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>, 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>, Tomas Vondra <tomas.vondra@enterprisedb.com>, alvherre@alvh.no-ip.org
Date: 2024-09-23T00:57:01Z
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 Tue, Sep 17, 2024 at 5:03 PM Corey Huinker <corey.huinker@gmail.com> wrote:
>>
>> 1. make sure these three functions: 'pg_set_relation_stats',
>> 'pg_restore_relation_stats','pg_clear_relation_stats' proisstrict to true.
>> because in
>> pg_class catalog, these three attributes (relpages, reltuples, relallvisible) is
>> marked as not null. updating it to null will violate these constraints.
>> tom also mention this at [
>
> Things have changed a bit since then, and the purpose of the functions has changed, so the considerations are now different. The function signature could change in the future as new pg_class stats are added, and it might not still be strict.
>

if you add more arguments to relation_statistics_update,
but the first 3 arguments (relpages, reltuples, relallvisible) still not null.
and, we are unlikely to add 3 or more (nullable=null) arguments?

we have code like:
    if (!PG_ARGISNULL(RELPAGES_ARG))
    {
            values[ncols] = Int32GetDatum(relpages);
            ncols++;
    }
    if (!PG_ARGISNULL(RELTUPLES_ARG))
    {
            replaces[ncols] = Anum_pg_class_reltuples;
            values[ncols] = Float4GetDatum(reltuples);
    }
    if (!PG_ARGISNULL(RELALLVISIBLE_ARG))
    {
           values[ncols] = Int32GetDatum(relallvisible);
            ncols++;
    }
    newtup = heap_modify_tuple_by_cols(ctup, tupdesc, ncols, replaces, nulls);

you just directly declared "bool nulls[3]    = {false, false, false};"
if any of (RELPAGES_ARG, RELTUPLES_ARG, RELALLVISIBLE_ARG)
is null, should you set that null[position] to true?
otherwise, i am confused with the variable nulls.

Looking at other usage of heap_modify_tuple_by_cols, "ncols" cannot be
dynamic, it should be a fixed value?
The current implementation works, because the (bool[3] nulls) is
always false, never changed.
if nulls becomes {false, false, true} then "ncols" must be 3, cannot be 2.




>>
>> 8. lock_check_privileges function issue.
>> ------------------------------------------------
>> --asume there is a superuser jian
>> create role alice NOSUPERUSER LOGIN;
>> create role bob NOSUPERUSER LOGIN;
>> create role carol NOSUPERUSER LOGIN;
>> alter database test owner to alice
>> GRANT CONNECT, CREATE on database test to bob;
>> \c test bob
>> create schema one;
>> create table one.t(a int);
>> create table one.t1(a int);
>> set session AUTHORIZATION; --switch to superuser.
>> alter table one.t1 owner to carol;
>> \c test alice
>> --now current database owner alice cannot do ANYTHING WITH table one.t1,
>> like ANALYZE, SELECT, INSERT, MAINTAIN etc.
>
>
> Interesting.
>

database owners do not necessarily have schema USAGE privilege.
-------------<<<>>>------------------
create role alice NOSUPERUSER LOGIN;
create role bob NOSUPERUSER LOGIN;
create database test;
alter database test owner to alice;
GRANT CONNECT, CREATE on database test to bob;
\c test bob
create schema one;
create table one.t(a int);
\c test alice

analyze one.t;

with cte as (
select oid as the_t
from pg_class
where relname = any('{t}') and relnamespace = 'one'::regnamespace)
SELECT
pg_catalog.pg_set_relation_stats(
relation => the_t,
relpages => 17::integer,
reltuples => 400.0::real,
relallvisible => 4::integer)
from cte;


In the above case, alice cannot do "analyze one.t;",
but can do pg_set_relation_stats, which seems not ok?
-------------<<<>>>------------------

src/include/statistics/stats_utils.h
comment
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/statistics/statistics.h

should be "src/include/statistics/stats_utils.h"



comment src/backend/statistics/stats_utils.c
 * IDENTIFICATION
 *       src/backend/statistics/stats_privs.c
should be
 * IDENTIFICATION
 *       src/backend/statistics/stats_utils.c