Re: Parallel Seq Scan - Mailing list pgsql-hackers

From Kouhei Kaigai
Subject Re: Parallel Seq Scan
Date
Msg-id 9A28C8860F777E439AA12E8AEA7694F80112001E@BPXM15GP.gisp.nec.co.jp
Whole thread Raw
In response to Re: Parallel Seq Scan  (Haribabu Kommi <kommi.haribabu@gmail.com>)
Responses Re: Parallel Seq Scan
List pgsql-hackers
Hi Amit,

Could you tell me the code intention around ExecInitFunnel()?

ExecInitFunnel() calls InitFunnel() that opens the relation to be
scanned by the underlying PartialSeqScan and setup ss_ScanTupleSlot
of its scanstate.
According to the comment of InitFunnel(), it open the relation and
takes appropriate lock on it. However, an equivalent initialization
is also done on InitPartialScanRelation().

Why does it acquire the relation lock twice?

Thanks,
--
NEC Business Creation Division / PG-Strom Project
KaiGai Kohei <kaigai@ak.jp.nec.com>


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