> > To understand the performance effects of the above, I have taken the > > average of five checkpoints with the patch and without the patch in my > > environment. Here are the results. > > With patch: 269.65 s > > Without patch: 269.60 s > > Those look like timed checkpoints - if the checkpoints are sleeping a > part of the time, you're not going to see any potential overhead.
Yes. The above data is collected from timed checkpoints. create table t1(a int); insert into t1 select * from generate_series(1,10000000); I generated a lot of data by using the above queries which would in turn trigger the checkpoint (wal). --- > To see whether this has an effect you'd have to make sure there's a > certain number of dirty buffers (e.g. by doing CREATE TABLE AS > some_query) and then do a manual checkpoint and time how long that > times. For this case I have generated data by using below queries. create table t1(a int); insert into t1 select * from generate_series(1,8000000); This does not trigger the checkpoint automatically. I have issued the CHECKPOINT manually and measured the performance by considering an average of 5 checkpoints. Here are the details. With patch: 2.457 s Without patch: 2.334 s Please share your thoughts. Thanks & Regards, Nitin Jadhav On Thu, Jul 7, 2022 at 5:34 AM Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2022-06-13 19:08:35 +0530, Nitin Jadhav wrote: > > > Have you measured the performance effects of this? On fast storage with > > > large > > > shared_buffers I've seen these loops in profiles. It's probably fine, but > > > it'd > > > be good to verify that. > > > > To understand the performance effects of the above, I have taken the > > average of five checkpoints with the patch and without the patch in my > > environment. Here are the results. > > With patch: 269.65 s > > Without patch: 269.60 s > > Those look like timed checkpoints - if the checkpoints are sleeping a > part of the time, you're not going to see any potential overhead. > > To see whether this has an effect you'd have to make sure there's a > certain number of dirty buffers (e.g. by doing CREATE TABLE AS > some_query) and then do a manual checkpoint and time how long that > times. > > Greetings, > > Andres Freund
