- *
- * Returns true if a file with a name of a given length may be a correct
- * SLRU segment.
- */
-static inline bool
-SlruCorrectSegmentFilenameLength(SlruCtl ctl, size_t len)
-{
- if (ctl->long_segment_names)
- return (len == 15); /* see SlruFileName() */
- else
-
- /*
- * Commit 638cf09e76d allowed 5-character lengths. Later commit
- * 73c986adde5 allowed 6-character length.
- *
- * Note: There is an ongoing plan to migrate all SLRUs to 64-bit page
- * numbers, and the corresponding 15-character file names, which may
- * eventually deprecate the support for 4, 5, and 6-character names.
- */
- return (len == 4 || len == 5 || len == 6);
-}
-
/*
* Scan the SimpleLru directory and apply a callback to each file found in it.
*
@@ -1802,7 +1757,7 @@ SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data)
len = strlen(clde->d_name);
- if (SlruCorrectSegmentFilenameLength(ctl, len) &&
+ if ((len == 15) &&
strspn(clde->d_name, "0123456789ABCDEF") == len)
{
segno = strtoi64(clde->d_name, NULL, 16);
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index 15153618fad..58a5ef657ea 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -243,7 +243,7 @@ SUBTRANSShmemInit(void)
SubTransCtl->PagePrecedes = SubTransPagePrecedes;
SimpleLruInit(SubTransCtl, "subtransaction", SUBTRANSShmemBuffers(), 0,
"pg_subtrans", LWTRANCHE_SUBTRANS_BUFFER,
- LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE, false);
+ LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE);
SlruPagePrecedesUnitTests(SubTransCtl, SUBTRANS_XACTS_PER_PAGE);
}
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 4bd37d5beb5..373b0357fad 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -537,7 +537,7 @@ AsyncShmemInit(void)
NotifyCtl->PagePrecedes = asyncQueuePagePrecedes;
SimpleLruInit(NotifyCtl, "notify", notify_buffers, 0,
"pg_notify", LWTRANCHE_NOTIFY_BUFFER, LWTRANCHE_NOTIFY_SLRU,
- SYNC_HANDLER_NONE, true);
+ SYNC_HANDLER_NONE);
if (!found)
{
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index d82114ffca1..b029b12601e 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -814,7 +814,7 @@ SerialInit(void)
SimpleLruInit(SerialSlruCtl, "serializable",
serializable_buffers, 0, "pg_serial",
LWTRANCHE_SERIAL_BUFFER, LWTRANCHE_SERIAL_SLRU,
- SYNC_HANDLER_NONE, false);
+ SYNC_HANDLER_NONE);
#ifdef USE_ASSERT_CHECKING
SerialPagePrecedesLogicallyUnitTests();
#endif
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index 9295e46aed3..df0bb7df1aa 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -38,6 +38,7 @@
#include "postgres_fe.h"
+#include <dirent.h>
#include <time.h>
#include "catalog/pg_class_d.h"
@@ -60,6 +61,8 @@ static void prepare_new_cluster(void);
static void prepare_new_globals(void);
static void create_new_objects(void);
static void copy_xact_xlog_xid(void);
+static void check_slru_segment_filenames(void);
+static void rename_slru_segments(const char *dirname);
static void set_frozenxids(bool minmxid_only);
static void make_outputdirs(char *pgdata);
static void setup(char *argv0);
@@ -156,6 +159,7 @@ main(int argc, char **argv)
copy_xact_xlog_xid();
set_new_cluster_char_signedness();
+ check_slru_segment_filenames();
/* New now using xids of the old system */
@@ -843,6 +847,76 @@ copy_xact_xlog_xid(void)
check_ok();
}
+static void
+rename_slru_segments(const char* dirname)
+{
+ DIR *dir;
+ struct dirent *de;
+ int len;
+ int64 segno;
+ char dir_path[MAXPGPATH];
+ char old_path[MAXPGPATH];
+ char new_path[MAXPGPATH];
+
+ prep_status("Renaming SLRU segments in %s", dirname);
+ snprintf(dir_path, sizeof(dir_path), "%s/%s", new_cluster.pgdata, dirname);
+
+ dir = opendir(dir_path);
+ if (dir == NULL)
+ pg_fatal("could not open directory \"%s\": %m", dir_path);
+
+ while (errno = 0, (de = readdir(dir)) != NULL)
+ {
+ /*
+ * ignore '.', '..' and everything else that doesn't look
+ * like an SLRU segment with a short file name
+ */
+
+ len = strlen(de->d_name);
+ if(len != 4 && len != 5 && len != 6)
+ continue;
+
+ if(strspn(de->d_name, "0123456789ABCDEF") != len)
+ continue;
+
+ segno = strtoi64(de->d_name, NULL, 16);
+ snprintf(new_path, MAXPGPATH, "%s/%015llX", dir_path,
+ (long long) segno);
+ snprintf(old_path, MAXPGPATH, "%s/%s", dir_path, de->d_name);
+
+ if (pg_mv_file(old_path, new_path) != 0)
+ pg_fatal("could not rename file \"%s\" to \"%s\": %m",
+ old_path, new_path);
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %m", dir_path);
+
+ if (closedir(dir))
+ pg_fatal("could not close directory \"%s\": %m", dir_path);
+
+ check_ok();
+}
+
+static void
+check_slru_segment_filenames(void)
+{
+ int i;
+ static const char* dirs[] = {
+ "pg_xact",
+ "pg_commit_ts",
+ "pg_multixact/offsets",
+ "pg_multixact/members",
+ "pg_subtrans",
+ "pg_serial",
+ };
+
+ if(old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
+ return;
+
+ for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); i++)
+ rename_slru_segments(dirs[i]);
+}
/*
* set_frozenxids()
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 69c965bb7d0..32c6ac49138 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -131,6 +131,12 @@ extern char *output_files[];
*/
#define DEFAULT_CHAR_SIGNEDNESS_CAT_VER 202502212
+/*
+ * change of SLRU segment filenames length in 18.0
+ * TODO FIXME CHANGE TO THE ACTUAL VALUE BEFORE COMMITTING
+ */
+#define SLRU_SEG_FILENAMES_CHANGE_CAT_VER 202412201
+
/*
* Each relation is represented by a relinfo structure.
*/
diff --git a/src/bin/pg_verifybackup/t/003_corruption.pl b/src/bin/pg_verifybackup/t/003_corruption.pl
index 84f23b8bc3d..df215378e74 100644
--- a/src/bin/pg_verifybackup/t/003_corruption.pl
+++ b/src/bin/pg_verifybackup/t/003_corruption.pl
@@ -246,7 +246,7 @@ sub mutilate_extra_tablespace_file
sub mutilate_missing_file
{
my ($backup_path) = @_;
- my $pathname = "$backup_path/pg_xact/0000";
+ my $pathname = "$backup_path/pg_xact/000000000000000";
unlink($pathname) || die "$pathname: $!";
return;
}
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index e142800aab2..ecf2ca79692 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -131,13 +131,6 @@ typedef struct SlruCtlData
/* Number of banks in this SLRU. */
uint16 nbanks;
- /*
- * If true, use long segment file names. Otherwise, use short file names.
- *
- * For details about the file name format, see SlruFileName().
- */
- bool long_segment_names;
-
/*
* Which sync handler function to use when handing sync requests over to
* the checkpointer. SYNC_HANDLER_NONE to disable fsync (eg pg_notify).
@@ -184,8 +177,7 @@ extern Size SimpleLruShmemSize(int nslots, int nlsns);
extern int SimpleLruAutotuneBuffers(int divisor, int max);
extern void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id,
- int bank_tranche_id, SyncRequestHandler sync_handler,
- bool long_segment_names);
+ int bank_tranche_id, SyncRequestHandler sync_handler);
extern int SimpleLruZeroPage(SlruCtl ctl, int64 pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int64 pageno, bool write_ok,
TransactionId xid);
diff --git a/src/test/modules/test_slru/test_slru.c b/src/test/modules/test_slru/test_slru.c
index 2e4492900af..171076d9209 100644
--- a/src/test/modules/test_slru/test_slru.c
+++ b/src/test/modules/test_slru/test_slru.c
@@ -213,11 +213,6 @@ test_slru_page_precedes_logically(int64 page1, int64 page2)
static void
test_slru_shmem_startup(void)
{
- /*
- * Short segments names are well tested elsewhere so in this test we are
- * focusing on long names.
- */
- const bool long_segment_names = true;
const char slru_dir_name[] = "pg_test_slru";
int test_tranche_id;
int test_buffer_tranche_id;
@@ -241,8 +236,7 @@ test_slru_shmem_startup(void)
TestSlruCtl->PagePrecedes = test_slru_page_precedes_logically;
SimpleLruInit(TestSlruCtl, "TestSLRU",
NUM_TEST_BUFFERS, 0, slru_dir_name,
- test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE,
- long_segment_names);
+ test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE);
}
void
--
2.49.0
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2025-08-13 11:54 Aleksander Alekseev <[email protected]>
parent: Aleksander Alekseev <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Aleksander Alekseev @ 2025-08-13 11:54 UTC (permalink / raw)
To: [email protected]; +Cc: Rustam ALLAKOV <[email protected]>; Michael Paquier <[email protected]>
Hi,
> > The new status of this patch is: Ready for Committer
>
> Thanks for testing!
>
> Here is the rebased patch.
Rebased.
Attachments:
[text/x-patch] v6-0001-Always-use-long-SLRU-segment-file-names.patch (15.0K, 2-v6-0001-Always-use-long-SLRU-segment-file-names.patch)
download | inline diff:
From 4d83acd61eee36784840e2d1228d0c854807bac0 Mon Sep 17 00:00:00 2001
From: Aleksander Alekseev <[email protected]>
Date: Wed, 11 Sep 2024 13:17:33 +0300
Subject: [PATCH v6] Always use long SLRU segment file names
PG17 introduced long SLRU segment file names (commit 4ed8f0913bfd). We used
short or long file names depending on SlruCtl->long_segment_names. This commit
refactors SLRU to always use long file names in order to simplify the code.
