Re: Patch: fix lock contention for HASHHDR.mutex - Mailing list pgsql-hackers

From Aleksander Alekseev
Subject Re: Patch: fix lock contention for HASHHDR.mutex
Date
Msg-id 20151211191441.3cc507b5@fujitsu
Whole thread Raw
In response to Re: Patch: fix lock contention for HASHHDR.mutex  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Patch: fix lock contention for HASHHDR.mutex  (Aleksander Alekseev <a.alekseev@postgrespro.ru>)
Re: Patch: fix lock contention for HASHHDR.mutex  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
Hello, Tom

I see your point, but I would like to clarify a few things.

1. Do we consider described measurement method good enough to conclude
that sometimes PostgreSQL really spends 3 ms in a spinlock (like a RTT
between two Internet hosts in the same city)? If not, what method
should be used to approve or disapprove this?

2. If we agree that PostgreSQL does sometimes spend 3 ms in a spinlock
do we consider this a problem?

3. If we consider this a problem, what method is considered appropriate
to find a real reason of such behaviour so we could fix it?

Best regards,
Aleksander



pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: [sqlsmith] Failed to generate plan on lateral subqueries
Next
From: Robert Haas
Date:
Subject: Re: Rework the way multixact truncations work