Hello tender wang,
26.12.2023 19:55, tender wang write:
I tried to analyze the issue, and I found that it might be caused by this commit:
commit dad50f677c42de207168a3f08982ba23c9fc6720
bufmgr: Acquire and clean victim buffer separately
Thanks for looking into it!
...
With debug logging added in this code within ExtendBufferedRelLocal():
if (found)
{
BufferDesc *existing_hdr =
GetLocalBufferDescriptor(hresult->id);
uint32 buf_state;
UnpinLocalBuffer(BufferDescriptorGetBuffer(victim_buf_hdr));
existing_hdr = GetLocalBufferDescriptor(hresult->id);
PinLocalBuffer(existing_hdr, false);
buffers[i] = BufferDescriptorGetBuffer(existing_hdr);
buf_state = pg_atomic_read_u32(&existing_hdr->state);
Assert(buf_state & BM_TAG_VALID);
Assert(!(buf_state & BM_DIRTY));
buf_state &= BM_VALID;
pg_atomic_unlocked_write_u32(&existing_hdr->state, buf_state);
...
I see that it reached for the second INSERT (and NOSPC error) with
existing_hdr->state == 0x2040000, but for the third INSERT I observe
state == 0x0.
I wonder, if "buf_state &= BM_VALID" is a typo here, maybe it supposed to be
"buf_state &= ~BM_VALID" as in ExtendBufferedRelShared()...
Best regards,
Alexander
