Re: Broken stuff in new dtrace probes

From: Robert Lor <Robert(dot)Lor(at)Sun(dot)COM>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Greg Stark <stark(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Broken stuff in new dtrace probes
Date: 2009-03-24 21:40:53
Message-ID: 49C95365.6030000@sun.com
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Tom Lane wrote:
> Greg Stark <stark(at)enterprisedb(dot)com> writes:
>
>> i like the idea of just have a separate pair of probes for table
>> extension. I bet there are people who would actually like to see that
>> alone sometimes too.
>>
>
> After further thought I concluded that the best solution for this is to
> add the isExtend flag to the buffer_read_start/read_done probe parameter
> lists. This allows the dtrace script writer to make the distinction if
> he chooses, without adding any extra overhead for normal non-traced
> operation. AFAICS using a separate probe type would add at least a
> couple of if-tests even with tracing turned off.
>
I like this solution. From my perspective, it's always better to give
the script writer the flexibility to pick and choose the data s/she
wants to see and at the same time avoid adding new probes unnecessarily.

-Robert

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