Re: buffer assertion tripping under repeat pgbench load

On 12/23/12 1:10 PM, Tom Lane wrote:

> It might also be interesting to know if there is more than one
> still-pinned buffer --- that is, if you're going to hack the code, fix
> it to elog(LOG) each pinned buffer and then panic after completing the
> loop.

Easy enough; I kept it so the actual source of panic is still an
assertion failure:

diff --git a/src/backend/storage/buffer/bufmgr.c
b/src/backend/storage/buffer/bufmgr.c
index dddb6c0..df43643 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -1697,11 +1697,21 @@ AtEOXact_Buffers(bool isCommit)
if (assert_enabled)
{
int i;
+ int RefCountErrors = 0;

for (i = 0; i < NBuffers; i++)
{
- Assert(PrivateRefCount[i] == 0);
+
+ if (PrivateRefCount[i] != 0)
+ {
+ BufferDesc *bufHdr = &BufferDescriptors[i];
+ elog(LOG, "refcount of %s is %u should
be 0, globally: %u",
+ relpathbackend(bufHdr->tag.rnode,
InvalidBackendId, bufHdr->tag.forkNum),
+ PrivateRefCount[i], bufHdr->refcount);
+ RefCountErrors++;
+ }
}
+ Assert(RefCountErrors == 0);
}
#endif