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* [PATCH 6/8] Add default_toast_compression GUC
@ 2021-03-10 08:35 Dilip Kumar <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Dilip Kumar @ 2021-03-10 08:35 UTC (permalink / raw)
Justin Pryzby and Dilip Kumar
---
src/backend/access/common/toast_compression.c | 46 +++++++++++++++++++
src/backend/access/common/tupdesc.c | 2 +-
src/backend/bootstrap/bootstrap.c | 2 +-
src/backend/commands/tablecmds.c | 8 ++--
src/backend/utils/misc/guc.c | 12 +++++
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/include/access/toast_compression.h | 22 ++++++++-
src/test/regress/expected/compression.out | 16 +++++++
src/test/regress/expected/compression_1.out | 19 ++++++++
src/test/regress/sql/compression.sql | 8 ++++
10 files changed, 128 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/common/toast_compression.c b/src/backend/access/common/toast_compression.c
index 3463b42438..e33f92687c 100644
--- a/src/backend/access/common/toast_compression.c
+++ b/src/backend/access/common/toast_compression.c
@@ -55,6 +55,9 @@ const CompressionRoutine toast_compression[] =
}
};
+/* Compile-time default */
+char *default_toast_compression = DEFAULT_TOAST_COMPRESSION;
+
/*
* pglz_cmcompress - compression routine for pglz compression method
*
@@ -306,3 +309,46 @@ GetCompressionRoutines(char method)
{
return &toast_compression[CompressionMethodToId(method)];
}
+
+/* check_hook: validate new default_toast_compression */
+bool
+check_default_toast_compression(char **newval, void **extra, GucSource source)
+{
+ if (**newval == '\0')
+ {
+ GUC_check_errdetail("%s cannot be empty.",
+ "default_toast_compression");
+ return false;
+ }
+
+ if (strlen(*newval) >= NAMEDATALEN)
+ {
+ GUC_check_errdetail("%s is too long (maximum %d characters).",
+ "default_toast_compression", NAMEDATALEN - 1);
+ return false;
+ }
+
+ if (!CompressionMethodIsValid(CompressionNameToMethod(*newval)))
+ {
+ /*
+ * When source == PGC_S_TEST, don't throw a hard error for a
+ * nonexistent compression method, only a NOTICE. See comments in
+ * guc.h.
+ */
+ if (source == PGC_S_TEST)
+ {
+ ereport(NOTICE,
+ (errcode(ERRCODE_UNDEFINED_OBJECT),
+ errmsg("compression method \"%s\" does not exist",
+ *newval)));
+ }
+ else
+ {
+ GUC_check_errdetail("Compression method \"%s\" does not exist.",
+ *newval);
+ return false;
+ }
+ }
+
+ return true;
+}
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index a66d1113db..362a371a6c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -668,7 +668,7 @@ TupleDescInitEntry(TupleDesc desc,
att->attcollation = typeForm->typcollation;
if (IsStorageCompressible(typeForm->typstorage))
- att->attcompression = DefaultCompressionMethod;
+ att->attcompression = GetDefaultToastCompression();
else
att->attcompression = InvalidCompressionMethod;
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index af0c0aa77e..9be0841d08 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -733,7 +733,7 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
attrtypes[attnum]->atttypmod = -1;
attrtypes[attnum]->attislocal = true;
if (IsStorageCompressible(attrtypes[attnum]->attstorage))
- attrtypes[attnum]->attcompression = DefaultCompressionMethod;
+ attrtypes[attnum]->attcompression = GetDefaultToastCompression();
else
attrtypes[attnum]->attcompression = InvalidCompressionMethod;
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index e20dd5f63c..a0d2af0cde 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -11971,7 +11971,7 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
if (!IsStorageCompressible(tform->typstorage))
attTup->attcompression = InvalidCompressionMethod;
else if (!CompressionMethodIsValid(attTup->attcompression))
- attTup->attcompression = DefaultCompressionMethod;
+ attTup->attcompression = GetDefaultToastCompression();
}
else
attTup->attcompression = InvalidCompressionMethod;
