MDEV-29360 Crash when pushing condition with always false IS NULL int…#4788
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mariadb-RexJohnston wants to merge 1 commit into10.11from
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MDEV-29360 Crash when pushing condition with always false IS NULL int…#4788mariadb-RexJohnston wants to merge 1 commit into10.11from
mariadb-RexJohnston wants to merge 1 commit into10.11from
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…o derived When a condition containing an always FALSE range part is pushed down into a derived table, an enclosed outer reference can cause a null pointer crash. An example SELECT * FROM (SELECT id FROM t1 GROUP BY id) dt1, (SELECT id FROM t2) dt2, t3 WHERE dt2.id = t3.id AND dt1.id BETWEEN 0 AND (dt2.id IS NULL); is considered as one that can be pushed into the derived table dt1 because the expression (dt2.id IS NULL) is identified as always false. On the on other hand the condition still contains a reference to a column of the table dt2. When pushing the condition to the where clause of the derived table dt1 a copy of it is created and this copy is transformed to be used in the new where clause. When the transformation procedure encounters a reference dt2.id it crashes the server as only the references to the columns used in the group by list of the specification of dt1 or those equal to them are expected in the condition that can be pushed into the where clause of the derived table. Based on patch by Igor Babaev.
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…o derived
When a condition containing an always FALSE range part is pushed down into a derived table, an enclosed outer reference can cause a null pointer crash. An example
SELECT * FROM (SELECT id FROM t1 GROUP BY id) dt1, (SELECT id FROM t2) dt2, t3
WHERE dt2.id = t3.id AND dt1.id BETWEEN 0 AND (dt2.id IS NULL);
is considered as one that can be pushed into the derived table dt1 because the expression (dt2.id IS NULL) is identified as always false. On the on other hand the condition still contains a reference to a column of the table dt2. When pushing the condition to the where clause of the derived table dt1 a copy of it is created and this copy is transformed to be used in the new where clause. When the transformation procedure encounters a reference dt2.id it crashes the server as only the references to the columns used in the group by list of the specification of dt1 or those equal to them are expected in the condition that can be pushed into the where clause of the derived table.
Based on patch by Igor Babaev.