Horton

RE: Statistics Import and Export

Shinoda, Noriyoshi <noriyoshi.shinoda@hpe.com>

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From: "Shinoda, Noriyoshi (SXD Japan FSIP)" <noriyoshi.shinoda@hpe.com>
To: Corey Huinker <corey.huinker@gmail.com>, Jeff Davis <pgsql@j-davis.com>
Cc: jian he <jian.universality@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Bruce Momjian <bruce@momjian.us>, Tom Lane <tgl@sss.pgh.pa.us>, Nathan Bossart <nathandbossart@gmail.com>, "Magnus Hagander" <magnus@hagander.net>, Stephen Frost <sfrost@snowman.net>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, Peter Smith <smithpb2250@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, "alvherre@alvh.no-ip.org" <alvherre@alvh.no-ip.org>
Date: 2024-10-22T00:50:56Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Change pg_dump default for statistics export.

  2. pg_dump: Adjust reltuples from 0 to -1 for dumps of older versions.

  3. vacuumdb: Don't skip empty relations in --missing-stats-only mode.

  4. pg_dump: Fix query for gathering attribute stats on older versions.

  5. Prevent redeclaration of typedef TocEntry.

  6. Remove unused function parameters in pg_backup_archiver.c.

  7. pg_dump: Retrieve attribute statistics in batches.

  8. pg_dump: Reduce memory usage of dumps with statistics.

  9. Skip second WriteToc() call for custom-format dumps without data.

  10. Add relallfrozen to pg_dump statistics.

  11. Matview statistics depend on matview data.

  12. Add pg_dump --with-{schema|data|statistics} options.

  13. Stats: use schemaname/relname instead of regclass.

  14. CREATE INDEX: do update index stats if autovacuum=off.

  15. Don't convert to and from floats in pg_dump.

  16. CREATE INDEX: don't update table stats if autovacuum=off.

  17. Organize and deduplicate statistics import tests.

  18. Address stats export review comments.

  19. Address stats import review comments.

  20. Add relallfrozen to pg_class

  21. Fix pg_strtof() to not crash on NULL endptr.

  22. Use attnum to identify index columns in pg_restore_attribute_stats().

  23. pg_dump: prepare attribute stats query.

  24. Avoid unnecessary relation stats query in pg_dump.

  25. Remove redundant pg_set_*_stats() variants.

  26. Do not use in-place updates for statistics import.

  27. Fix confusion about data type of pg_class.relpages and relallvisible.

  28. Documentation fixups for dumping statistics.

  29. Trial fix for old cross-version upgrades.

  30. Transfer statistics during pg_upgrade.

  31. Lock table in ShareUpdateExclusive when importing index stats.

  32. Use in-place updates for pg_restore_relation_stats().

  33. Improve error message for replication of generated columns.

  34. pg_dump: Add dumpSchema and dumpData derivative flags.

  35. Disallow modifying statistics on system columns.

  36. Add missing CommandCounterIncrement() in stats import functions.

  37. Add functions pg_restore_relation_stats(), pg_restore_attribute_stats().

  38. Documentation fixup.

  39. Add functions pg_set_attribute_stats() and pg_clear_attribute_stats().

  40. Change pg_*_relation_stats() functions to return type to void.

  41. Disable autovacuum for tables in stats import tests.

  42. Allow pg_set_relation_stats() to set relpages to -1.

  43. Fixup for pg_set_relation_stats().

  44. Create functions pg_set_relation_stats, pg_clear_relation_stats.

  45. Add memory/disk usage for Window aggregate nodes in EXPLAIN.

  46. Improve performance of dumpSequenceData().

  47. Add INJECTION_POINT_CACHED() to run injection points directly from cache

  48. Improve performance of binary_upgrade_set_pg_class_oids().

  49. Improve assertion in mdwritev()

  50. CREATE INDEX: do not update stats during binary upgrade.

  51. Redefine pg_class.reltuples to be -1 before the first VACUUM or ANALYZE.

Attachments

> 1. Allow relpages to be set to -1 (partitioned tables with partitions have this value after ANALYZE).
> 2. Turn off autovacuum on tables (where possible) if they are going to be the target of pg_set_relation_stats().
> 3. Allow pg_set_relation_stats to continue past an out-of-range detection on one attribute, rather than immediately returning false

Thank you for developing this feature.
If the relpages option contains -1 only for partitioned tables, shouldn't pg_set_relation_stats restrict the values that can be
specified by table type? The attached patch limits the value to -1 or more if the target
is a partition table, and 0 or more otherwise.
Changing relpages to -1 on a non-partitioned table seems to significantly change the execution plan.

---
postgres=> EXPLAIN (COSTS OFF) SELECT * FROM data1 WHERE c1=1000;
              QUERY PLAN
--------------------------------------
Index Scan using data1_pkey on data1
   Index Cond: (c1 = 1000)
(2 rows)

postgres=> SELECT pg_set_relation_stats('data1', relpages=>-1);
pg_set_relation_stats
-----------------------
t
(1 row)

postgres=> EXPLAIN (COSTS OFF) SELECT * FROM data1 WHERE c1=1000;
              QUERY PLAN
---------------------------------------
Bitmap Heap Scan on data1
   Recheck Cond: (c1 = 1000)
   ->  Bitmap Index Scan on data1_pkey
         Index Cond: (c1 = 1000)
(4 rows)
---

Regards,
Noriyoshi Shinoda

From: Corey Huinker <corey.huinker@gmail.com>
Sent: Saturday, October 19, 2024 10:00 AM
To: Jeff Davis <pgsql@j-davis.com>
Cc: Shinoda, Noriyoshi (SXD Japan FSIP) <noriyoshi.shinoda@hpe.com>; jian he <jian.universality@gmail.com>; Matthias van de Meent <boekewurm+postgres@gmail.com>; Bruce Momjian <bruce@momjian.us>; Tom Lane <tgl@sss.pgh.pa.us>; Nathan Bossart <nathandbossart@gmail.com>; Magnus Hagander <magnus@hagander.net>; Stephen Frost <sfrost@snowman.net>; Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>; Peter Smith <smithpb2250@gmail.com>; PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>; alvherre@alvh.no-ip.org
Subject: Re: Statistics Import and Export



Patch that allows relation_statistics_update to continue after one failed stat (0001) attached, along with bool->void change (0002).

Once more, with feeling: