[COMMITTERS] pgsql: Avoid searching for callback functions inCallSyscacheCallbacks( - Mailing list pgsql-committers

From Tom Lane
Subject [COMMITTERS] pgsql: Avoid searching for callback functions inCallSyscacheCallbacks(
Date
Msg-id E1d9Jcy-0000aR-0A@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Avoid searching for callback functions in CallSyscacheCallbacks().

We have now grown enough registerable syscache-invalidation callback
functions that the original assumption that there would be few of them
is causing performance problems.  In particular, let's fix things so that
CallSyscacheCallbacks doesn't have to search the whole array to find
which callback(s) to invoke for a given cache ID.  Preserve the original
behavior that callbacks are called in order of registration, just in
case there's someplace that depends on that (which I doubt).

In support of this, export the number of syscaches from syscache.h.
People could have found that out anyway from the enum, but adding a
#define makes that much safer.

This provides a useful additional speedup in Mathieu Fenniak's
logical-decoding test case, although we're reaching the point of
diminishing returns there.  I think any further improvement will have
to come from reducing the number of cache invalidations that are
triggered in the first place.  Still, we can hope that this change
gives some incremental benefit for all invalidation scenarios.

Back-patch to 9.4 where logical decoding was introduced.

Discussion: https://postgr.es/m/CAHoiPjzea6N0zuCi=+f9v_j94nfsy6y8SU7-=bp4=7qw6_i=Rg@mail.gmail.com

Branch
------
REL9_5_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/e7955ac6481b5948a05b076222be50749f85bdb2

Modified Files
--------------
src/backend/utils/cache/inval.c    | 39 ++++++++++++++++++++++++++++++++++----
src/backend/utils/cache/syscache.c |  5 +++--
src/include/utils/syscache.h       |  2 ++
3 files changed, 40 insertions(+), 6 deletions(-)


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