Thread: pgsql: Increase maximum number of clog buffers.

pgsql: Increase maximum number of clog buffers.

From
Andres Freund
Date:
Increase maximum number of clog buffers.

Benchmarking has shown that the current number of clog buffers limits
scalability. We've previously increased the number in 33aaa139, but
that's not sufficient with a large number of clients.

We've benchmarked the cost of increasing the limit by benchmarking worst
case scenarios; testing showed that 128 buffers don't cause a
regression, even in contrived scenarios, whereas 256 does

There are a number of more complex patches flying around to address
various clog scalability problems, but this is simple enough that we can
get it into 9.6; and is beneficial even after those patches have been
applied.

It is a bit unsatisfactory to increase this in small steps every few
releases, but a better solution seems to require a rewrite of slru.c;
not something done quickly.

Author: Amit Kapila and Andres Freund
Discussion: CAA4eK1+-=18HOrdqtLXqOMwZDbC_15WTyHiFruz7BvVArZPaAw@mail.gmail.com

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/5364b357fb115ed4dc7174085d8f59d9425638dd

Modified Files
--------------
src/backend/access/transam/clog.c | 29 +++++++++++------------------
1 file changed, 11 insertions(+), 18 deletions(-)