Horton

Re: Statistics Import and Export

jian he <jian.universality@gmail.com>

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From: jian he <jian.universality@gmail.com>
To: Corey Huinker <corey.huinker@gmail.com>
Cc: Jeff Davis <pgsql@j-davis.com>, Nathan Bossart <nathandbossart@gmail.com>, Bruce Momjian <bruce@momjian.us>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, 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
Date: 2025-01-16T14:43:24Z
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.

On Thu, Jan 16, 2025 at 4:56 AM Corey Huinker <corey.huinker@gmail.com> wrote:
>>
> Attached is just the pg_dump stuff, and only for relation/attribute stats. The extended stats and vacuumdb work will be in their own threads going forward.

I didn't follow this thread actively,
so if the following issue is already addressed, please forgive me.


pg_dump --dbname=src2 --table=tenk1 --statistics-only --verbose > x.sql
there no pg_restore_attribute_stats, pg_restore_relation_stats there
for table tenk1.
There aren't any statistics, should there be?

also should
pg_dump --dbname=src2 --no-data --no-schema --table=tenk1
dump the statistics? currently seems no.

in doc/src/sgml/ref/pg_dump.sgml
there are six options to control the main output now.
--schema-only, --statistics-only, --data-only,
--no-schema, --no-data, --no-statistics
maybe we need spare one paragraph to explain the default behavior,
and also have an example on it?


pg_dump --dbname=src2 --table=tenk1 --verbose > 1.sql
seems the statistics dump (pg_restore_attribute_stats) is ordered by
attribute name.
should it make more sense to order by attnum?


getRelationStatistics
typedef struct _relStatsInfo
{
    DumpableObject    dobj;
    char            relkind;        /* 'r', 'v', 'c', etc */
    bool            postponed_def;
} RelStatsInfo;
comment /* 'r', 'v', 'c', etc */
Is it wrong?  there is no relkind='c'.
field postponed_def really deserves a comment.


we also need change
enum dbObjectTypePriorities
static const int dbObjectTypePriority[]
?


in dumpRelationStats, we can add Assert on it.
    if (!fout->dopt->dumpStatistics)
        return;
Assert(dobj->dump & DUMP_COMPONENT_STATISTICS);


I found out the owner's info is missing in the dumped content.
for example, the line "Name: STATISTICS DATA tenk1_pkey;" missing owner info.
not sure this is intended?

--
-- Name: tenk1 tenk1_pkey; Type: CONSTRAINT; Schema: public; Owner: jian
--
ALTER TABLE ONLY public.tenk1
    ADD CONSTRAINT tenk1_pkey PRIMARY KEY (unique1);
--
-- Name: STATISTICS DATA tenk1_pkey; Type: STATISTICS DATA; Schema:
public; Owner: -
--
SELECT * FROM pg_catalog.pg_restore_relation_stats(
    'relation', 'public.tenk1_pkey'::regclass,
    'version', '180000'::integer,
    'relpages', '30'::integer,
    'reltuples', '10000'::real,
    'relallvisible', '0'::integer
);