On 2025/05/31 15:26, Daniil Davydov wrote:
Hi,
On Sat, May 31, 2025 at 7:49 AM Michael Paquier <mich...@paquier.xyz> wrote:
On Fri, May 30, 2025 at 06:01:16PM +0700, Daniil Davydov wrote:
For now we fully scan local buffers for each fork of the temporary
relation that we want to truncate (in order to drop its buffers). It
happens in the function "DropRelationBuffers".
There used to be the same problem for regular tables (i.e. shared
buffers) and it was fixed in commit [1] and now shared buffers are
scanned only one time for those three relation forks.
I suggest making the same fix for temporary relations. See attached patch.
Applying the same kind of optimization for local buffers makes sense
here, even if the impact is more limited than regular relations.
+1
Please make sure to add this patch to the next commit fest.
OK, already created.
Here are a few review comments on the patch:
+ for (j = 0; j < nforks; j++)
{
- InvalidateLocalBuffer(bufHdr, true);
+ if ((buf_state & BM_TAG_VALID) &&
+ BufTagGetForkNum(&bufHdr->tag) == forkNum[j] &&
+ bufHdr->tag.blockNum >= firstDelBlock[j])
+ {
+ InvalidateLocalBuffer(bufHdr, true);
+ }
It looks like the "buf_state & BM_TAG_VALID" check can be moved
outside the loop, along with the BufTagMatchesRelFileLocator() check.
That would avoid unnecessary looping.
Also, should we add a "break" right after calling InvalidateLocalBuffer()?
Since the buffer has already been invalidated, continuing the loop
may not be necessary.
Regards,
--
Fujii Masao
NTT DATA Japan Corporation
