Horton

Re: Tid scan improvements

Zhihong Yu <zyu@yugabyte.com>

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From: Zhihong Yu <zyu@yugabyte.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Edmund Horner <ejrh00@gmail.com>, David Fetter <david@fetter.org>, Michael Paquier <michael@paquier.xyz>, Alvaro Herrera <alvherre@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@gmail.com>, David Steele <david@pgmasters.net>, Tom Lane <tgl@sss.pgh.pa.us>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2021-01-26T02:50:02Z
Lists: pgsql-hackers 
Hi,

bq. within this range.  Table AMs where scanning ranges of TIDs does not
make
sense or is difficult to implement efficiently may choose to not implement

Is there criterion on how to judge efficiency ?

+       if (tidopexpr->exprtype == TIDEXPR_LOWER_BOUND)
...
+       if (tidopexpr->exprtype == TIDEXPR_UPPER_BOUND)

The if statement for upper bound should be prefixed with 'else', right ?

+ * TidRecheck -- access method routine to recheck a tuple in EvalPlanQual
...
+TidRangeRecheck(TidRangeScanState *node, TupleTableSlot *slot)

The method name in the comment doesn't match the real method name.

+ *     ExecTidRangeScan(node)
...
+ExecTidRangeScan(PlanState *pstate)

Parameter names don't match.

Cheers

On Mon, Jan 25, 2021 at 5:23 PM David Rowley <dgrowleyml@gmail.com> wrote:

> On Thu, 21 Jan 2021 at 18:16, David Rowley <dgrowleyml@gmail.com> wrote:
> > I've implemented this in the attached.
>
> The bug fix in 0001 is now committed, so I'm just attaching the 0002
> patch again after having rebased... This is mostly just to keep the
> CFbot happy.
>
> David
>

Commits

  1. Add TID Range Scans to support efficient scanning ranges of TIDs

  2. Improve planner's selectivity estimates for inequalities on CTID.