execution of nested loop joins

From: Esha Palta <esha(at)it(dot)iitb(dot)ac(dot)in>
To: pgsql-hackers(at)postgresql(dot)org
Subject: execution of nested loop joins
Date: 2005-10-06 15:44:02
Message-ID: 43454642.5070901@it.iitb.ac.in
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Hi all,

nodeNestloop.c executes nested loop joins. After getting a pair of inner
and outer it test the inner and outer tuples to see if they satisfy the
node's qualification using function ExecQual(joinqual, econtext, false).

ExecQual evaluates join conditions one at a time.It captures one
condition and passes it to function ExecEvalExpr which is actually a
macro that invokes another function evalfunc(a method of ExprState
structure).

I am not getting implementation and use of this evalfunc function. Is
this function used to evaluate the join condition or not. If yes, then
how it does this.

thanx
esha

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