Horton

Re: wal stats questions

Andres Freund <andres@anarazel.de>

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From: "Andres Freund" <andres@anarazel.de>
To: "Fujii Masao" <masao.fujii@oss.nttdata.com>, "Masahiro Ikeda" <ikedamsh@oss.nttdata.com>, torikoshia <torikoshia@oss.nttdata.com>
Cc: "PostgreSQL Development" <pgsql-hackers@postgresql.org>, "Kyotaro Horiguchi" <horikyota.ntt@gmail.com>
Date: 2021-04-22T15:36:59Z
Lists: pgsql-hackers 
Hi

On Thu, Apr 22, 2021, at 06:42, Fujii Masao wrote:
> 
> 
> On 2021/04/21 18:31, Masahiro Ikeda wrote:
> >> BTW, is it better to change PgStat_Counter from int64 to uint64 because> there aren't any counters with negative number?
> 
> On second thought, it's ok even if the counters like wal_records get overflowed.
> Because they are always used to calculate the diff between the previous and
> current counters. Even when the current counters are overflowed and
> the previous ones are not, WalUsageAccumDiff() seems to return the right
> diff of them. If this understanding is right, I'd withdraw my comment and
> it's ok to use "long" type for those counters. Thought?

Why long? It's of a platform dependent size, which doesn't seem useful here?

Andres

Commits

  1. Fix issues in pg_stat_wal.

  2. Change data type of counters in BufferUsage and WalUsage from long to int64.