Date: Fri, 11 May 2007 15:39:50 +0200
From: Zdenek Kotala <Zdenek.Kotala@Sun.COM>
Subject: Re: race condition in pgplsql call handler?
In-reply-to: <17475.1178888659@sss.pgh.pa.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
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Tom Lane wrote:
> Zdenek Kotala <Zdenek.Kotala@Sun.COM> writes:
>> I'm looking into PG/PLSql code and following code in 
>> plpgsql_call_handler looks strange:
> 
>>          /* Find or compile the function */
>>          func = plpgsql_compile(fcinfo, false);
> 
>>          /* Mark the function as busy, so it can't be deleted from under 
>> us */
>>          func->use_count++;
> 
> 
>> I don't have deep knowledge about this part of code. But what happen if 
>> in parallel execution "func" will be deleted between these two lines?
> 
> This is not a race condition because the backend is single-threaded.

I see. Each backend has own function cache and use_count is for handle 
recursion usage. Are my assumption correct?

		thanks Zdenek