On 1/12/24 12:32 AM, Bharath Rupireddy wrote:
Test case:
./pgbench --initialize --scale=100 --username=ubuntu postgres
./pgbench --progress=10 --client=64 --time=300 --builtin=tpcb-like
--username=ubuntu postgres
Setup:
./configure --prefix=$PWD/inst/ CFLAGS="-ggdb3 -O3" > install.log &&
make -j 8 install > install.log 2>&1 &
shared_buffers = '8GB'
max_wal_size = '32GB'
track_wal_io_timing = on
Stats measured:
I've used the attached patch to measure WAL Insert Lock Acquire Time
(wal_insert_lock_acquire_time) and WAL Wait for In-progress Inserts
to Finish Time (wal_wait_for_insert_to_finish_time).
Unfortunately this leaves the question of how frequently is
WaitXLogInsertionsToFinish() being called and by whom. One possibility
here is that wal_buffers is too small so backends are constantly having
to write WAL data to free up buffers.
--
Jim Nasby, Data Architect, Austin TX
