Horton

Re: SLRU statistics

Tomas Vondra <tomas.vondra@2ndquadrant.com>

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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Kuntal Ghosh <kuntalghosh.2007@gmail.com>
Cc: "Shinoda, Noriyoshi (PN Japan A&PS Delivery)" <noriyoshi.shinoda@hpe.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, "tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2020-04-07T17:29:06Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix async.c to not register any SLRU stats counts in the postmaster.

  2. Use proper GetDatum function in pg_stat_get_slru().

  3. Initialize SLRU stats entries to zero.

  4. Remove pg_xact from pg_stat_reset_slru docs

  5. Remove pg_xact entry from SLRU stats

  6. Track SLRU page hits in SimpleLruReadPage_ReadOnly

  7. Fix typo in SLRU stats documentation

  8. Collect statistics about SLRU caches

  9. Simplify and rename some GUC variables, per various recent discussions:

On Tue, Apr 07, 2020 at 05:01:37PM +0530, Kuntal Ghosh wrote:
>Hello Tomas,
>
>On Thu, Apr 2, 2020 at 5:59 PM Tomas Vondra
><tomas.vondra@2ndquadrant.com> wrote:
>> Thank you for the patch, pushed.
>>
>In SimpleLruReadPage_ReadOnly, we first try to find the SLRU page in
>shared buffer under shared lock, then conditionally visit
>SimpleLruReadPage if reading is necessary. IMHO, we should update
>hit_count if we can find the buffer in SimpleLruReadPage_ReadOnly
>directly. Am I missing something?
>
>Attached a patch for the same.
>

Yes, I think that's correct - without this we fail to account for
(possibly) a quite significant number of hits. Thanks for the report,
I'll get this pushed later today.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
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