pgsql: Predicate locking in GIN index

Predicate locking in GIN index

Predicate locks are used on per page basis only if fastupdate = off, in
opposite case predicate lock on pending list will effectively lock whole index,
to reduce locking overhead, just lock a relation. Entry and posting trees are
essentially B-tree, so locks are acquired on leaf pages only.

Author: Shubham Barai with some editorization by me and Dmitry Ivanov
Review by: Alexander Korotkov, Dmitry Ivanov, Fedor Sigaev
Discussion: https://www.postgresql.org/message-id/flat/CALxAEPt5sWW+EwTaKUGFL5_XFcZ0MuGBcyJ70oqbWqr42YKR8Q(at)mail(dot)gmail(dot)com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/43d1ed60fdd96027f044e152176c0d45cd6bf443

Modified Files
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src/backend/access/gin/ginbtree.c | 22 +
src/backend/access/gin/gindatapage.c | 10 +-
src/backend/access/gin/ginget.c | 76 ++-
src/backend/access/gin/gininsert.c | 38 +-
src/backend/access/gin/ginutil.c | 10 +-
src/backend/access/gin/ginvacuum.c | 12 +-
src/backend/storage/lmgr/README-SSI | 9 +
src/include/access/gin_private.h | 4 +-
src/test/isolation/expected/predicate-gin.out | 756 ++++++++++++++++++++++++++
src/test/isolation/isolation_schedule | 1 +
src/test/isolation/specs/predicate-gin.spec | 134 +++++
11 files changed, 1054 insertions(+), 18 deletions(-)