@@ -17847,9 +17847,9 @@ GetAttributeCompression(Form_pg_attribute att, char *compression)
/* fallback to default compression if it's not specified */
if (compression == NULL)
- return DefaultCompressionMethod;
-
- cmethod = CompressionNameToMethod(compression);
+ cmethod = GetDefaultToastCompression();
+ else
+ cmethod = CompressionNameToMethod(compression);
return cmethod;
}
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 953837085f..e59ed5b214 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -33,6 +33,7 @@
#include "access/gin.h"
#include "access/rmgr.h"
#include "access/tableam.h"
+#include "access/toast_compression.h"
#include "access/transam.h"
#include "access/twophase.h"
#include "access/xact.h"
@@ -3915,6 +3916,17 @@ static struct config_string ConfigureNamesString[] =
check_default_table_access_method, NULL, NULL
},
+ {
+ {"default_toast_compression", PGC_USERSET, CLIENT_CONN_STATEMENT,
+ gettext_noop("Sets the default compression for new columns."),
+ NULL,
+ GUC_IS_NAME
+ },
+ &default_toast_compression,
+ DEFAULT_TOAST_COMPRESSION,
+ check_default_toast_compression, NULL, NULL
+ },
+
{
{"default_tablespace", PGC_USERSET, CLIENT_CONN_STATEMENT,
gettext_noop("Sets the default tablespace to create tables and indexes in."),
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f46c2dd7a8..7d7a433dcc 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -659,6 +659,7 @@
#temp_tablespaces = '' # a list of tablespace names, '' uses
# only default tablespace
#default_table_access_method = 'heap'
+#default_toast_compression = 'pglz' # 'pglz' or 'lz4'
#check_function_bodies = on
#default_transaction_isolation = 'read committed'
#default_transaction_read_only = off
diff --git a/src/include/access/toast_compression.h b/src/include/access/toast_compression.h
index 38800cb97a..e9d9ce5634 100644
--- a/src/include/access/toast_compression.h
+++ b/src/include/access/toast_compression.h
@@ -15,6 +15,14 @@
#include "postgres.h"
+#include "utils/guc.h"
+
+/* default compression method if not specified. */
+#define DEFAULT_TOAST_COMPRESSION "pglz"
+
+/* GUCs */
+extern char *default_toast_compression;
+
/*
* Built-in compression methods. pg_attribute will store this in the
* attcompression column.
@@ -36,8 +44,6 @@ typedef enum CompressionId
LZ4_COMPRESSION_ID = 1
} CompressionId;
-/* use default compression method if it is not specified. */
-#define DefaultCompressionMethod PGLZ_COMPRESSION
#define IsValidCompression(cm) ((cm) != InvalidCompressionMethod)
#define IsStorageCompressible(storage) ((storage) != TYPSTORAGE_PLAIN && \
@@ -67,6 +73,8 @@ typedef struct CompressionRoutine
extern char CompressionNameToMethod(char *compression);
extern const CompressionRoutine *GetCompressionRoutines(char method);
+extern bool check_default_toast_compression(char **newval, void **extra,
+ GucSource source);
/*
* CompressionMethodToId - Convert compression method to compression id.
@@ -115,5 +123,15 @@ GetCompressionMethodName(char method)
return GetCompressionRoutines(method)->cmname;
}
+/*
+ * GetDefaultToastCompression -- get the current toast compression
+ *
+ * This exists to hide the use of the default_toast_compression GUC variable.
+ */
+static inline char
+GetDefaultToastCompression(void)
+{
+ return CompressionNameToMethod(default_toast_compression);
+}
#endif /* TOAST_COMPRESSION_H */
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 6981d580dc..9ddffc8b18 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -231,6 +231,22 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
NOTICE: merging column "f1" with inherited definition
ERROR: column "f1" has a compression method conflict
DETAIL: pglz versus lz4
+-- test default_toast_compression GUC
+SET default_toast_compression = '';
+ERROR: invalid value for parameter "default_toast_compression": ""
+DETAIL: default_toast_compression cannot be empty.