Aleksander Alekseev, reviewed by Michael Paquier, Rustam Allakov
Discussion: https://postgr.es/m/CAJ7c6TOy7fUW9MuNeOWor3cSFnQg9tgz=mjXHDb94GORtM_Eyg@mail.gmail.com
(!!!) bump catversion and change the corresponding TODO FIXME line in pg_upgrade.h
---
src/backend/access/transam/clog.c | 2 +-
src/backend/access/transam/commit_ts.c | 3 +-
src/backend/access/transam/multixact.c | 6 +-
src/backend/access/transam/slru.c | 71 ++++----------------
src/backend/access/transam/subtrans.c | 2 +-
src/backend/commands/async.c | 2 +-
src/backend/storage/lmgr/predicate.c | 2 +-
src/bin/pg_upgrade/pg_upgrade.c | 74 +++++++++++++++++++++
src/bin/pg_upgrade/pg_upgrade.h | 6 ++
src/bin/pg_verifybackup/t/003_corruption.pl | 2 +-
src/include/access/slru.h | 10 +--
src/test/modules/test_slru/test_slru.c | 8 +--
12 files changed, 103 insertions(+), 85 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index e80fbe109cf..b6603cacf82 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -808,7 +808,7 @@ CLOGShmemInit(void)
XactCtl->PagePrecedes = CLOGPagePrecedes;
SimpleLruInit(XactCtl, "transaction", CLOGShmemBuffers(), CLOG_LSNS_PER_PAGE,
"pg_xact", LWTRANCHE_XACT_BUFFER,
- LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG, false);
+ LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG);
SlruPagePrecedesUnitTests(XactCtl, CLOG_XACTS_PER_PAGE);
}
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 370b38e048b..7798f217e75 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -554,8 +554,7 @@ CommitTsShmemInit(void)
SimpleLruInit(CommitTsCtl, "commit_timestamp", CommitTsShmemBuffers(), 0,
"pg_commit_ts", LWTRANCHE_COMMITTS_BUFFER,
LWTRANCHE_COMMITTS_SLRU,
- SYNC_HANDLER_COMMIT_TS,
- false);
+ SYNC_HANDLER_COMMIT_TS);
SlruPagePrecedesUnitTests(CommitTsCtl, COMMIT_TS_XACTS_PER_PAGE);
commitTsShared = ShmemInitStruct("CommitTs shared",
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 3cb09c3d598..d1c04948290 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1971,15 +1971,13 @@ MultiXactShmemInit(void)
"multixact_offset", multixact_offset_buffers, 0,
"pg_multixact/offsets", LWTRANCHE_MULTIXACTOFFSET_BUFFER,
LWTRANCHE_MULTIXACTOFFSET_SLRU,
- SYNC_HANDLER_MULTIXACT_OFFSET,
- false);
+ SYNC_HANDLER_MULTIXACT_OFFSET);
SlruPagePrecedesUnitTests(MultiXactOffsetCtl, MULTIXACT_OFFSETS_PER_PAGE);
SimpleLruInit(MultiXactMemberCtl,
"multixact_member", multixact_member_buffers, 0,
"pg_multixact/members", LWTRANCHE_MULTIXACTMEMBER_BUFFER,
LWTRANCHE_MULTIXACTMEMBER_SLRU,
- SYNC_HANDLER_MULTIXACT_MEMBER,
- false);
+ SYNC_HANDLER_MULTIXACT_MEMBER);
/* doesn't call SimpleLruTruncate() or meet criteria for unit tests */
/* Initialize our shared state struct */
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 10ec259f382..3006def1f83 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -77,41 +77,21 @@
*
* "path" should point to a buffer at least MAXPGPATH characters long.
*
- * If ctl->long_segment_names is true, segno can be in the range [0, 2^60-1].
- * The resulting file name is made of 15 characters, e.g. dir/123456789ABCDEF.
- *
- * If ctl->long_segment_names is false, segno can be in the range [0, 2^24-1].
- * The resulting file name is made of 4 to 6 characters, as of:
- *
- * dir/1234 for [0, 2^16-1]
- * dir/12345 for [2^16, 2^20-1]
- * dir/123456 for [2^20, 2^24-1]
+ * segno can be in the range [0, 2^60-1]. The resulting file name is made
+ * of 15 characters, e.g. dir/123456789ABCDEF.
*/
static inline int
SlruFileName(SlruCtl ctl, char *path, int64 segno)
{
- if (ctl->long_segment_names)
- {
- /*
- * We could use 16 characters here but the disadvantage would be that
- * the SLRU segments will be hard to distinguish from WAL segments.
- *
- * For this reason we use 15 characters. It is enough but also means
- * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
- }
- else
- {
- /*
- * Despite the fact that %04X format string is used up to 24 bit
- * integers are allowed. See SlruCorrectSegmentFilenameLength()
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir,
- (unsigned int) segno);
- }
+ /*
+ * We could use 16 characters here but the disadvantage would be that
+ * the SLRU segments will be hard to distinguish from WAL segments.
+ *
+ * For this reason we use 15 characters. It is enough but also means
+ * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
+ */
+ Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
+ return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
}
/*
@@ -250,7 +230,7 @@ SimpleLruAutotuneBuffers(int divisor, int max)
void
SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id, int bank_tranche_id,
- SyncRequestHandler sync_handler, bool long_segment_names)
+ SyncRequestHandler sync_handler)
{
SlruShared shared;
bool found;
@@ -341,7 +321,6 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
*/
ctl->shared = shared;
ctl->sync_handler = sync_handler;
- ctl->long_segment_names = long_segment_names;
ctl->nbanks = nbanks;
strlcpy(ctl->Dir, subdir, sizeof(ctl->Dir));
}
@@ -1772,30 +1751,6 @@ SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage, void *data)
return false; /* keep going */
}
-/*
- * An internal function used by SlruScanDirectory().
- *
- * Returns true if a file with a name of a given length may be a correct
- * SLRU segment.
- */
-static inline bool
-SlruCorrectSegmentFilenameLength(SlruCtl ctl, size_t len)
-{
- if (ctl->long_segment_names)
- return (len == 15); /* see SlruFileName() */
- else
-
- /*
- * Commit 638cf09e76d allowed 5-character lengths. Later commit
- * 73c986adde5 allowed 6-character length.
- *
- * Note: There is an ongoing plan to migrate all SLRUs to 64-bit page
- * numbers, and the corresponding 15-character file names, which may
- * eventually deprecate the support for 4, 5, and 6-character names.
- */
- return (len == 4 || len == 5 || len == 6);
-}
-
/*
* Scan the SimpleLru directory and apply a callback to each file found in it.
*
@@ -1827,7 +1782,7 @@ SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data)
len = strlen(clde->d_name);
- if (SlruCorrectSegmentFilenameLength(ctl, len) &&
+ if ((len == 15) &&
strspn(clde->d_name, "0123456789ABCDEF") == len)
{
segno = strtoi64(clde->d_name, NULL, 16);
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index 09aace9e09f..517089f0666 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -242,7 +242,7 @@ SUBTRANSShmemInit(void)
SubTransCtl->PagePrecedes = SubTransPagePrecedes;
SimpleLruInit(SubTransCtl, "subtransaction", SUBTRANSShmemBuffers(), 0,
"pg_subtrans", LWTRANCHE_SUBTRANS_BUFFER,
- LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE, false);
+ LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE);
SlruPagePrecedesUnitTests(SubTransCtl, SUBTRANS_XACTS_PER_PAGE);
}
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 4bd37d5beb5..373b0357fad 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -537,7 +537,7 @@ AsyncShmemInit(void)
NotifyCtl->PagePrecedes = asyncQueuePagePrecedes;
SimpleLruInit(NotifyCtl, "notify", notify_buffers, 0,
"pg_notify", LWTRANCHE_NOTIFY_BUFFER, LWTRANCHE_NOTIFY_SLRU,
- SYNC_HANDLER_NONE, true);
+ SYNC_HANDLER_NONE);
if (!found)
{
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index c07fb588355..d6117eb72f6 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -814,7 +814,7 @@ SerialInit(void)
SimpleLruInit(SerialSlruCtl, "serializable",
serializable_buffers, 0, "pg_serial",
LWTRANCHE_SERIAL_BUFFER, LWTRANCHE_SERIAL_SLRU,
- SYNC_HANDLER_NONE, false);
+ SYNC_HANDLER_NONE);
#ifdef USE_ASSERT_CHECKING
SerialPagePrecedesLogicallyUnitTests();
#endif
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index d5cd5bf0b3a..52f6a1cdfec 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -41,6 +41,7 @@
#include "postgres_fe.h"
+#include <dirent.h>
#include <time.h>
#include "catalog/pg_class_d.h"
@@ -63,6 +64,8 @@ static void prepare_new_cluster(void);
static void prepare_new_globals(void);
static void create_new_objects(void);
static void copy_xact_xlog_xid(void);
+static void check_slru_segment_filenames(void);
+static void rename_slru_segments(const char *dirname);
static void set_frozenxids(bool minmxid_only);
static void make_outputdirs(char *pgdata);
static void setup(char *argv0);
@@ -161,6 +164,7 @@ main(int argc, char **argv)
copy_xact_xlog_xid();
set_new_cluster_char_signedness();
+ check_slru_segment_filenames();
/* New now using xids of the old system */
@@ -872,6 +876,76 @@ copy_xact_xlog_xid(void)
check_ok();
}
+static void
+rename_slru_segments(const char* dirname)
+{
+ DIR *dir;
+ struct dirent *de;
+ int len;
+ int64 segno;
+ char dir_path[MAXPGPATH];
+ char old_path[MAXPGPATH];
+ char new_path[MAXPGPATH];
+
+ prep_status("Renaming SLRU segments in %s", dirname);
+ snprintf(dir_path, sizeof(dir_path), "%s/%s", new_cluster.pgdata, dirname);
+
+ dir = opendir(dir_path);
+ if (dir == NULL)
+ pg_fatal("could not open directory \"%s\": %m", dir_path);
+
+ while (errno = 0, (de = readdir(dir)) != NULL)
+ {
+ /*
+ * ignore '.', '..' and everything else that doesn't look
+ * like an SLRU segment with a short file name
+ */
+
+ len = strlen(de->d_name);
+ if(len != 4 && len != 5 && len != 6)
+ continue;
+
+ if(strspn(de->d_name, "0123456789ABCDEF") != len)
+ continue;
+
+ segno = strtoi64(de->d_name, NULL, 16);
+ snprintf(new_path, MAXPGPATH, "%s/%015llX", dir_path,
+ (long long) segno);
+ snprintf(old_path, MAXPGPATH, "%s/%s", dir_path, de->d_name);
+
+ if (pg_mv_file(old_path, new_path) != 0)
+ pg_fatal("could not rename file \"%s\" to \"%s\": %m",
+ old_path, new_path);
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %m", dir_path);
+
+ if (closedir(dir))
+ pg_fatal("could not close directory \"%s\": %m", dir_path);
+
+ check_ok();
+}
+
+static void
+check_slru_segment_filenames(void)
+{
+ int i;
+ static const char* dirs[] = {
+ "pg_xact",
+ "pg_commit_ts",
+ "pg_multixact/offsets",
+ "pg_multixact/members",
+ "pg_subtrans",
+ "pg_serial",
+ };
+
+ if(old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
+ return;
+
+ for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); i++)
+ rename_slru_segments(dirs[i]);
+}
/*
* set_frozenxids()
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 0ef47be0dc1..73d102529c3 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -131,6 +131,12 @@ extern char *output_files[];
*/
#define DEFAULT_CHAR_SIGNEDNESS_CAT_VER 202502212
+/*
+ * change of SLRU segment filenames length in 18.0
+ * TODO FIXME CHANGE TO THE ACTUAL VALUE BEFORE COMMITTING
+ */
+#define SLRU_SEG_FILENAMES_CHANGE_CAT_VER 202412201
+
/*
* Each relation is represented by a relinfo structure.
