postgres/contrib
Michael Paquier 684a745f55 pgstattuple: Improve reports generated for indexes (hash, gist, btree)
pgstattuple checks the state of the pages retrieved for gist and hash
using some check functions from each index AM, respectively
gistcheckpage() and _hash_checkpage().  When these are called, they
would fail when bumping on data that is found as incorrect (like opaque
area size not matching, or empty pages), contrary to btree that simply
discards these cases and continues to aggregate data.

Zero pages can happen after a crash, with these AMs being able to do an
internal cleanup when these are seen.  Also, sporadic failures are
annoying when doing for example a large-scale diagnostic query based on
pgstattuple with a join of pg_class, as it forces one to use tricks like
quals to discard hash or gist indexes, or use a PL wrapper able to catch
errors.

This commit changes the reports generated for btree, gist and hash to
be more user-friendly;
- When seeing an empty page, report it as free space.  This new rule
applies to gist and hash, and already applied to btree.
- For btree, a check based on the size of BTPageOpaqueData is added.
- For gist indexes, gistcheckpage() is not called anymore, replaced by a
check based on the size of GISTPageOpaqueData.
- For hash indexes, instead of _hash_getbuf_with_strategy(), use a
direct call to ReadBufferExtended(), coupled with a check based on
HashPageOpaqueData.  The opaque area size check was already used.
- Pages that do not match these criterias are discarded from the stats
reports generated.

There have been a couple of bug reports over the years that complained
about the current behavior for hash and gist, as being not that useful,
with nothing being done about it.  Hence this change is backpatched down
to v13.

