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MDEV-25380: JSON_TABLE: Assertion `join->best_read < double(1.797...) fails

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The query used a subquery of this form:

SELECT ...
WHERE
   EXISTS( SELECT ...
           FROM JSON_TABLE(outer_ref, ..) as JT
           WHERE trivial_correlation_cond)

EXISTS-to-IN conversion code was unable to see that the subquery will
still be correlated after the trivial_correlation is removed, which
eventually caused a crash due to inability to construct a query plan.

Fixed by making Item_subselect::walk() also walk arguments of Table
Functions.
This commit is contained in:
Sergei Petrunia
2021-04-12 14:11:37 +03:00
committed by Alexey Botchkov
parent eb2550ee78
commit 4a10dd0253
5 changed files with 75 additions and 0 deletions
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16
mysql-test/suite/json/r/json_table.result
View File

@@ -734,5 +734,21 @@ Shirt blue 20
Shirt white 20
drop table t1;
#
# MDEV-25380: JSON_TABLE: Assertion `join->best_read < double(1.797...) fails
#
CREATE TABLE t1 (a INT, b TEXT);
INSERT INTO t1 VALUES (1,'{}'),(2,'[]');
explain
SELECT *
FROM t1
WHERE
EXISTS(SELECT *
FROM JSON_TABLE(b, '$' COLUMNS(o FOR ORDINALITY)) AS jt
WHERE jt.o = t1.a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
1 PRIMARY jt ALL NULL NULL NULL NULL 40 Table function: json_table; Using where; FirstMatch(t1)
drop table t1;
#
# End of 10.6 tests
#