*/
diff --git a/src/bin/pg_verifybackup/t/003_corruption.pl b/src/bin/pg_verifybackup/t/003_corruption.pl
index 1dd60f709cf..deb8c11ca9e 100644
--- a/src/bin/pg_verifybackup/t/003_corruption.pl
+++ b/src/bin/pg_verifybackup/t/003_corruption.pl
@@ -246,7 +246,7 @@ sub mutilate_extra_tablespace_file
sub mutilate_missing_file
{
my ($backup_path) = @_;
- my $pathname = "$backup_path/pg_xact/0000";
+ my $pathname = "$backup_path/pg_xact/000000000000000";
unlink($pathname) || die "$pathname: $!";
return;
}
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index 20dbd1e0070..186d9cb1a10 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -131,13 +131,6 @@ typedef struct SlruCtlData
/* Number of banks in this SLRU. */
uint16 nbanks;
- /*
- * If true, use long segment file names. Otherwise, use short file names.
- *
- * For details about the file name format, see SlruFileName().
- */
- bool long_segment_names;
-
/*
* Which sync handler function to use when handing sync requests over to
* the checkpointer. SYNC_HANDLER_NONE to disable fsync (eg pg_notify).
@@ -184,8 +177,7 @@ extern Size SimpleLruShmemSize(int nslots, int nlsns);
extern int SimpleLruAutotuneBuffers(int divisor, int max);
extern void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id,
- int bank_tranche_id, SyncRequestHandler sync_handler,
- bool long_segment_names);
+ int bank_tranche_id, SyncRequestHandler sync_handler);
extern int SimpleLruZeroPage(SlruCtl ctl, int64 pageno);
extern void SimpleLruZeroAndWritePage(SlruCtl ctl, int64 pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int64 pageno, bool write_ok,
diff --git a/src/test/modules/test_slru/test_slru.c b/src/test/modules/test_slru/test_slru.c
index 32750930e43..483c06edfc7 100644
--- a/src/test/modules/test_slru/test_slru.c
+++ b/src/test/modules/test_slru/test_slru.c
@@ -213,11 +213,6 @@ test_slru_page_precedes_logically(int64 page1, int64 page2)
static void
test_slru_shmem_startup(void)
{
- /*
- * Short segments names are well tested elsewhere so in this test we are
- * focusing on long names.
- */
- const bool long_segment_names = true;
const char slru_dir_name[] = "pg_test_slru";
int test_tranche_id;
int test_buffer_tranche_id;
@@ -241,8 +236,7 @@ test_slru_shmem_startup(void)
TestSlruCtl->PagePrecedes = test_slru_page_precedes_logically;
SimpleLruInit(TestSlruCtl, "TestSLRU",
NUM_TEST_BUFFERS, 0, slru_dir_name,
- test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE,
- long_segment_names);
+ test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE);
}
void
--
2.43.0
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2026-01-06 15:18 Aleksander Alekseev <[email protected]>
parent: Aleksander Alekseev <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Aleksander Alekseev @ 2026-01-06 15:18 UTC (permalink / raw)
To: [email protected]; +Cc: Rustam ALLAKOV <[email protected]>; Michael Paquier <[email protected]>
Hi,
> > > The new status of this patch is: Ready for Committer
> >
> > Thanks for testing!
> >
> > Here is the rebased patch.
>
> Rebased.
Rebased.
--
Best regards,
Aleksander Alekseev
Attachments:
[text/x-patch] v7-0001-Always-use-long-SLRU-segment-file-names.patch (16.3K, 2-v7-0001-Always-use-long-SLRU-segment-file-names.patch)
download | inline diff:
From 89ee21b95411af09aa5ec546cb6a59369653ff6d Mon Sep 17 00:00:00 2001
From: Aleksander Alekseev <[email protected]>
Date: Wed, 11 Sep 2024 13:17:33 +0300
Subject: [PATCH v7] Always use long SLRU segment file names
PG17 introduced long SLRU segment file names (commit 4ed8f0913bfd). We used
short or long file names depending on SlruCtl->long_segment_names. This commit
refactors SLRU to always use long file names in order to simplify the code.
Aleksander Alekseev, reviewed by Michael Paquier, Rustam Allakov
Discussion: https://postgr.es/m/CAJ7c6TOy7fUW9MuNeOWor3cSFnQg9tgz=mjXHDb94GORtM_Eyg@mail.gmail.com
(!!!) bump catversion and change the corresponding TODO FIXME line in pg_upgrade.h
---
src/backend/access/transam/clog.c | 2 +-
src/backend/access/transam/commit_ts.c | 3 +-
src/backend/access/transam/multixact.c | 6 +-
src/backend/access/transam/slru.c | 71 ++++--------------
src/backend/access/transam/subtrans.c | 2 +-
src/backend/commands/async.c | 2 +-
src/backend/storage/lmgr/predicate.c | 2 +-
src/bin/pg_upgrade/pg_upgrade.c | 74 +++++++++++++++++++
src/bin/pg_upgrade/pg_upgrade.h | 6 ++
src/bin/pg_verifybackup/t/003_corruption.pl | 2 +-
src/include/access/slru.h | 10 +--
.../test_slru/t/002_multixact_wraparound.pl | 6 +-
src/test/modules/test_slru/test_slru.c | 8 +-
13 files changed, 106 insertions(+), 88 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index b5c38bbb162..e46dc13fb5a 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -809,7 +809,7 @@ CLOGShmemInit(void)
XactCtl->PagePrecedes = CLOGPagePrecedes;
SimpleLruInit(XactCtl, "transaction", CLOGShmemBuffers(), CLOG_LSNS_PER_PAGE,
"pg_xact", LWTRANCHE_XACT_BUFFER,
- LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG, false);
+ LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG);
SlruPagePrecedesUnitTests(XactCtl, CLOG_XACTS_PER_PAGE);
}
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 082b564da8f..25774fbc1b9 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -554,8 +554,7 @@ CommitTsShmemInit(void)
SimpleLruInit(CommitTsCtl, "commit_timestamp", CommitTsShmemBuffers(), 0,
"pg_commit_ts", LWTRANCHE_COMMITTS_BUFFER,
LWTRANCHE_COMMITTS_SLRU,
- SYNC_HANDLER_COMMIT_TS,
- false);
+ SYNC_HANDLER_COMMIT_TS);
SlruPagePrecedesUnitTests(CommitTsCtl, COMMIT_TS_XACTS_PER_PAGE);
commitTsShared = ShmemInitStruct("CommitTs shared",
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 3f423636b48..3482b1c16ad 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1736,15 +1736,13 @@ MultiXactShmemInit(void)
"multixact_offset", multixact_offset_buffers, 0,
"pg_multixact/offsets", LWTRANCHE_MULTIXACTOFFSET_BUFFER,
LWTRANCHE_MULTIXACTOFFSET_SLRU,
- SYNC_HANDLER_MULTIXACT_OFFSET,
- false);
+ SYNC_HANDLER_MULTIXACT_OFFSET);
SlruPagePrecedesUnitTests(MultiXactOffsetCtl, MULTIXACT_OFFSETS_PER_PAGE);
SimpleLruInit(MultiXactMemberCtl,
"multixact_member", multixact_member_buffers, 0,
"pg_multixact/members", LWTRANCHE_MULTIXACTMEMBER_BUFFER,
LWTRANCHE_MULTIXACTMEMBER_SLRU,
- SYNC_HANDLER_MULTIXACT_MEMBER,
- true);
+ SYNC_HANDLER_MULTIXACT_MEMBER);
/* doesn't call SimpleLruTruncate() or meet criteria for unit tests */
/* Initialize our shared state struct */
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 549c7e3e64b..18baedd6de6 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -77,41 +77,21 @@
*
* "path" should point to a buffer at least MAXPGPATH characters long.