Reported-by: Noah Misch <noah@leadboat.com>
Author: Nitin Motiani <nitinmotiani@google.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Discussion: https://postgr.es/m/CAH5HC95gT1J3dRYK4qEnaywG8RqjbwDdt04wuj8p39R=HukayA@mail.gmail.com
Backpatch-through: 13
2025-10-02 11:07:30 +09:00
..
amcheck Fix various incorrect filename references 2025-09-22 13:33:17 +12:00
auth_delay Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
auto_explain Allow resetting unknown custom GUCs with reserved prefixes. 2025-08-01 16:52:11 -05:00
basebackup_to_shell meson: Increase minimum version to 0.57.2 2025-07-02 11:14:53 +02:00
basic_archive Remove translation marker from libpq-be-fe-helpers.h. 2025-07-22 22:08:36 +09:00
bloom Remove unneeded casts of BufferGetPage() result 2025-08-29 07:18:29 +02:00
bool_plperl Fix erroneous construction of functions' dependencies on transforms. 2025-04-07 13:31:37 -04:00
btree_gin Add more cross-type comparisons to contrib/btree_gin. 2025-07-03 16:30:38 -04:00
btree_gist Do a tiny bit of header file maintenance 2025-09-30 12:28:29 +02:00
citext Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
cube Allow redeclaration of typedef yyscan_t 2025-09-12 08:16:00 +02:00
dblink postgres_fdw and dblink should check if backend has MyProcPort 2025-08-08 19:34:31 +02:00
dict_int Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
dict_xsyn Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
earthdistance Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
file_fdw Keep track of what RTIs a Result node is scanning. 2025-09-23 09:07:55 -04:00
fuzzystrmatch Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
hstore Fix varatt versus Datum type confusions 2025-08-05 12:11:36 +02:00
hstore_plperl Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
hstore_plpython Remove circular #include's between plpython.h and plpy_util.h. 2025-04-27 11:43:02 -04:00
intagg Update copyright for 2025 2025-01-01 11:21:55 -05:00
intarray Track the maximum possible frequency of non-MCE array elements. 2025-09-20 14:48:16 -04:00
isn Fix various incorrect filename references 2025-09-22 13:33:17 +12:00
jsonb_plperl Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
jsonb_plpython Remove circular #include's between plpython.h and plpy_util.h. 2025-04-27 11:43:02 -04:00
lo Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
ltree Mop-up for Datum conversion cleanups. 2025-08-08 18:44:57 -04:00
ltree_plpython Remove circular #include's between plpython.h and plpy_util.h. 2025-04-27 11:43:02 -04:00
oid2name Update copyright for 2025 2025-01-01 11:21:55 -05:00
pageinspect Add missing Datum conversions 2025-08-08 22:06:57 +02:00
passwordcheck Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
pg_buffercache Add CHECK_FOR_INTERRUPTS in contrib/pg_buffercache functions. 2025-08-19 12:11:42 -07:00
pg_freespacemap Prevent assertion failure in contrib/pg_freespacemap. 2025-03-27 13:20:23 -04:00
pg_logicalinspect Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
pg_overexplain Keep track of what RTIs a Result node is scanning. 2025-09-23 09:07:55 -04:00
pg_prewarm bufmgr: Remove freelist, always use clock-sweep 2025-09-05 12:25:59 -04:00
pg_stat_statements Remove whitespace in comment of pg_stat_statements.c 2025-09-12 09:56:10 +09:00
pg_surgery Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
pg_trgm Put "excludeOnly" GIN scan keys at the end of the scankey array. 2025-08-26 12:08:57 -04:00
pg_visibility read_stream: Introduce and use optional batchmode support 2025-03-30 18:36:41 -04:00
pg_walinspect Standardize LSN formatting by zero padding 2025-07-07 13:57:43 +02:00
pgcrypto Revert "Make some use of anonymous unions [pgcrypto]" 2025-09-30 13:12:16 +02:00
pgrowlocks Add missing Datum conversions 2025-08-08 22:06:57 +02:00
pgstattuple pgstattuple: Improve reports generated for indexes (hash, gist, btree) 2025-10-02 11:07:30 +09:00
postgres_fdw Keep track of what RTIs a Result node is scanning. 2025-09-23 09:07:55 -04:00
seg Allow redeclaration of typedef yyscan_t 2025-09-12 08:16:00 +02:00
sepgsql Avoid including commands/dbcommands.h in so many places 2025-08-28 12:39:04 +02:00
spi Use pg_ascii_tolower()/pg_ascii_toupper() where appropriate. 2025-07-01 07:24:23 -07:00
sslinfo Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
start-scripts Remove gratuitous references to postmaster program 2023-01-26 10:48:32 +01:00
tablefunc Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
tcn Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
test_decoding Make some use of anonymous unions [reorderbuffer xact_time] 2025-09-30 12:35:50 +02:00
tsm_system_rows Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
tsm_system_time Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
unaccent Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
uuid-ossp Use PG_MODULE_MAGIC_EXT in our installable shared libraries. 2025-03-26 11:11:02 -04:00
vacuumlo Update copyright for 2025 2025-01-01 11:21:55 -05:00
xml2 Fix up misuse of "volatile" in contrib/xml2. 2025-07-08 17:00:34 -04:00
contrib-global.mk
Makefile pg_overexplain: Additional EXPLAIN options for debugging. 2025-03-26 13:52:21 -04:00
meson.build pg_overexplain: Additional EXPLAIN options for debugging. 2025-03-26 13:52:21 -04:00
README

The PostgreSQL contrib tree
---------------------------

This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly
because they address a limited audience or are too experimental to be
part of the main source tree.  This does not preclude their
usefulness.

User documentation for each module appears in the main SGML
documentation.

When building from the source distribution, these modules are not
built automatically, unless you build the "world" target.  You can
also build and install them all by running "make all" and "make
install" in this directory; or to build and install just one selected
module, do the same in that module's subdirectory.

Some directories supply new user-defined functions, operators, or
types.  To make use of one of these modules, after you have installed
the code you need to register the new SQL objects in the database
system by executing a CREATE EXTENSION command.  In a fresh database,
you can simply do

    CREATE EXTENSION module_name;

See the PostgreSQL documentation for more information about this
procedure.