Horton

RE: [Proposal] Add accumulated statistics

Yotsunaga, Naoki <yotsunaga.naoki@jp.fujitsu.com>

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From: "Yotsunaga, Naoki" <yotsunaga.naoki@jp.fujitsu.com>
To: 'Robert Haas' <robertmhaas@gmail.com>
Cc: Bruce Momjian <bruce@momjian.us>, Phil Florent <philflorent@hotmail.com>, Michael Paquier <michael@paquier.xyz>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2019-01-11T00:30:47Z
Lists: pgsql-hackers 
On Thu, Jan 10, 2019 at 8:42 PM, Robert Hass wrote:

Thanks for comments.

>or at least not nearly as useful the results of a sampling approach.
I agree with your opinion.
Because it can't be asserted that the wait event is a bottleneck just because the number of wait event is large.
The same thing is mentioned in Oracle.
It also suggests that it is important to acquire waiting time for that.
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https://docs.oracle.com/en/database/oracle/oracle-database/18/tgdba/measuring-database-performance.html#GUID-811E9E65-C64A-4028-A90E-102BBFF6E68F
5.2.3 Using Wait Events without Timed Statistics
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>The data that LWLOCK_STATS produce are downright misleading 
Is that so？
I do not know the need for this function.

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Naoki Yotsunaga