*
- * If ctl->long_segment_names is true, segno can be in the range [0, 2^60-1].
- * The resulting file name is made of 15 characters, e.g. dir/123456789ABCDEF.
- *
- * If ctl->long_segment_names is false, segno can be in the range [0, 2^24-1].
- * The resulting file name is made of 4 to 6 characters, as of:
- *
- * dir/1234 for [0, 2^16-1]
- * dir/12345 for [2^16, 2^20-1]
- * dir/123456 for [2^20, 2^24-1]
+ * segno can be in the range [0, 2^60-1]. The resulting file name is made
+ * of 15 characters, e.g. dir/123456789ABCDEF.
*/
static inline int
SlruFileName(SlruCtl ctl, char *path, int64 segno)
{
- if (ctl->long_segment_names)
- {
- /*
- * We could use 16 characters here but the disadvantage would be that
- * the SLRU segments will be hard to distinguish from WAL segments.
- *
- * For this reason we use 15 characters. It is enough but also means
- * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
- }
- else
- {
- /*
- * Despite the fact that %04X format string is used up to 24 bit
- * integers are allowed. See SlruCorrectSegmentFilenameLength()
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir,
- (unsigned int) segno);
- }
+ /*
+ * We could use 16 characters here but the disadvantage would be that
+ * the SLRU segments will be hard to distinguish from WAL segments.
+ *
+ * For this reason we use 15 characters. It is enough but also means
+ * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
+ */
+ Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
+ return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
}
/*
@@ -251,7 +231,7 @@ SimpleLruAutotuneBuffers(int divisor, int max)
void
SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id, int bank_tranche_id,
- SyncRequestHandler sync_handler, bool long_segment_names)
+ SyncRequestHandler sync_handler)
{
SlruShared shared;
bool found;
@@ -342,7 +322,6 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
*/
ctl->shared = shared;
ctl->sync_handler = sync_handler;
- ctl->long_segment_names = long_segment_names;
ctl->nbanks = nbanks;
strlcpy(ctl->Dir, subdir, sizeof(ctl->Dir));
}
@@ -1773,30 +1752,6 @@ SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage, void *data)
return false; /* keep going */
}
-/*
- * An internal function used by SlruScanDirectory().
- *
- * Returns true if a file with a name of a given length may be a correct
- * SLRU segment.
- */
-static inline bool
-SlruCorrectSegmentFilenameLength(SlruCtl ctl, size_t len)
-{
- if (ctl->long_segment_names)
- return (len == 15); /* see SlruFileName() */
- else
-
- /*
- * Commit 638cf09e76d allowed 5-character lengths. Later commit
- * 73c986adde5 allowed 6-character length.
- *
- * Note: There is an ongoing plan to migrate all SLRUs to 64-bit page
- * numbers, and the corresponding 15-character file names, which may
- * eventually deprecate the support for 4, 5, and 6-character names.
- */
- return (len == 4 || len == 5 || len == 6);
-}
-
/*
* Scan the SimpleLru directory and apply a callback to each file found in it.
*
@@ -1828,7 +1783,7 @@ SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data)
len = strlen(clde->d_name);
- if (SlruCorrectSegmentFilenameLength(ctl, len) &&
+ if ((len == 15) &&
strspn(clde->d_name, "0123456789ABCDEF") == len)
{
segno = strtoi64(clde->d_name, NULL, 16);
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index c0987f43f11..3536971ca7d 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -242,7 +242,7 @@ SUBTRANSShmemInit(void)
SubTransCtl->PagePrecedes = SubTransPagePrecedes;
SimpleLruInit(SubTransCtl, "subtransaction", SUBTRANSShmemBuffers(), 0,
"pg_subtrans", LWTRANCHE_SUBTRANS_BUFFER,
- LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE, false);
+ LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE);
SlruPagePrecedesUnitTests(SubTransCtl, SUBTRANS_XACTS_PER_PAGE);
}
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 40c42f572ed..0dd1a923fc9 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -536,7 +536,7 @@ AsyncShmemInit(void)
NotifyCtl->PagePrecedes = asyncQueuePagePrecedes;
SimpleLruInit(NotifyCtl, "notify", notify_buffers, 0,
"pg_notify", LWTRANCHE_NOTIFY_BUFFER, LWTRANCHE_NOTIFY_SLRU,
- SYNC_HANDLER_NONE, true);
+ SYNC_HANDLER_NONE);
if (!found)
{
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index fe75ead3501..8e97bb35225 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -814,7 +814,7 @@ SerialInit(void)
SimpleLruInit(SerialSlruCtl, "serializable",
serializable_buffers, 0, "pg_serial",
LWTRANCHE_SERIAL_BUFFER, LWTRANCHE_SERIAL_SLRU,
- SYNC_HANDLER_NONE, false);
+ SYNC_HANDLER_NONE);
#ifdef USE_ASSERT_CHECKING
SerialPagePrecedesLogicallyUnitTests();
#endif
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index 2127d297bfe..434843e4afe 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -41,6 +41,7 @@
#include "postgres_fe.h"
+#include <dirent.h>
#include <time.h>
#include "access/multixact.h"
@@ -64,6 +65,8 @@ static void prepare_new_cluster(void);
static void prepare_new_globals(void);
static void create_new_objects(void);
static void copy_xact_xlog_xid(void);
+static void check_slru_segment_filenames(void);
+static void rename_slru_segments(const char *dirname);
static void set_frozenxids(bool minmxid_only);
static void make_outputdirs(char *pgdata);
static void setup(char *argv0);
@@ -162,6 +165,7 @@ main(int argc, char **argv)
copy_xact_xlog_xid();
set_new_cluster_char_signedness();
+ check_slru_segment_filenames();
/* New now using xids of the old system */
@@ -902,6 +906,76 @@ copy_xact_xlog_xid(void)
check_ok();
}
+static void
+rename_slru_segments(const char* dirname)
+{
+ DIR *dir;
+ struct dirent *de;
+ int len;
+ int64 segno;
+ char dir_path[MAXPGPATH];
+ char old_path[MAXPGPATH];
+ char new_path[MAXPGPATH];
+
+ prep_status("Renaming SLRU segments in %s", dirname);
+ snprintf(dir_path, sizeof(dir_path), "%s/%s", new_cluster.pgdata, dirname);
+
+ dir = opendir(dir_path);
+ if (dir == NULL)
+ pg_fatal("could not open directory \"%s\": %m", dir_path);
+
+ while (errno = 0, (de = readdir(dir)) != NULL)
+ {
+ /*
+ * ignore '.', '..' and everything else that doesn't look
+ * like an SLRU segment with a short file name
+ */
+
+ len = strlen(de->d_name);
+ if(len != 4 && len != 5 && len != 6)
+ continue;
+
+ if(strspn(de->d_name, "0123456789ABCDEF") != len)
+ continue;
+
+ segno = strtoi64(de->d_name, NULL, 16);
+ snprintf(new_path, MAXPGPATH, "%s/%015llX", dir_path,
+ (long long) segno);
+ snprintf(old_path, MAXPGPATH, "%s/%s", dir_path, de->d_name);
+
+ if (pg_mv_file(old_path, new_path) != 0)
+ pg_fatal("could not rename file \"%s\" to \"%s\": %m",
+ old_path, new_path);
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %m", dir_path);
+
+ if (closedir(dir))
+ pg_fatal("could not close directory \"%s\": %m", dir_path);
+
+ check_ok();
+}
+
+static void
+check_slru_segment_filenames(void)
+{
+ int i;
+ static const char* dirs[] = {
+ "pg_xact",
+ "pg_commit_ts",
+ "pg_multixact/offsets",
+ "pg_multixact/members",
+ "pg_subtrans",
+ "pg_serial",
+ };
+
+ if(old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
+ return;
+
+ for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); i++)
+ rename_slru_segments(dirs[i]);
+}
/*
* set_frozenxids()
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index ec018e4f292..58102e6a483 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -138,6 +138,12 @@ extern char *output_files[];
*/
#define DEFAULT_CHAR_SIGNEDNESS_CAT_VER 202502212
+/*
+ * change of SLRU segment filenames length in PG19
+ * TODO FIXME CHANGE TO THE ACTUAL VALUE BEFORE COMMITTING
+ */
+#define SLRU_SEG_FILENAMES_CHANGE_CAT_VER 202601061
+
/*
* Each relation is represented by a relinfo structure.
*/
diff --git a/src/bin/pg_verifybackup/t/003_corruption.pl b/src/bin/pg_verifybackup/t/003_corruption.pl
index b1d65b8aa0f..4677e9584ca 100644
--- a/src/bin/pg_verifybackup/t/003_corruption.pl
+++ b/src/bin/pg_verifybackup/t/003_corruption.pl
@@ -246,7 +246,7 @@ sub mutilate_extra_tablespace_file
sub mutilate_missing_file
{
my ($backup_path) = @_;
- my $pathname = "$backup_path/pg_xact/0000";
+ my $pathname = "$backup_path/pg_xact/000000000000000";
unlink($pathname) || die "$pathname: $!";
return;
}
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index 4cb8f478fce..541febf86bc 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -116,13 +116,6 @@ typedef struct SlruCtlData
/* Number of banks in this SLRU. */
uint16 nbanks;
- /*
- * If true, use long segment file names. Otherwise, use short file names.
- *
- * For details about the file name format, see SlruFileName().
- */
- bool long_segment_names;
-
/*
* Which sync handler function to use when handing sync requests over to
* the checkpointer. SYNC_HANDLER_NONE to disable fsync (eg pg_notify).
