Re: [HACKERS] Microvacuum support for Hash Index

Hi Ashutosh,

On 01/10/2017 08:40 AM, Jesper Pedersen wrote:
> On 01/10/2017 05:24 AM, Ashutosh Sharma wrote:
>> Thanks for reporting this problem. It is basically coming because i
>> forgot to unpin the bucketbuf in hash_xlog_vacuum_one_page(). Please
>> find the attached v5 patch that fixes the issue.
>>
>
> The crash is now fixed, but the
>
> --- test.sql ---
> \set id random(1,10)
> \set val random(0,10)
> BEGIN;
> UPDATE test SET val = :val WHERE id = :id;
> COMMIT;
> --- test.sql ---
>
> case gives
>
> client 6 aborted in command 3 of script 0; ERROR:  deadlock detected
> DETAIL:  Process 14608 waits for ShareLock on transaction 1444620;
> blocked by process 14610.
> Process 14610 waits for ShareLock on transaction 1444616; blocked by
> process 14608.
> HINT:  See server log for query details.
> CONTEXT:  while rechecking updated tuple (12,3) in relation "test"
> ...
>
> using pgbench -M prepared -c 10 -j 10 -T 300 -f test.sql test
>

I'm not seeing this deadlock with just the WAL v8 patch applied.

Best regards, Jesper