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If an index has both returnable and non-returnable columns, and one of the non-returnable columns is an expression using a Var that is in a returnable column, then a query returning that expression could result in an index-only scan plan that attempts to read the non-returnable column, instead of recomputing the expression from the returnable column as intended. To fix, redefine the "indextlist" list of an IndexOnlyScan plan node as containing null Consts in place of any non-returnable columns. This solves the problem by preventing setrefs.c from falsely matching to such entries. The executor is happy since it only cares about the exposed types of the entries, and ruleutils.c doesn't care because a correct plan won't reference those entries. I considered some other ways to prevent setrefs.c from doing the wrong thing, but this way seems good since (a) it allows a very localized fix, (b) it makes the indextlist structure more compact in many cases, and (c) the indextlist is now a more faithful representation of what the index AM will actually produce, viz. nulls for any non-returnable columns. This is easier to hit since we introduced included columns, but it's possible to construct failing examples without that, as per the added regression test. Hence, back-patch to all supported branches. Per bug #17350 from Louis Jachiet. Discussion: https://postgr.es/m/17350-b5bdcf476e5badbb@postgresql.org
162 lines
5.3 KiB
SQL
162 lines
5.3 KiB
SQL
--
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-- Test GiST indexes.
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--
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-- There are other tests to test different GiST opclasses. This is for
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-- testing GiST code itself. Vacuuming in particular.
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create table gist_point_tbl(id int4, p point);
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create index gist_pointidx on gist_point_tbl using gist(p);
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-- Verify the fillfactor and buffering options
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create index gist_pointidx2 on gist_point_tbl using gist(p) with (buffering = on, fillfactor=50);
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create index gist_pointidx3 on gist_point_tbl using gist(p) with (buffering = off);
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create index gist_pointidx4 on gist_point_tbl using gist(p) with (buffering = auto);
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drop index gist_pointidx2, gist_pointidx3, gist_pointidx4;
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-- Make sure bad values are refused
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create index gist_pointidx5 on gist_point_tbl using gist(p) with (buffering = invalid_value);
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create index gist_pointidx5 on gist_point_tbl using gist(p) with (fillfactor=9);
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create index gist_pointidx5 on gist_point_tbl using gist(p) with (fillfactor=101);
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-- Insert enough data to create a tree that's a couple of levels deep.
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insert into gist_point_tbl (id, p)
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select g, point(g*10, g*10) from generate_series(1, 10000) g;
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insert into gist_point_tbl (id, p)
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select g+100000, point(g*10+1, g*10+1) from generate_series(1, 10000) g;
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-- To test vacuum, delete some entries from all over the index.
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delete from gist_point_tbl where id % 2 = 1;
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-- And also delete some concentration of values.
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delete from gist_point_tbl where id > 5000;
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vacuum analyze gist_point_tbl;
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-- rebuild the index with a different fillfactor
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alter index gist_pointidx SET (fillfactor = 40);
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reindex index gist_pointidx;
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--
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-- Test Index-only plans on GiST indexes
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--
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create table gist_tbl (b box, p point, c circle);
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insert into gist_tbl
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select box(point(0.05*i, 0.05*i), point(0.05*i, 0.05*i)),
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point(0.05*i, 0.05*i),
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circle(point(0.05*i, 0.05*i), 1.0)
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from generate_series(0,10000) as i;
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vacuum analyze gist_tbl;
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set enable_seqscan=off;
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set enable_bitmapscan=off;
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set enable_indexonlyscan=on;
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-- Test index-only scan with point opclass
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create index gist_tbl_point_index on gist_tbl using gist (p);
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-- check that the planner chooses an index-only scan
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explain (costs off)
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select p from gist_tbl where p <@ box(point(0,0), point(0.5, 0.5));
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-- execute the same
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select p from gist_tbl where p <@ box(point(0,0), point(0.5, 0.5));
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-- Also test an index-only knn-search
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explain (costs off)
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select p from gist_tbl where p <@ box(point(0,0), point(0.5, 0.5))
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order by p <-> point(0.201, 0.201);
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select p from gist_tbl where p <@ box(point(0,0), point(0.5, 0.5))
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order by p <-> point(0.201, 0.201);
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-- Check commuted case as well
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explain (costs off)
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select p from gist_tbl where p <@ box(point(0,0), point(0.5, 0.5))
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order by point(0.101, 0.101) <-> p;
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select p from gist_tbl where p <@ box(point(0,0), point(0.5, 0.5))
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order by point(0.101, 0.101) <-> p;
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-- Check case with multiple rescans (bug #14641)
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explain (costs off)
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select p from
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(values (box(point(0,0), point(0.5,0.5))),
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(box(point(0.5,0.5), point(0.75,0.75))),
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(box(point(0.8,0.8), point(1.0,1.0)))) as v(bb)
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cross join lateral
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(select p from gist_tbl where p <@ bb order by p <-> bb[0] limit 2) ss;
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select p from
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(values (box(point(0,0), point(0.5,0.5))),
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(box(point(0.5,0.5), point(0.75,0.75))),
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(box(point(0.8,0.8), point(1.0,1.0)))) as v(bb)
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cross join lateral
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(select p from gist_tbl where p <@ bb order by p <-> bb[0] limit 2) ss;
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drop index gist_tbl_point_index;
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-- Test index-only scan with box opclass
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create index gist_tbl_box_index on gist_tbl using gist (b);
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-- check that the planner chooses an index-only scan
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explain (costs off)
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select b from gist_tbl where b <@ box(point(5,5), point(6,6));
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-- execute the same
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select b from gist_tbl where b <@ box(point(5,5), point(6,6));
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-- Also test an index-only knn-search
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explain (costs off)
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select b from gist_tbl where b <@ box(point(5,5), point(6,6))
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order by b <-> point(5.2, 5.91);
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select b from gist_tbl where b <@ box(point(5,5), point(6,6))
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order by b <-> point(5.2, 5.91);
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-- Check commuted case as well
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explain (costs off)
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select b from gist_tbl where b <@ box(point(5,5), point(6,6))
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order by point(5.2, 5.91) <-> b;
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select b from gist_tbl where b <@ box(point(5,5), point(6,6))
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order by point(5.2, 5.91) <-> b;
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drop index gist_tbl_box_index;
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-- Test that an index-only scan is not chosen, when the query involves the
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-- circle column (the circle opclass does not support index-only scans).
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create index gist_tbl_multi_index on gist_tbl using gist (p, c);
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explain (costs off)
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select p, c from gist_tbl
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where p <@ box(point(5,5), point(6, 6));
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-- execute the same
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select b, p from gist_tbl
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where b <@ box(point(4.5, 4.5), point(5.5, 5.5))
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and p <@ box(point(5,5), point(6, 6));
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drop index gist_tbl_multi_index;
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-- Test that we don't try to return the value of a non-returnable
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-- column in an index-only scan. (This isn't GIST-specific, but
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-- it only applies to index AMs that can return some columns and not
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-- others, so GIST with appropriate opclasses is a convenient test case.)
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create index gist_tbl_multi_index on gist_tbl using gist (circle(p,1), p);
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explain (verbose, costs off)
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select circle(p,1) from gist_tbl
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where p <@ box(point(5, 5), point(5.3, 5.3));
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select circle(p,1) from gist_tbl
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where p <@ box(point(5, 5), point(5.3, 5.3));
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-- Clean up
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reset enable_seqscan;
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reset enable_bitmapscan;
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reset enable_indexonlyscan;
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drop table gist_tbl;
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