| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Greg Stark <gsstark(at)mit(dot)edu> |
| Cc: | Martijn van Oosterhout <kleptog(at)svana(dot)org>, Simon Riggs <simon(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: That EXPLAIN ANALYZE patch still needs work |
| Date: | 2006-06-07 17:52:12 |
| Message-ID: | 10440.1149702732@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Greg Stark <gsstark(at)mit(dot)edu> writes:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
>> Nope, that is certainly not the explanation, because the hash table is
>> loaded in the (single) call of the Hash node at the start of the query.
>> It is static all through the sampled-and-not executions of the Hash Join
>> node, which is where our problem is.
> At the risk of asking a stupid question, it's not perchance including that
> hash build in the first sample it takes of the hash join node?
Sure. Which is one of the reasons why the first tuple is excluded from
the extrapolation...
regards, tom lane
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