Horton

Re: Extended Statistics set/restore/clear functions.

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: Tomas Vondra <tomas@vondra.me>, pgsql-hackers@lists.postgresql.org
Date: 2025-01-28T16:24:59Z
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. Add test doing some cloning of extended statistics data

  2. Add test for pg_restore_extended_stats() with multiranges

  3. Add support for "mcv" in pg_restore_extended_stats()

  4. Include extended statistics data in pg_dump

  5. Add support for "dependencies" in pg_restore_extended_stats()

  6. Add test for MAINTAIN permission with pg_restore_extended_stats()

  7. Add pg_restore_extended_stats()

  8. Add routine to free MCVList

  9. Improve pg_clear_extended_stats() with incorrect relation/stats combination

  10. Add pg_clear_extended_stats()

  11. Introduce routines to validate and free MVNDistinct and MVDependencies

  12. Fix typo in stat_utils.c

  13. Move attribute statistics functions to stat_utils.c

  14. Improve error messages of input functions for pg_dependencies and pg_ndistinct

  15. Improve test output of extended statistics for ndistinct and dependencies

  16. Fix some compiler warnings

  17. Add input function for data type pg_dependencies

  18. Add input function for data type pg_ndistinct

  19. Rework output format of pg_dependencies

  20. Rework output format of pg_ndistinct

  21. Fix comments of output routines for pg_ndistinct and pg_dependencies

  22. Move code specific to pg_dependencies to new file

  23. Move code specific to pg_ndistinct to new file

  24. Document some structures in attribute_stats.c

  25. Fix FATAL message for invalid recovery timeline at beginning of recovery

hi.
I reviewed 0001 only.

in src/backend/statistics/mvdistinct.c

no need #include "nodes/pg_list.h" since
src/include/statistics/statistics.h sub level include "nodes/pg_list.h"

no need #include "utils/palloc.h"
sicne #include "postgres.h"
already included it.


 select '[{"6, -32768,,": -11}]'::pg_ndistinct;
ERROR:  malformed pg_ndistinct: "[{"6, -32768,,": -11}]"
LINE 1: select '[{"6, -32768,,": -11}]'::pg_ndistinct;
               ^
DETAIL:  All ndistinct count values are scalar doubles.
imho, this errdetail message is not good.


select '{}'::pg_ndistinct ;
segfault


select '{"1,":"1"}'::pg_ndistinct ;
ERROR:  malformed pg_ndistinct: "{"1,":"1"}"
LINE 1: select '{"1,":"1"}'::pg_ndistinct ;
               ^
DETAIL:  All ndistinct attnum lists must be a comma separated list of attnums.

imho, this errdetail message is not good. would be better saying that
"length of list of attnums must be larger than 1".



select  pt1.typnamespace, pt1.typarray, pt1.typcategory, pt1.typname
from    pg_type pt1
where pt1.typname ~*'distinct';

 typnamespace | typarray | typcategory |   typname
--------------+----------+-------------+--------------
           11 |        0 | Z           | pg_ndistinct

typcategory (Z) marked as Internal-use types. and there is no
pg_ndistinct array type,
not sure this is fine.


all the errcode one pair of the parenthesis is unnecessary.
for example
                (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                 errmsg("malformed pg_ndistinct: \"%s\"", parse->str),
                 errdetail("Must begin with \"{\"")));
can change to
                errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                 errmsg("malformed pg_ndistinct: \"%s\"", parse->str),
                 errdetail("Must begin with \"{\""));

see https://www.postgresql.org/docs/current/error-message-reporting.html