+SET default_toast_compression = 'I do not exist compression';
+ERROR: invalid value for parameter "default_toast_compression": "I do not exist compression"
+DETAIL: Compression method "I do not exist compression" does not exist.
+SET default_toast_compression = 'lz4';
+DROP TABLE cmdata2;
+CREATE TABLE cmdata2 (f1 text);
+\d+ cmdata2
+ Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1 | text | | | | extended | lz4 | |
+
-- check data is ok
SELECT length(f1) FROM cmdata;
length
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 893c18c7fa..03a7f46554 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -237,6 +237,25 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
NOTICE: merging column "f1" with inherited definition
ERROR: column "f1" has a compression method conflict
DETAIL: pglz versus lz4
+-- test default_toast_compression GUC
+SET default_toast_compression = '';
+ERROR: invalid value for parameter "default_toast_compression": ""
+DETAIL: default_toast_compression cannot be empty.
+SET default_toast_compression = 'I do not exist compression';
+ERROR: invalid value for parameter "default_toast_compression": "I do not exist compression"
+DETAIL: Compression method "I do not exist compression" does not exist.
+SET default_toast_compression = 'lz4';
+ERROR: unsupported LZ4 compression method
+DETAIL: This functionality requires the server to be built with lz4 support.
+HINT: You need to rebuild PostgreSQL using --with-lz4.
+DROP TABLE cmdata2;
+CREATE TABLE cmdata2 (f1 text);
+\d+ cmdata2
+ Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1 | text | | | | extended | pglz | |
+
-- check data is ok
SELECT length(f1) FROM cmdata;
length
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index b085c9fbd9..6c9b24f1f7 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -103,6 +103,14 @@ SELECT pg_column_compression(f1) FROM cmpart;
CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
+-- test default_toast_compression GUC
+SET default_toast_compression = '';
+SET default_toast_compression = 'I do not exist compression';
+SET default_toast_compression = 'lz4';
+DROP TABLE cmdata2;
+CREATE TABLE cmdata2 (f1 text);
+\d+ cmdata2
+
-- check data is ok
SELECT length(f1) FROM cmdata;
SELECT length(f1) FROM cmdata1;
--
2.17.0
--cvVnyQ+4j833TQvp
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="0007-Alter-table-set-compression.patch"
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: allowing extensions to control planner behavior
@ 2024-08-28 23:15 Jeff Davis <[email protected]>
2024-08-28 23:25 ` Re: allowing extensions to control planner behavior Tom Lane <[email protected]>
0 siblings, 1 reply; 4+ messages in thread
From: Jeff Davis @ 2024-08-28 23:15 UTC (permalink / raw)
To: Robert Haas <[email protected]>; +Cc: pgsql-hackers
On Wed, 2024-08-28 at 16:35 -0400, Robert Haas wrote:
> On Wed, Aug 28, 2024 at 4:29 PM Jeff Davis <[email protected]> wrote:
> > Preserving a path for the right amount of time seems like the
> > primary
> > challenge for most of the use cases you raised (removing paths is
> > easier than resurrecting one that was pruned too early). If we try
> > to
> > keep a path around, that implies that we need to keep parent paths
> > around too, which leads to an explosion if we aren't careful.
> >
> > But we already solved all of that for pathkeys. We keep the paths
> > around if there's a reason to (a useful pathkey) and there's not
> > some
> > other cheaper path that also satisfies the same reason.
>
> But we've already solved it for this case, too. This is exactly what
> incrementing disabled_nodes does.
Hints are often described as something positive: use this index, use a
hash join here, etc. Trying to force a positive thing by adding
negative attributes to everything else is awkward. We've all had the
experience where we disable one plan type hoping for a good plan, and
we end up getting a different crazy plan that we didn't expect, and
need to disable a few more plan types.
