pgsql: Rework the pg_statistic_ext catalog - Mailing list pgsql-committers
From | Tomas Vondra |
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Subject | pgsql: Rework the pg_statistic_ext catalog |
Date | |
Msg-id | E1hcHz2-0005mY-5A@gemulon.postgresql.org Whole thread Raw |
Responses |
Re: pgsql: Rework the pg_statistic_ext catalog
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List | pgsql-committers |
Rework the pg_statistic_ext catalog Since extended statistic got introduced in PostgreSQL 10, there was a single catalog pg_statistic_ext storing both the definitions and built statistic. That's however problematic when a user is supposed to have access only to the definitions, but not to user data. Consider for example pg_dump on a database with RLS enabled - if the pg_statistic_ext catalog respects RLS (which it should, if it contains user data), pg_dump would not see any records and the result would not define any extended statistics. That would be a surprising behavior. Until now this was not a pressing issue, because the existing types of extended statistic (functional dependencies and ndistinct coefficients) do not include any user data directly. This changed with introduction of MCV lists, which do include most common combinations of values. The easiest way to fix this is to split the pg_statistic_ext catalog into two - one for definitions, one for the built statistic values. The new catalog is called pg_statistic_ext_data, and we're maintaining a 1:1 relationship with the old catalog - either there are matching records in both catalogs, or neither of them. Bumped CATVERSION due to changing system catalog definitions. Author: Dean Rasheed, with improvements by me Reviewed-by: Dean Rasheed, John Naylor Discussion: https://postgr.es/m/CAEZATCUhT9rt7Ui%3DVdx4N%3D%3DVV5XOK5dsXfnGgVOz_JhAicB%3DZA%40mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/6cbfb784c3c91146148a76d50cda6f69ae6a79fb Modified Files -------------- doc/src/sgml/catalogs.sgml | 70 ++++++++++++++++++++++----- doc/src/sgml/func.sgml | 6 +-- doc/src/sgml/perform.sgml | 20 ++++---- doc/src/sgml/planstats.sgml | 4 +- src/backend/catalog/Makefile | 2 +- src/backend/commands/statscmds.c | 73 ++++++++++++++++++++++------- src/backend/optimizer/util/plancat.c | 12 +++-- src/backend/statistics/README.mcv | 9 ++-- src/backend/statistics/dependencies.c | 7 +-- src/backend/statistics/extended_stats.c | 61 +++++++++++++----------- src/backend/statistics/mcv.c | 7 +-- src/backend/statistics/mvdistinct.c | 7 +-- src/backend/utils/cache/syscache.c | 12 +++++ src/include/catalog/catversion.h | 2 +- src/include/catalog/indexing.h | 17 ++++--- src/include/catalog/pg_statistic_ext.h | 9 ++-- src/include/catalog/pg_statistic_ext_data.h | 52 ++++++++++++++++++++ src/include/catalog/toasting.h | 1 + src/include/utils/syscache.h | 1 + src/test/regress/expected/oidjoins.out | 8 ++++ src/test/regress/expected/sanity_check.out | 1 + src/test/regress/expected/stats_ext.out | 38 ++++++++++----- src/test/regress/sql/oidjoins.sql | 4 ++ src/test/regress/sql/stats_ext.sql | 30 ++++++++---- src/tools/pgindent/typedefs.list | 2 + 25 files changed, 337 insertions(+), 118 deletions(-)
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