@@ -169,8 +162,7 @@ extern Size SimpleLruShmemSize(int nslots, int nlsns);
extern int SimpleLruAutotuneBuffers(int divisor, int max);
extern void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id,
- int bank_tranche_id, SyncRequestHandler sync_handler,
- bool long_segment_names);
+ int bank_tranche_id, SyncRequestHandler sync_handler);
extern int SimpleLruZeroPage(SlruCtl ctl, int64 pageno);
extern void SimpleLruZeroAndWritePage(SlruCtl ctl, int64 pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int64 pageno, bool write_ok,
diff --git a/src/test/modules/test_slru/t/002_multixact_wraparound.pl b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
index 3793ac1c450..8b4601ab8e1 100644
--- a/src/test/modules/test_slru/t/002_multixact_wraparound.pl
+++ b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
@@ -40,7 +40,7 @@ my $slru_pages_per_segment = $1;
my $multixact_offsets_per_page = $blcksz / 8; # sizeof(MultiXactOffset) == 8
my $segno =
int(0xFFFFFFF8 / $multixact_offsets_per_page / $slru_pages_per_segment);
-my $slru_file = sprintf('%s/pg_multixact/offsets/%04X', $node_pgdata, $segno);
+my $slru_file = sprintf('%s/pg_multixact/offsets/%015X', $node_pgdata, $segno);
open my $fh, ">", $slru_file
or die "could not open \"$slru_file\": $!";
binmode $fh;
@@ -50,8 +50,8 @@ syswrite($fh, "\0" x $bytes_per_seg) == $bytes_per_seg
close $fh;
# remove old file
-unlink("$node_pgdata/pg_multixact/offsets/0000")
- or die "could not unlink \"$node_pgdata/pg_multixact/offsets/0000\": $!";
+unlink("$node_pgdata/pg_multixact/offsets/000000000000000")
+ or die "could not unlink \"$node_pgdata/pg_multixact/offsets/000000000000000\": $!";
# Consume multixids to wrap around. We start at 0xFFFFFFF8, so after
# creating 16 multixacts we should definitely have wrapped around.
diff --git a/src/test/modules/test_slru/test_slru.c b/src/test/modules/test_slru/test_slru.c
index 4dc74e19620..642f1aeb8ca 100644
--- a/src/test/modules/test_slru/test_slru.c
+++ b/src/test/modules/test_slru/test_slru.c
@@ -213,11 +213,6 @@ test_slru_page_precedes_logically(int64 page1, int64 page2)
static void
test_slru_shmem_startup(void)
{
- /*
- * Short segments names are well tested elsewhere so in this test we are
- * focusing on long names.
- */
- const bool long_segment_names = true;
const char slru_dir_name[] = "pg_test_slru";
int test_tranche_id = -1;
int test_buffer_tranche_id = -1;
@@ -247,8 +242,7 @@ test_slru_shmem_startup(void)
TestSlruCtl->PagePrecedes = test_slru_page_precedes_logically;
SimpleLruInit(TestSlruCtl, "TestSLRU",
NUM_TEST_BUFFERS, 0, slru_dir_name,
- test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE,
- long_segment_names);
+ test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE);
}
void
--
2.43.0
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2026-01-06 15:28 Heikki Linnakangas <[email protected]>
parent: Aleksander Alekseev <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Heikki Linnakangas @ 2026-01-06 15:28 UTC (permalink / raw)
To: Aleksander Alekseev <[email protected]>; [email protected]; +Cc: Rustam ALLAKOV <[email protected]>; Michael Paquier <[email protected]>
On 06/01/2026 17:18, Aleksander Alekseev wrote:
> +static void
> +check_slru_segment_filenames(void)
> +{
> + int i;
> + static const char* dirs[] = {
> + "pg_xact",
> + "pg_commit_ts",
> + "pg_multixact/offsets",
> + "pg_multixact/members",
> + "pg_subtrans",
> + "pg_serial",
> + };
> +
> + if(old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
> + return;
> +
> + for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); i++)
> + rename_slru_segments(dirs[i]);
> +}
Since commit bd8d9c9bdf "Widen MultiXactOffset to 64 bits",
"pg_multixact/members" should not be in that list anymore.
Also, it seems misleading that a function called "check_*" doesn't
merely check for things, but renames files. Also, it seems silly to
first copy/link the files with the old short names, and rename them
later. Could we copy/link them with the new long names to begin with?
(No comment on whether this is a good idea in general or the rest of the
patch)
- Heikki
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2026-01-07 14:42 Aleksander Alekseev <[email protected]>
parent: Heikki Linnakangas <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Aleksander Alekseev @ 2026-01-07 14:42 UTC (permalink / raw)
To: [email protected]; +Cc: Heikki Linnakangas <[email protected]>; Rustam ALLAKOV <[email protected]>; Michael Paquier <[email protected]>
Hi Heikki,
> Since commit bd8d9c9bdf "Widen MultiXactOffset to 64 bits",
> "pg_multixact/members" should not be in that list anymore.
I missed this one. Fixed, thanks.
> Also, it seems misleading that a function called "check_*" doesn't
> merely check for things, but renames files.
Fair point. I renamed it to `ensure_long_slru_segment_filenames`.
> Could we copy/link them with the new long names to begin with?
That's an interesting idea.
What I personally don't like about it is the fact that a single
migration will affect the logic of every run of pg_upgrade, even in
the far future, for instances that don't need this migration.
Previously I showed [1] that the entire migration takes little time
(note that we had to migrate pg_multixact/members back then). So I
don't think this optimization is a good idea in the long run, unless
we reach a consensus on the opposite.
[1]: https://www.postgresql.org/message-id/CAJ7c6TPdDSnVR2ZGn-oirfvvFXZghS5PAXYwmtb7_nNps53eEg%40mail.gma...
--
Best regards,
Aleksander Alekseev
Attachments:
[text/x-patch] v8-0001-Always-use-long-SLRU-segment-file-names.patch (16.4K, 2-v8-0001-Always-use-long-SLRU-segment-file-names.patch)
download | inline diff:
From 8223661f9194a76d1d3e09a2fad4ef3cec8f909f Mon Sep 17 00:00:00 2001
From: Aleksander Alekseev <[email protected]>
Date: Wed, 11 Sep 2024 13:17:33 +0300
Subject: [PATCH v8] Always use long SLRU segment file names
PG17 introduced long SLRU segment file names (commit 4ed8f0913bfd). We used
short or long file names depending on SlruCtl->long_segment_names. This commit
refactors SLRU to always use long file names in order to simplify the code.
Author: Aleksander Alekseev <[email protected]>
Reviewed-by: Michael Paquier <[email protected]>
Reviewed-by: Rustam ALLAKOV <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/CAJ7c6TOy7fUW9MuNeOWor3cSFnQg9tgz=mjXHDb94GORtM_Eyg@mail.gmail.com
(!!!) bump catversion and change the corresponding TODO FIXME line in pg_upgrade.h
---
src/backend/access/transam/clog.c | 2 +-
src/backend/access/transam/commit_ts.c | 3 +-
src/backend/access/transam/multixact.c | 6 +-
src/backend/access/transam/slru.c | 71 ++++--------------
src/backend/access/transam/subtrans.c | 2 +-
src/backend/commands/async.c | 2 +-
src/backend/storage/lmgr/predicate.c | 2 +-
src/bin/pg_upgrade/pg_upgrade.c | 73 +++++++++++++++++++
src/bin/pg_upgrade/pg_upgrade.h | 6 ++
src/bin/pg_verifybackup/t/003_corruption.pl | 2 +-
src/include/access/slru.h | 10 +--
.../test_slru/t/002_multixact_wraparound.pl | 6 +-
src/test/modules/test_slru/test_slru.c | 8 +-
13 files changed, 105 insertions(+), 88 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index b5c38bbb162..e46dc13fb5a 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -809,7 +809,7 @@ CLOGShmemInit(void)
XactCtl->PagePrecedes = CLOGPagePrecedes;
SimpleLruInit(XactCtl, "transaction", CLOGShmemBuffers(), CLOG_LSNS_PER_PAGE,
"pg_xact", LWTRANCHE_XACT_BUFFER,
- LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG, false);
+ LWTRANCHE_XACT_SLRU, SYNC_HANDLER_CLOG);
SlruPagePrecedesUnitTests(XactCtl, CLOG_XACTS_PER_PAGE);
}
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 082b564da8f..25774fbc1b9 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -554,8 +554,7 @@ CommitTsShmemInit(void)
SimpleLruInit(CommitTsCtl, "commit_timestamp", CommitTsShmemBuffers(), 0,
"pg_commit_ts", LWTRANCHE_COMMITTS_BUFFER,
LWTRANCHE_COMMITTS_SLRU,
- SYNC_HANDLER_COMMIT_TS,
- false);
+ SYNC_HANDLER_COMMIT_TS);
SlruPagePrecedesUnitTests(CommitTsCtl, COMMIT_TS_XACTS_PER_PAGE);
commitTsShared = ShmemInitStruct("CommitTs shared",
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 3f423636b48..3482b1c16ad 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1736,15 +1736,13 @@ MultiXactShmemInit(void)
"multixact_offset", multixact_offset_buffers, 0,
"pg_multixact/offsets", LWTRANCHE_MULTIXACTOFFSET_BUFFER,
LWTRANCHE_MULTIXACTOFFSET_SLRU,
- SYNC_HANDLER_MULTIXACT_OFFSET,
- false);
+ SYNC_HANDLER_MULTIXACT_OFFSET);
SlruPagePrecedesUnitTests(MultiXactOffsetCtl, MULTIXACT_OFFSETS_PER_PAGE);
SimpleLruInit(MultiXactMemberCtl,
"multixact_member", multixact_member_buffers, 0,
"pg_multixact/members", LWTRANCHE_MULTIXACTMEMBER_BUFFER,
LWTRANCHE_MULTIXACTMEMBER_SLRU,
- SYNC_HANDLER_MULTIXACT_MEMBER,
- true);
+ SYNC_HANDLER_MULTIXACT_MEMBER);
/* doesn't call SimpleLruTruncate() or meet criteria for unit tests */
/* Initialize our shared state struct */
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 549c7e3e64b..18baedd6de6 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -77,41 +77,21 @@
*
* "path" should point to a buffer at least MAXPGPATH characters long.
*
- * If ctl->long_segment_names is true, segno can be in the range [0, 2^60-1].
