Re: Race conditions, race conditions!

Patch applied. Thanks.

---------------------------------------------------------------------------

Qingqing Zhou wrote:
>
> "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes
> >
> > WARNING: relation "t1" page 196 is uninitialized --- fixing
> > TRAP: FailedAssertion("!((((PageHeader) ((PageHeader)
> pageHeader))->pd_upper == 0))", File: "hio.c", Line: 263)
> > LOG: server process (PID 11296) was terminated by signal 6
> >
>
> Inspired by this, can we put an asseration here:
>
> ---
> /*
> * lookup the buffer. IO_IN_PROGRESS is set if the requested
> * block is not currently in memory.
> */
> bufHdr = BufferAlloc(reln, blockNum, &found);
>
> + /* we are guaranted that nobody else has touched this will-be-new block */
> + Assert(!(found && isExtend));
>
> if (found)
> BufferHitCount++;
> ---
>
> BufferAlloc() consists of two parts, one is looking for the blockNum, the
> other is allocating a free buffer. If the asseration is good, then for
> "isExtend", we just need the second part. This could bring marginal
> performance benefits.
>
>
> Regards,
> Qingqing
>
>
>
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