On Wed, May 26, 2021 at 05:23:55PM -0400, Greg Sabino Mullane wrote: > The attached patch makes an optimization to pg_checksums which prevents > rewriting the block if the checksum is already what we expect. This can > lead to much faster runs in cases where it is already set (e.g. enabled -> > disabled -> enable, external helper process, interrupted runs, future > parallel processes).
Makes sense.
> There is also an effort to not sync the data directory
> if no changes were written. Finally, added a bit more output on how many
> files were actually changed, e.g.:
- if (do_sync)
+ if (do_sync && total_files_modified)
{
pg_log_info("syncing data directory");
fsync_pgdata(DataDir, PG_VERSION_NUM);
Here, I am on the edge. It could be an advantage to force a flush of
the data folder anyway, no? Say, all the pages have a correct
checksum and they are in the OS cache, but they may not have been
flushed yet. That would emulate what initdb -S does already.
> Checksum operation completed
> Files scanned: 1236
> Blocks scanned: 23283
> Files modified: 38
> Blocks modified: 19194
> pg_checksums: syncing data directory
> pg_checksums: updating control file
> Checksums enabled in cluster
The addition of the number of files modified looks like an advantage.
--
Michael
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