From: Tom Lane <tgl@sss.pgh.pa.us>
To: Vladimir Ryabtsev <greatvovan@gmail.com>
Cc: ranade@nodalexchange.com
Cc: pgsql-performance@postgresql.org
Subject: Re: SELECT statement returns in 10seconds, but INSERT/CREATE TABLE AS with same SELECT takes 7 minutes
Date: Thu, 27 Sep 2018 16:41:29 -0400
Message-ID: <22616.1538080889@sss.pgh.pa.us> (raw)
In-Reply-To: <CAMqTPq=5KVOSKaxry0PFA8wVQWN8WsdycM=FSy1CUPUuGbDv7w@mail.gmail.com>
References: <CANrrCRxsC3wr711bjAJ4zK_16vF-qQHZXjSJTstbQt9kG5QDSw@mail.gmail.com>
<24273.1538068894@sss.pgh.pa.us>
<CAMqTPq=5KVOSKaxry0PFA8wVQWN8WsdycM=FSy1CUPUuGbDv7w@mail.gmail.com>
Vladimir Ryabtsev <greatvovan@gmail.com> writes:
>> The reason for the plan shape difference is probably that the bare SELECT
>> is allowed to use parallelism while INSERT/SELECT isn't.
> In case parallelism is used, should it report in the plan as something like
> "workers planned: N"?
It did --- see the Gather node.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, greatvovan@gmail.com, ranade@nodalexchange.com
Subject: Re: SELECT statement returns in 10seconds, but INSERT/CREATE TABLE AS with same SELECT takes 7 minutes
In-Reply-To: <22616.1538080889@sss.pgh.pa.us>
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