Horton

Re: [HACKERS] [postgresql 10 beta3] unrecognized node type: 90

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Noah Misch <noah@leadboat.com>, "Adam, Etienne (Nokia-TECH/Issy Les Moulineaux)" <etienne.adam@nokia.com>, PostgreSQL Bugs <pgsql-bugs@postgresql.org>, "Duquesne, Pierre (Nokia-TECH/Issy Les Moulineaux)" <pierre.duquesne@nokia.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-08-28T14:47:58Z
Lists: pgsql-bugs, pgsql-hackers 
Amit Kapila <amit.kapila16@gmail.com> writes:
> On Mon, Aug 28, 2017 at 6:34 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> If what you're complaining about is that I put back the "if
>> (outerPlan->chgParam == NULL)" test to allow postponement of the
>> recursive ExecReScan call, I'm afraid that it's mere wishful
>> thinking that omitting that test in nodeGather did anything.

> Previously outerPlan->chgParam will be NULL, so I think rescan's won't
> be postponed.

That seems like an unacceptably fragile assumption.  Even if it happens to
be true today, we would need to fix it sooner or later.  (And I kinda
suspect it's possible to break it today, anyway.  Treating PARAM_EXEC
Params as parallel-restricted seems to lock out the easiest cases, but we
have param slots that don't correspond to any Param node, eg for recursive
union worktables.  replace_nestloop_params is also a source of PARAM_EXEC
Params that won't be detected during is_parallel_safe() tests, because it
happens later.)

			regards, tom lane

Commits

  1. Separate reinitialization of shared parallel-scan state from ExecReScan.

  2. Restore test case from a2b70c89ca1a5fcf6181d3c777d82e7b83d2de1b.

  3. Force rescanning of parallel-aware scan nodes below a Gather[Merge].

  4. Fix ExecReScanGatherMerge.

  5. Add missing call to ExecReScanGatherMerge.