Fix VACUUM's reporting of dead-tuple counts to the stats collector.
Historically, VACUUM has just reported its new_rel_tuples estimate
(the same thing it puts into pg_class.reltuples) to the stats collector.
That number counts both live and dead-but-not-yet-reclaimable tuples.
This behavior may once have been right, but modern versions of the
pgstats code track live and dead tuple counts separately, so putting
the total into n_live_tuples and zero into n_dead_tuples is surely
pretty bogus. Fix it to report live and dead tuple counts separately.
This doesn't really do much for situations where updating transactions
commit concurrently with a VACUUM scan (possibly causing double-counting or
omission of the tuples they add or delete); but it's clearly an improvement
over what we were doing before.
Hari Babu, reviewed by Amit Kapila
Branch
------
master
Details
-------
http://git.postgresql.org/pg/commitdiff/115f414124e71749d2d8f512e469ca63bc2166e5
Modified Files
--------------
src/backend/commands/vacuumlazy.c | 13 +++++++++++--
src/backend/postmaster/pgstat.c | 11 ++++++-----
src/include/pgstat.h | 5 +++--
3 files changed, 20 insertions(+), 9 deletions(-)