- * The resulting file name is made of 15 characters, e.g. dir/123456789ABCDEF.
- *
- * If ctl->long_segment_names is false, segno can be in the range [0, 2^24-1].
- * The resulting file name is made of 4 to 6 characters, as of:
- *
- * dir/1234 for [0, 2^16-1]
- * dir/12345 for [2^16, 2^20-1]
- * dir/123456 for [2^20, 2^24-1]
+ * segno can be in the range [0, 2^60-1]. The resulting file name is made
+ * of 15 characters, e.g. dir/123456789ABCDEF.
*/
static inline int
SlruFileName(SlruCtl ctl, char *path, int64 segno)
{
- if (ctl->long_segment_names)
- {
- /*
- * We could use 16 characters here but the disadvantage would be that
- * the SLRU segments will be hard to distinguish from WAL segments.
- *
- * For this reason we use 15 characters. It is enough but also means
- * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
- }
- else
- {
- /*
- * Despite the fact that %04X format string is used up to 24 bit
- * integers are allowed. See SlruCorrectSegmentFilenameLength()
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir,
- (unsigned int) segno);
- }
+ /*
+ * We could use 16 characters here but the disadvantage would be that
+ * the SLRU segments will be hard to distinguish from WAL segments.
+ *
+ * For this reason we use 15 characters. It is enough but also means
+ * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
+ */
+ Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
+ return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->Dir, segno);
}
/*
@@ -251,7 +231,7 @@ SimpleLruAutotuneBuffers(int divisor, int max)
void
SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id, int bank_tranche_id,
- SyncRequestHandler sync_handler, bool long_segment_names)
+ SyncRequestHandler sync_handler)
{
SlruShared shared;
bool found;
@@ -342,7 +322,6 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
*/
ctl->shared = shared;
ctl->sync_handler = sync_handler;
- ctl->long_segment_names = long_segment_names;
ctl->nbanks = nbanks;
strlcpy(ctl->Dir, subdir, sizeof(ctl->Dir));
}
@@ -1773,30 +1752,6 @@ SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage, void *data)
return false; /* keep going */
}
-/*
- * An internal function used by SlruScanDirectory().
- *
- * Returns true if a file with a name of a given length may be a correct
- * SLRU segment.
- */
-static inline bool
-SlruCorrectSegmentFilenameLength(SlruCtl ctl, size_t len)
-{
- if (ctl->long_segment_names)
- return (len == 15); /* see SlruFileName() */
- else
-
- /*
- * Commit 638cf09e76d allowed 5-character lengths. Later commit
- * 73c986adde5 allowed 6-character length.
- *
- * Note: There is an ongoing plan to migrate all SLRUs to 64-bit page
- * numbers, and the corresponding 15-character file names, which may
- * eventually deprecate the support for 4, 5, and 6-character names.
- */
- return (len == 4 || len == 5 || len == 6);
-}
-
/*
* Scan the SimpleLru directory and apply a callback to each file found in it.
*
@@ -1828,7 +1783,7 @@ SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data)
len = strlen(clde->d_name);
- if (SlruCorrectSegmentFilenameLength(ctl, len) &&
+ if ((len == 15) &&
strspn(clde->d_name, "0123456789ABCDEF") == len)
{
segno = strtoi64(clde->d_name, NULL, 16);
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index c0987f43f11..3536971ca7d 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -242,7 +242,7 @@ SUBTRANSShmemInit(void)
SubTransCtl->PagePrecedes = SubTransPagePrecedes;
SimpleLruInit(SubTransCtl, "subtransaction", SUBTRANSShmemBuffers(), 0,
"pg_subtrans", LWTRANCHE_SUBTRANS_BUFFER,
- LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE, false);
+ LWTRANCHE_SUBTRANS_SLRU, SYNC_HANDLER_NONE);
SlruPagePrecedesUnitTests(SubTransCtl, SUBTRANS_XACTS_PER_PAGE);
}
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 40c42f572ed..0dd1a923fc9 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -536,7 +536,7 @@ AsyncShmemInit(void)
NotifyCtl->PagePrecedes = asyncQueuePagePrecedes;
SimpleLruInit(NotifyCtl, "notify", notify_buffers, 0,
"pg_notify", LWTRANCHE_NOTIFY_BUFFER, LWTRANCHE_NOTIFY_SLRU,
- SYNC_HANDLER_NONE, true);
+ SYNC_HANDLER_NONE);
if (!found)
{
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index fe75ead3501..8e97bb35225 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -814,7 +814,7 @@ SerialInit(void)
SimpleLruInit(SerialSlruCtl, "serializable",
serializable_buffers, 0, "pg_serial",
LWTRANCHE_SERIAL_BUFFER, LWTRANCHE_SERIAL_SLRU,
- SYNC_HANDLER_NONE, false);
+ SYNC_HANDLER_NONE);
#ifdef USE_ASSERT_CHECKING
SerialPagePrecedesLogicallyUnitTests();
#endif
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index 2127d297bfe..94964f32eae 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -41,6 +41,7 @@
#include "postgres_fe.h"
+#include <dirent.h>
#include <time.h>
#include "access/multixact.h"
@@ -64,6 +65,8 @@ static void prepare_new_cluster(void);
static void prepare_new_globals(void);
static void create_new_objects(void);
static void copy_xact_xlog_xid(void);
+static void ensure_long_slru_segment_filenames(void);
+static void rename_slru_segments(const char *dirname);
static void set_frozenxids(bool minmxid_only);
static void make_outputdirs(char *pgdata);
static void setup(char *argv0);
@@ -162,6 +165,7 @@ main(int argc, char **argv)
copy_xact_xlog_xid();
set_new_cluster_char_signedness();
+ ensure_long_slru_segment_filenames();
/* New now using xids of the old system */
@@ -902,6 +906,75 @@ copy_xact_xlog_xid(void)
check_ok();
}
+static void
+rename_slru_segments(const char* dirname)
+{
+ DIR *dir;
+ struct dirent *de;
+ int len;
+ int64 segno;
+ char dir_path[MAXPGPATH];
+ char old_path[MAXPGPATH];
+ char new_path[MAXPGPATH];
+
+ prep_status("Renaming SLRU segments in %s", dirname);
+ snprintf(dir_path, sizeof(dir_path), "%s/%s", new_cluster.pgdata, dirname);
+
+ dir = opendir(dir_path);
+ if (dir == NULL)
+ pg_fatal("could not open directory \"%s\": %m", dir_path);
+
+ while (errno = 0, (de = readdir(dir)) != NULL)
+ {
+ /*
+ * ignore '.', '..' and everything else that doesn't look
+ * like an SLRU segment with a short file name
+ */
+
+ len = strlen(de->d_name);
+ if(len != 4 && len != 5 && len != 6)
+ continue;
+
+ if(strspn(de->d_name, "0123456789ABCDEF") != len)
+ continue;
+
+ segno = strtoi64(de->d_name, NULL, 16);
+ snprintf(new_path, MAXPGPATH, "%s/%015llX", dir_path,
+ (long long) segno);
+ snprintf(old_path, MAXPGPATH, "%s/%s", dir_path, de->d_name);
+
+ if (pg_mv_file(old_path, new_path) != 0)
+ pg_fatal("could not rename file \"%s\" to \"%s\": %m",
+ old_path, new_path);
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %m", dir_path);
+
+ if (closedir(dir))
+ pg_fatal("could not close directory \"%s\": %m", dir_path);
+
+ check_ok();
+}
+
+static void
+ensure_long_slru_segment_filenames(void)
+{
+ int i;
+ static const char* dirs[] = {
+ "pg_xact",
+ "pg_commit_ts",
+ "pg_multixact/offsets",
+ "pg_subtrans",
+ "pg_serial",
+ };
+
+ if(old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
+ return;
+
+ for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); i++)
+ rename_slru_segments(dirs[i]);
+}
/*
* set_frozenxids()
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index ec018e4f292..58102e6a483 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -138,6 +138,12 @@ extern char *output_files[];
*/
#define DEFAULT_CHAR_SIGNEDNESS_CAT_VER 202502212
+/*
+ * change of SLRU segment filenames length in PG19
+ * TODO FIXME CHANGE TO THE ACTUAL VALUE BEFORE COMMITTING
+ */
+#define SLRU_SEG_FILENAMES_CHANGE_CAT_VER 202601061
+
/*
* Each relation is represented by a relinfo structure.
*/
diff --git a/src/bin/pg_verifybackup/t/003_corruption.pl b/src/bin/pg_verifybackup/t/003_corruption.pl
index b1d65b8aa0f..4677e9584ca 100644
--- a/src/bin/pg_verifybackup/t/003_corruption.pl
+++ b/src/bin/pg_verifybackup/t/003_corruption.pl
@@ -246,7 +246,7 @@ sub mutilate_extra_tablespace_file
sub mutilate_missing_file
{
my ($backup_path) = @_;
- my $pathname = "$backup_path/pg_xact/0000";
+ my $pathname = "$backup_path/pg_xact/000000000000000";
unlink($pathname) || die "$pathname: $!";
return;
}
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index 4cb8f478fce..541febf86bc 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -116,13 +116,6 @@ typedef struct SlruCtlData
/* Number of banks in this SLRU. */
uint16 nbanks;
- /*
- * If true, use long segment file names. Otherwise, use short file names.
- *
- * For details about the file name format, see SlruFileName().
- */
- bool long_segment_names;
-
/*
* Which sync handler function to use when handing sync requests over to
* the checkpointer. SYNC_HANDLER_NONE to disable fsync (eg pg_notify).
