Re: Why are we waiting? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Why are we waiting?
Date
Msg-id 9205.1202162782@sss.pgh.pa.us
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In response to Why are we waiting?  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: Why are we waiting?
List pgsql-hackers
Simon Riggs <simon@2ndquadrant.com> writes:
> I'm thinking of adding an extra parameter onto every call to
> LockBuffer() and LWLockAcquire() to explain the reason for the lock
> request.

Maybe I'm missing something, but I don't see what this would buy us,
except for being able to track which call site resulted in a wait;
which can already be measured with dtrace, no?

I'm hesitant to decorate such widely-used functions with extra tracing
information.  You'd be breaking every third-party module and pending
patch that uses either function, and imposing some performance penalty
(probably not much, but it's hard to be sure) into the indefinite
future, for a performance measurement need that might be fleeting.

Basically I'd rather try to attack the problem with dtrace ...
        regards, tom lane


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