Beyond awkwardness, one case where it matters is the interaction
between an extension that provides hints and an extension that offers a
CustomScan. How is the hints extension supposed to disable a path it
doesn't know about?
Regards,
Jeff Davis
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: allowing extensions to control planner behavior
2024-08-28 23:15 Re: allowing extensions to control planner behavior Jeff Davis <[email protected]>
@ 2024-08-28 23:25 ` Tom Lane <[email protected]>
2024-08-29 00:28 ` Re: allowing extensions to control planner behavior Michael Paquier <[email protected]>
0 siblings, 1 reply; 4+ messages in thread
From: Tom Lane @ 2024-08-28 23:25 UTC (permalink / raw)
To: Jeff Davis <[email protected]>; +Cc: Robert Haas <[email protected]>; pgsql-hackers
Jeff Davis <[email protected]> writes:
> Beyond awkwardness, one case where it matters is the interaction
> between an extension that provides hints and an extension that offers a
> CustomScan. How is the hints extension supposed to disable a path it
> doesn't know about?
This does not seem remarkably problematic to me, given Robert's
proposal of a bitmask of allowed plan types per RelOptInfo.
You just do something like
rel->allowed_plan_types = DESIRED_PLAN_TYPE;
The names of the bits you aren't setting are irrelevant to you.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: allowing extensions to control planner behavior
2024-08-28 23:15 Re: allowing extensions to control planner behavior Jeff Davis <[email protected]>
2024-08-28 23:25 ` Re: allowing extensions to control planner behavior Tom Lane <[email protected]>
@ 2024-08-29 00:28 ` Michael Paquier <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Michael Paquier @ 2024-08-29 00:28 UTC (permalink / raw)
To: Tom Lane <[email protected]>; +Cc: Jeff Davis <[email protected]>; Robert Haas <[email protected]>; pgsql-hackers
On Wed, Aug 28, 2024 at 07:25:59PM -0400, Tom Lane wrote:
> Jeff Davis <[email protected]> writes:
> > Beyond awkwardness, one case where it matters is the interaction
> > between an extension that provides hints and an extension that offers a
> > CustomScan. How is the hints extension supposed to disable a path it
> > doesn't know about?
pg_hint_plan documents its hints here:
https://pg-hint-plan.readthedocs.io/en/master/hint_list.html#hint-list
Hmm. I think that we should be careful to check that this works
correctly with pg_hint_plan, at least. The module goes through a lot
of tweaks and is a can of worms in terms of plan adjustments because
we can only rely on the planner hook to do the whole work. This leads
to a lot of frustration for users because each feature somebody asks
for leads to just more tweaks to apply on the paths.
The bullet list sent here sounds pretty good to me:
https://www.postgresql.org/message-id/[email protected]
> This does not seem remarkably problematic to me, given Robert's
> proposal of a bitmask of allowed plan types per RelOptInfo.
> You just do something like
>
> rel->allowed_plan_types = DESIRED_PLAN_TYPE;
>
> The names of the bits you aren't setting are irrelevant to you.
For the types of scans to use, that would be OK. The module has a
feature where one can also have a regex to match for an index, and
the module is very funky with inheritance and partitioned tables.
How does that help if using a Leading hint to force a join order?
That's something people like a lot. But perhaps that's just the part
of upthread where we'd need a extra hook? I am not completely sure to
get the portion of the proposal for that. add_paths_to_joinrel() has
been mentioned, and there is set_join_pathlist_hook already there.
--
Michael
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^ permalink raw reply [nested|flat] 4+ messages in thread
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2021-03-10 08:35 [PATCH 6/8] Add default_toast_compression GUC Dilip Kumar <[email protected]>
2024-08-28 23:15 Re: allowing extensions to control planner behavior Jeff Davis <[email protected]>
2024-08-28 23:25 ` Re: allowing extensions to control planner behavior Tom Lane <[email protected]>
2024-08-29 00:28 ` Re: allowing extensions to control planner behavior Michael Paquier <[email protected]>
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