@@ -169,8 +162,7 @@ extern Size SimpleLruShmemSize(int nslots, int nlsns);
extern int SimpleLruAutotuneBuffers(int divisor, int max);
extern void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
const char *subdir, int buffer_tranche_id,
- int bank_tranche_id, SyncRequestHandler sync_handler,
- bool long_segment_names);
+ int bank_tranche_id, SyncRequestHandler sync_handler);
extern int SimpleLruZeroPage(SlruCtl ctl, int64 pageno);
extern void SimpleLruZeroAndWritePage(SlruCtl ctl, int64 pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int64 pageno, bool write_ok,
diff --git a/src/test/modules/test_slru/t/002_multixact_wraparound.pl b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
index 3793ac1c450..8b4601ab8e1 100644
--- a/src/test/modules/test_slru/t/002_multixact_wraparound.pl
+++ b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
@@ -40,7 +40,7 @@ my $slru_pages_per_segment = $1;
my $multixact_offsets_per_page = $blcksz / 8; # sizeof(MultiXactOffset) == 8
my $segno =
int(0xFFFFFFF8 / $multixact_offsets_per_page / $slru_pages_per_segment);
-my $slru_file = sprintf('%s/pg_multixact/offsets/%04X', $node_pgdata, $segno);
+my $slru_file = sprintf('%s/pg_multixact/offsets/%015X', $node_pgdata, $segno);
open my $fh, ">", $slru_file
or die "could not open \"$slru_file\": $!";
binmode $fh;
@@ -50,8 +50,8 @@ syswrite($fh, "\0" x $bytes_per_seg) == $bytes_per_seg
close $fh;
# remove old file
-unlink("$node_pgdata/pg_multixact/offsets/0000")
- or die "could not unlink \"$node_pgdata/pg_multixact/offsets/0000\": $!";
+unlink("$node_pgdata/pg_multixact/offsets/000000000000000")
+ or die "could not unlink \"$node_pgdata/pg_multixact/offsets/000000000000000\": $!";
# Consume multixids to wrap around. We start at 0xFFFFFFF8, so after
# creating 16 multixacts we should definitely have wrapped around.
diff --git a/src/test/modules/test_slru/test_slru.c b/src/test/modules/test_slru/test_slru.c
index 4dc74e19620..642f1aeb8ca 100644
--- a/src/test/modules/test_slru/test_slru.c
+++ b/src/test/modules/test_slru/test_slru.c
@@ -213,11 +213,6 @@ test_slru_page_precedes_logically(int64 page1, int64 page2)
static void
test_slru_shmem_startup(void)
{
- /*
- * Short segments names are well tested elsewhere so in this test we are
- * focusing on long names.
- */
- const bool long_segment_names = true;
const char slru_dir_name[] = "pg_test_slru";
int test_tranche_id = -1;
int test_buffer_tranche_id = -1;
@@ -247,8 +242,7 @@ test_slru_shmem_startup(void)
TestSlruCtl->PagePrecedes = test_slru_page_precedes_logically;
SimpleLruInit(TestSlruCtl, "TestSLRU",
NUM_TEST_BUFFERS, 0, slru_dir_name,
- test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE,
- long_segment_names);
+ test_buffer_tranche_id, test_tranche_id, SYNC_HANDLER_NONE);
}
void
--
2.43.0
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: [PATCH] Refactor SLRU to always use long file names
@ 2026-04-08 10:09 Aleksander Alekseev <[email protected]>
parent: Aleksander Alekseev <[email protected]>
0 siblings, 0 replies; 9+ messages in thread
From: Aleksander Alekseev @ 2026-04-08 10:09 UTC (permalink / raw)
To: [email protected]; +Cc: Heikki Linnakangas <[email protected]>; Rustam ALLAKOV <[email protected]>; Michael Paquier <[email protected]>
Hi,
> > Since commit bd8d9c9bdf "Widen MultiXactOffset to 64 bits",
> > "pg_multixact/members" should not be in that list anymore.
>
> I missed this one. Fixed, thanks.
>
> > Also, it seems misleading that a function called "check_*" doesn't
> > merely check for things, but renames files.
>
> Fair point. I renamed it to `ensure_long_slru_segment_filenames`.
>
> > Could we copy/link them with the new long names to begin with?
>
> That's an interesting idea.
>
> What I personally don't like about it is the fact that a single
> migration will affect the logic of every run of pg_upgrade, even in
> the far future, for instances that don't need this migration.
> Previously I showed [1] that the entire migration takes little time
> (note that we had to migrate pg_multixact/members back then). So I
> don't think this optimization is a good idea in the long run, unless
> we reach a consensus on the opposite.
Rebased.
--
Best regards,
Aleksander Alekseev
Attachments:
[text/x-patch] v9-0001-Always-use-long-SLRU-segment-file-names.patch (14.1K, 2-v9-0001-Always-use-long-SLRU-segment-file-names.patch)
download | inline diff:
From 0275ac047cfe6fced648091aa14f8423fc2383a8 Mon Sep 17 00:00:00 2001
From: Aleksander Alekseev <[email protected]>
Date: Wed, 11 Sep 2024 13:17:33 +0300
Subject: [PATCH v9] Always use long SLRU segment file names
PG17 introduced long SLRU segment file names (commit 4ed8f0913bfd). We used
short or long file names depending on SlruCtl->long_segment_names. This commit
refactors SLRU to always use long file names in order to simplify the code.
Author: Aleksander Alekseev <[email protected]>
Reviewed-by: Michael Paquier <[email protected]>
Reviewed-by: Rustam ALLAKOV <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/CAJ7c6TOy7fUW9MuNeOWor3cSFnQg9tgz=mjXHDb94GORtM_Eyg@mail.gmail.com
(!!!) bump catversion and change the corresponding TODO FIXME line in pg_upgrade.h
---
src/backend/access/transam/clog.c | 1 -
src/backend/access/transam/commit_ts.c | 2 -
src/backend/access/transam/multixact.c | 2 -
src/backend/access/transam/slru.c | 68 +++--------------
src/backend/access/transam/subtrans.c | 1 -
src/backend/commands/async.c | 3 -
src/backend/storage/lmgr/predicate.c | 1 -
src/bin/pg_upgrade/pg_upgrade.c | 73 +++++++++++++++++++
src/bin/pg_upgrade/pg_upgrade.h | 6 ++
src/bin/pg_verifybackup/t/003_corruption.pl | 2 +-
src/include/access/slru.h | 8 --
.../test_slru/t/002_multixact_wraparound.pl | 6 +-
src/test/modules/test_slru/test_slru.c | 6 --
13 files changed, 95 insertions(+), 84 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..eba4ff6edf9 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -812,7 +812,6 @@ CLOGShmemRequest(void *arg)
SimpleLruRequest(.desc = &XactSlruDesc,
.name = "transaction",
.Dir = "pg_xact",
- .long_segment_names = false,
.nslots = CLOGShmemBuffers(),
.nlsns = CLOG_LSNS_PER_PAGE,
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 2625cbf93bf..d9b5f112975 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -551,8 +551,6 @@ CommitTsShmemRequest(void *arg)
SimpleLruRequest(.desc = &CommitTsSlruDesc,
.name = "commit_timestamp",
.Dir = "pg_commit_ts",
- .long_segment_names = false,
-
.nslots = CommitTsShmemBuffers(),
.PagePrecedes = CommitTsPagePrecedes,
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index cb78ba0842d..8037a6ac451 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1785,7 +1785,6 @@ MultiXactShmemRequest(void *arg)
SimpleLruRequest(.desc = &MultiXactOffsetSlruDesc,
.name = "multixact_offset",
.Dir = "pg_multixact/offsets",
- .long_segment_names = false,
.nslots = multixact_offset_buffers,
@@ -1800,7 +1799,6 @@ MultiXactShmemRequest(void *arg)
SimpleLruRequest(.desc = &MultiXactMemberSlruDesc,
.name = "multixact_member",
.Dir = "pg_multixact/members",
- .long_segment_names = true,
.nslots = multixact_member_buffers,
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 47dd52d6749..4a4dff20183 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -80,41 +80,21 @@
*
* "path" should point to a buffer at least MAXPGPATH characters long.
*
- * If ctl->long_segment_names is true, segno can be in the range [0, 2^60-1].
- * The resulting file name is made of 15 characters, e.g. dir/123456789ABCDEF.
- *
- * If ctl->long_segment_names is false, segno can be in the range [0, 2^24-1].
- * The resulting file name is made of 4 to 6 characters, as of:
- *
- * dir/1234 for [0, 2^16-1]
- * dir/12345 for [2^16, 2^20-1]
- * dir/123456 for [2^20, 2^24-1]
+ * segno can be in the range [0, 2^60-1]. The resulting file name is made
+ * of 15 characters, e.g. dir/123456789ABCDEF.
*/
static inline int
SlruFileName(SlruDesc *ctl, char *path, int64 segno)
{
- if (ctl->options.long_segment_names)
- {
- /*
- * We could use 16 characters here but the disadvantage would be that
- * the SLRU segments will be hard to distinguish from WAL segments.
- *
- * For this reason we use 15 characters. It is enough but also means
- * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->options.Dir, segno);
- }
- else
- {
- /*
- * Despite the fact that %04X format string is used up to 24 bit
- * integers are allowed. See SlruCorrectSegmentFilenameLength()
- */
- Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFF));
- return snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->options.Dir,
- (unsigned int) segno);
- }
+ /*
+ * We could use 16 characters here but the disadvantage would be that
+ * the SLRU segments will be hard to distinguish from WAL segments.
+ *
+ * For this reason we use 15 characters. It is enough but also means
+ * that in the future we can't decrease SLRU_PAGES_PER_SEGMENT easily.
+ */
+ Assert(segno >= 0 && segno <= INT64CONST(0xFFFFFFFFFFFFFFF));
+ return snprintf(path, MAXPGPATH, "%s/%015" PRIX64, ctl->options.Dir, segno);
}
/*
@@ -1801,30 +1781,6 @@ SlruScanDirCbDeleteAll(SlruDesc *ctl, char *filename, int64 segpage, void *data)
return false; /* keep going */
}
-/*
- * An internal function used by SlruScanDirectory().
- *
- * Returns true if a file with a name of a given length may be a correct
- * SLRU segment.
