Thread

Re: Checkpointer write combining

Soumya S Murali <soumyamurali.work@gmail.com> — 2025-11-25T11:28:49Z

Hi all,
I applied the v11 patchset on my 19devel source code without any
modifications and ran some rounds of pgbench for testing. I ran
multiple workloads with different client counts and it executed
successfully without any backend crashes. I am including the
observations herewith for further review.

1. pgbench -c 4 -j 4 -T 10 -p 55432 postgres
pgbench (19devel)
starting vacuum...end.
transaction type: <builtin: TPC-B (sort of)>
scaling factor: 50
query mode: simple
number of clients: 4
number of threads: 4
maximum number of tries: 1
duration: 10 s
number of transactions actually processed: 10103
number of failed transactions: 0 (0.000%)
latency average = 3.958 ms
initial connection time = 4.970 ms
tps = 1010.552537 (without initial connection time)

2. pgbench -c 8 -j 8 -T 120 -p 55432 postgres
pgbench (19devel)
starting vacuum...end.
transaction type: <builtin: TPC-B (sort of)>
scaling factor: 50
query mode: simple
number of clients: 8
number of threads: 8
maximum number of tries: 1
duration: 120 s
number of transactions actually processed: 193468
number of failed transactions: 0 (0.000%)
latency average = 4.962 ms
initial connection time = 8.135 ms
tps = 1612.271773 (without initial connection time)

3. pgbench -c 16 -j 8 -T 180 -p 55432 postgres
pgbench (19devel)
starting vacuum...end.
transaction type: <builtin: TPC-B (sort of)>
scaling factor: 50
query mode: simple
number of clients: 16
number of threads: 8
maximum number of tries: 1
duration: 180 s
number of transactions actually processed: 598737
number of failed transactions: 0 (0.000%)
latency average = 4.810 ms
initial connection time = 13.793 ms
tps = 3326.398071 (without initial connection time)

I will continue testing with more workloads including forced
checkpoints to see if it can trigger any edge cases or WAL flush
decisions. But for now, the v11 series appears stable on my system.
Looking forward to more feedback.

Regards,
Soumya