Support disabling index bypassing by VACUUM.

Enterprise / PostgreSQL - Peter Geoghegan [] - 19 June 2021 03:04 UTC

Generalize the INDEX_CLEANUP VACUUM parameter (and the corresponding reloption): make it into a ternary style boolean parameter. It now exposes a third option, "auto". The "auto" option (which is now the default) enables the "bypass index vacuuming" optimization added by commit 1e55e7d1.

"VACUUM (INDEX_CLEANUP TRUE)" is redefined to once again make VACUUM simply do any required index vacuuming, regardless of how few dead tuples are encountered during the first scan of the target heap relation (unless there are exactly zero). This gives users a way of opting out of the "bypass index vacuuming" optimization, if for whatever reason that proves necessary. It is also expected to be used by PostgreSQL developers as a testing option from time to time.

"VACUUM (INDEX_CLEANUP FALSE)" does the same thing as it always has: it forcibly disables both index vacuuming and index cleanup. It's not expected to be used much in PostgreSQL 14. The failsafe mechanism added by commit 1e55e7d1 addresses the same problem in a simpler way. INDEX_CLEANUP can now be thought of as a testing and compatibility option.

Author: Peter Geoghegan

3499df0dee Support disabling index bypassing by VACUUM.
doc/src/sgml/ref/create_table.sgml | 23 +++++---
doc/src/sgml/ref/vacuum.sgml | 57 +++++++++++++-----
doc/src/sgml/ref/vacuumdb.sgml | 15 +++++
src/backend/access/common/reloptions.c | 35 ++++++++---
src/backend/access/heap/vacuumlazy.c | 105 ++++++++++++++++++++-------------
src/backend/commands/vacuum.c | 75 ++++++++++++++++-------
src/backend/postmaster/autovacuum.c | 10 +++-
src/bin/psql/tab-complete.c | 4 +-
src/bin/scripts/vacuumdb.c | 65 ++++++++++++++++----
src/include/commands/vacuum.h | 25 ++++----
src/include/utils/rel.h | 10 +++-
src/test/regress/expected/vacuum.out | 8 ++-
src/test/regress/sql/vacuum.sql | 8 ++-
13 files changed, 313 insertions(+), 127 deletions(-)


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