- */
-static inline bool
-SlruCorrectSegmentFilenameLength(SlruDesc *ctl, size_t len)
-{
- if (ctl->options.long_segment_names)
- return (len == 15); /* see SlruFileName() */
- else
-
- /*
- * Commit 638cf09e76d allowed 5-character lengths. Later commit
- * 73c986adde5 allowed 6-character length.
- *
- * Note: There is an ongoing plan to migrate all SLRUs to 64-bit page
- * numbers, and the corresponding 15-character file names, which may
- * eventually deprecate the support for 4, 5, and 6-character names.
- */
- return (len == 4 || len == 5 || len == 6);
-}
-
/*
* Scan the SimpleLru directory and apply a callback to each file found in it.
*
@@ -1856,7 +1812,7 @@ SlruScanDirectory(SlruDesc *ctl, SlruScanCallback callback, void *data)
len = strlen(clde->d_name);
- if (SlruCorrectSegmentFilenameLength(ctl, len) &&
+ if ((len == 15) &&
strspn(clde->d_name, "0123456789ABCDEF") == len)
{
segno = strtoi64(clde->d_name, NULL, 16);
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index b79e648b899..916a4fb6c0a 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -246,7 +246,6 @@ SUBTRANSShmemRequest(void *arg)
SimpleLruRequest(.desc = &SubTransSlruDesc,
.name = "subtransaction",
.Dir = "pg_subtrans",
- .long_segment_names = false,
.nslots = SUBTRANSShmemBuffers(),
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index db6a9a6561b..ab4708e7866 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -811,9 +811,6 @@ AsyncShmemRequest(void *arg)
.name = "notify",
.Dir = "pg_notify",
- /* long segment names are used in order to avoid wraparound */
- .long_segment_names = true,
-
.nslots = notify_buffers,
.sync_handler = SYNC_HANDLER_NONE,
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index 899a4ef06e4..1ffbe779237 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -1219,7 +1219,6 @@ PredicateLockShmemRequest(void *arg)
SimpleLruRequest(.desc = &SerialSlruDesc,
.name = "serializable",
.Dir = "pg_serial",
- .long_segment_names = false,
.nslots = serializable_buffers,
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index 2127d297bfe..a1a0d1766f5 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -41,6 +41,7 @@
#include "postgres_fe.h"
+#include <dirent.h>
#include <time.h>
#include "access/multixact.h"
@@ -64,6 +65,8 @@ static void prepare_new_cluster(void);
static void prepare_new_globals(void);
static void create_new_objects(void);
static void copy_xact_xlog_xid(void);
+static void ensure_long_slru_segment_filenames(void);
+static void rename_slru_segments(const char *dirname);
static void set_frozenxids(bool minmxid_only);
static void make_outputdirs(char *pgdata);
static void setup(char *argv0);
@@ -162,6 +165,7 @@ main(int argc, char **argv)
copy_xact_xlog_xid();
set_new_cluster_char_signedness();
+ ensure_long_slru_segment_filenames();
/* New now using xids of the old system */
@@ -902,6 +906,75 @@ copy_xact_xlog_xid(void)
check_ok();
}
+static void
+rename_slru_segments(const char *dirname)
+{
+ DIR *dir;
+ struct dirent *de;
+ int len;
+ int64 segno;
+ char dir_path[MAXPGPATH];
+ char old_path[MAXPGPATH];
+ char new_path[MAXPGPATH];
+
+ prep_status("Renaming SLRU segments in %s", dirname);
+ snprintf(dir_path, sizeof(dir_path), "%s/%s", new_cluster.pgdata, dirname);
+
+ dir = opendir(dir_path);
+ if (dir == NULL)
+ pg_fatal("could not open directory \"%s\": %m", dir_path);
+
+ while (errno = 0, (de = readdir(dir)) != NULL)
+ {
+ /*
+ * ignore '.', '..' and everything else that doesn't look like an SLRU
+ * segment with a short file name
+ */
+
+ len = strlen(de->d_name);
+ if (len != 4 && len != 5 && len != 6)
+ continue;
+
+ if (strspn(de->d_name, "0123456789ABCDEF") != len)
+ continue;
+
+ segno = strtoi64(de->d_name, NULL, 16);
+ snprintf(new_path, MAXPGPATH, "%s/%015" PRIX64, dir_path,
+ (uint64) segno);
+ snprintf(old_path, MAXPGPATH, "%s/%s", dir_path, de->d_name);
+
+ if (pg_mv_file(old_path, new_path) != 0)
+ pg_fatal("could not rename file \"%s\" to \"%s\": %m",
+ old_path, new_path);
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %m", dir_path);
+
+ if (closedir(dir))
+ pg_fatal("could not close directory \"%s\": %m", dir_path);
+
+ check_ok();
+}
+
+static void
+ensure_long_slru_segment_filenames(void)
+{
+ int i;
+ static const char *dirs[] = {
+ "pg_xact",
+ "pg_commit_ts",
+ "pg_multixact/offsets",
+ "pg_subtrans",
+ "pg_serial",
+ };
+
+ if (old_cluster.controldata.cat_ver >= SLRU_SEG_FILENAMES_CHANGE_CAT_VER)
+ return;
+
+ for (i = 0; i < sizeof(dirs) / sizeof(dirs[0]); i++)
+ rename_slru_segments(dirs[i]);
+}
/*
* set_frozenxids()
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 1d767bbda2d..07278dbc914 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -138,6 +138,12 @@ extern char *output_files[];
*/
#define DEFAULT_CHAR_SIGNEDNESS_CAT_VER 202502212
+/*
+ * change of SLRU segment filenames length in PG19
+ * TODO FIXME CHANGE TO THE ACTUAL VALUE BEFORE COMMITTING
+ */
+#define SLRU_SEG_FILENAMES_CHANGE_CAT_VER 202601061
+
/*
* Each relation is represented by a relinfo structure.
*/
diff --git a/src/bin/pg_verifybackup/t/003_corruption.pl b/src/bin/pg_verifybackup/t/003_corruption.pl
index 405ea793b68..37300634bfa 100644
--- a/src/bin/pg_verifybackup/t/003_corruption.pl
+++ b/src/bin/pg_verifybackup/t/003_corruption.pl
@@ -259,7 +259,7 @@ sub mutilate_extra_tablespace_file
sub mutilate_missing_file
{
my ($backup_path) = @_;
- my $pathname = "$backup_path/pg_xact/0000";
+ my $pathname = "$backup_path/pg_xact/000000000000000";
unlink($pathname) || die "$pathname: $!";
return;
}
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index b4adb1789c7..82a802c20d9 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -145,14 +145,6 @@ typedef struct SlruOpts
*/
const char *Dir;
- /*
- * If true, use long segment file names. Otherwise, use short file names.
- *
- * For details about the file name format, see SlruFileName().
- */
- bool long_segment_names;
-
-
/*
* Decide whether a page is "older" for truncation and as a hint for
* evicting pages in LRU order. Return true if every entry of the first
diff --git a/src/test/modules/test_slru/t/002_multixact_wraparound.pl b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
index 3793ac1c450..8b4601ab8e1 100644
--- a/src/test/modules/test_slru/t/002_multixact_wraparound.pl
+++ b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
@@ -40,7 +40,7 @@ my $slru_pages_per_segment = $1;
my $multixact_offsets_per_page = $blcksz / 8; # sizeof(MultiXactOffset) == 8
my $segno =
int(0xFFFFFFF8 / $multixact_offsets_per_page / $slru_pages_per_segment);
-my $slru_file = sprintf('%s/pg_multixact/offsets/%04X', $node_pgdata, $segno);
+my $slru_file = sprintf('%s/pg_multixact/offsets/%015X', $node_pgdata, $segno);
open my $fh, ">", $slru_file
or die "could not open \"$slru_file\": $!";
binmode $fh;
@@ -50,8 +50,8 @@ syswrite($fh, "\0" x $bytes_per_seg) == $bytes_per_seg
close $fh;
# remove old file
-unlink("$node_pgdata/pg_multixact/offsets/0000")
- or die "could not unlink \"$node_pgdata/pg_multixact/offsets/0000\": $!";
+unlink("$node_pgdata/pg_multixact/offsets/000000000000000")
+ or die "could not unlink \"$node_pgdata/pg_multixact/offsets/000000000000000\": $!";
# Consume multixids to wrap around. We start at 0xFFFFFFF8, so after
# creating 16 multixacts we should definitely have wrapped around.
diff --git a/src/test/modules/test_slru/test_slru.c b/src/test/modules/test_slru/test_slru.c
index 40efffdbf62..d4b696d10ff 100644
--- a/src/test/modules/test_slru/test_slru.c
+++ b/src/test/modules/test_slru/test_slru.c
@@ -237,12 +237,6 @@ test_slru_shmem_request(void *arg)
.name = "TestSLRU",
.Dir = TestSlruDir,
- /*
- * Short segments names are well tested elsewhere so in this test we are
- * focusing on long names.
- */
- .long_segment_names = true,
-
.nslots = NUM_TEST_BUFFERS,
.nlsns = 0,
--
2.43.0
^ permalink raw reply [nested|flat] 9+ messages in thread
end of thread, other threads:[~2026-04-08 10:09 UTC | newest]
Thread overview: 9+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2025-01-15 12:42 Re: [PATCH] Refactor SLRU to always use long file names Aleksander Alekseev <[email protected]>
2025-02-25 14:18 ` Aleksander Alekseev <[email protected]>
2025-03-28 20:27 ` Rustam ALLAKOV <[email protected]>
2025-04-03 14:25 ` Aleksander Alekseev <[email protected]>
2025-08-13 11:54 ` Aleksander Alekseev <[email protected]>
2026-01-06 15:18 ` Aleksander Alekseev <[email protected]>
2026-01-06 15:28 ` Heikki Linnakangas <[email protected]>
2026-01-07 14:42 ` Aleksander Alekseev <[email protected]>
2026-04-08 10:09 ` Aleksander Alekseev <[email protected]>
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