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Commite5691cc

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Don't use_physical_tlist for an IOS with non-returnable columns.
createplan.c tries to save a runtime projection step by specifyinga scan plan node's output as being exactly the table's columns, orindex's columns in the case of an index-only scan, if there is not areason to do otherwise. This logic did not previously pay attentionto whether an index's columns are returnable. That worked, sort ofaccidentally, until commit9a3ddeb taught setrefs.c to reject plansthat try to read a non-returnable column. I have no desire to loosensetrefs.c's new check, so instead adjust use_physical_tlist() to nottry to optimize this way when there are non-returnable column(s).Per report from Ryan Kelly. Like the previous patch, back-patchto all supported branches.Discussion:https://postgr.es/m/CAHUie24ddN+pDNw7fkhNrjrwAX=fXXfGZZEHhRuofV_N_ftaSg@mail.gmail.com
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‎src/backend/optimizer/plan/createplan.c

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Original file line numberDiff line numberDiff line change
@@ -914,6 +914,22 @@ use_physical_tlist(PlannerInfo *root, Path *path, int flags)
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return false;
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}
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/*
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* For an index-only scan, the "physical tlist" is the index's indextlist.
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* We can only return that without a projection if all the index's columns
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* are returnable.
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*/
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if (path->pathtype==T_IndexOnlyScan)
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{
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IndexOptInfo*indexinfo= ((IndexPath*)path)->indexinfo;
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for (i=0;i<indexinfo->ncolumns;i++)
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{
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if (!indexinfo->canreturn[i])
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return false;
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}
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}
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/*
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* Also, can't do it if CP_LABEL_TLIST is specified and path is requested
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* to emit any sort/group columns that are not simple Vars. (If they are

‎src/test/regress/expected/gist.out

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Original file line numberDiff line numberDiff line change
@@ -357,6 +357,22 @@ select p from gist_tbl where circle(p,1) @> circle(point(0,0),0.95);
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(0,0)
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(1 row)
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-- Also check that use_physical_tlist doesn't trigger in such cases.
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explain (verbose, costs off)
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select count(*) from gist_tbl;
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QUERY PLAN
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---------------------------------------------------------------------
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Aggregate
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Output: count(*)
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-> Index Only Scan using gist_tbl_multi_index on public.gist_tbl
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(3 rows)
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select count(*) from gist_tbl;
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count
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-------
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10001
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(1 row)
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-- This case isn't supported, but it should at least EXPLAIN correctly.
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explain (verbose, costs off)
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select p from gist_tbl order by circle(p,1) <-> point(0,0) limit 1;

‎src/test/regress/sql/gist.sql

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Original file line numberDiff line numberDiff line change
@@ -159,6 +159,11 @@ explain (verbose, costs off)
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select pfrom gist_tblwherecircle(p,1) @>circle(point(0,0),0.95);
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select pfrom gist_tblwherecircle(p,1) @>circle(point(0,0),0.95);
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-- Also check that use_physical_tlist doesn't trigger in such cases.
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explain (verbose, costs off)
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selectcount(*)from gist_tbl;
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selectcount(*)from gist_tbl;
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-- This case isn't supported, but it should at least EXPLAIN correctly.
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explain (verbose, costs off)
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select pfrom gist_tblorder bycircle(p,1)<->point(0,0)limit1;

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