Details
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Bug
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Status: Open (View Workflow)
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Major
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Resolution: Unresolved
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10.11, 11.4, 11.8, 12.3, 13.0, 13.1, 13.2
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None
Description
--source include/have_partition.inc
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CREATE TABLE t1 (c TINYINT) PARTITION BY LIST (c) (PARTITION p0 VALUES IN (1,2), PARTITION pdef DEFAULT); |
INSERT INTO t1 VALUES (1),(3),(4); |
--let $n= query_get_value(SELECT COUNT(*) AS n FROM t1 WHERE c BETWEEN 1 AND 4, n, 1)
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if ($n != 3) |
{
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--die A range on a nullable TINYINT column misses the rows in the DEFAULT partition: the DEFAULT partition is pruned |
}
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DROP TABLE t1; |
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CREATE TABLE t1 (c SMALLINT) PARTITION BY LIST (c) (PARTITION p0 VALUES IN (1,2), PARTITION pdef DEFAULT); |
INSERT INTO t1 VALUES (1),(3),(257); |
--let $n= query_get_value(SELECT COUNT(*) AS n FROM t1 WHERE c BETWEEN 1 AND 257, n, 1)
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if ($n != 3) |
{
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--die A range on a nullable SMALLINT column with bounds 1 and 257 misses the rows in the DEFAULT partition |
}
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DROP TABLE t1; |
Leads to:
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CS 13.1.2 87e62ca17270e163a6d41b3fc8d6f4d440f1bb88 (Optimized, Clang 22.1.8-20260622) Build 06/10/2026 |
mysqltest: At line 8: A range on a nullable TINYINT column misses the rows in the DEFAULT partition: the DEFAULT partition is pruned
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Partitioning changes the query result. Without partitioning, or with a NOT NULL column, the count is 3. EXPLAIN PARTITIONS shows p0 only. A range whose two bounds differ only in the highest byte of the value is pruned like an equality. For a TINYINT column, that is every BETWEEN. For the SMALLINT table, BETWEEN 1 AND 257 misses the rows in pdef, BETWEEN 1 AND 258 finds them, and BETWEEN 2 AND 258 returns no row. A nullable YEAR column, also one byte, gives the same. InnoDB, Aria and debug builds give the same result.
From the code it seems that in get_part_iter_for_interval_via_mapping() (sql/sql_partition.cc), the memcmp(min_value, max_value, field_len) that sets can_match_multiple_values starts at the NULL indicator byte of a nullable field, so it does not compare the last byte of the value. With can_match_multiple_values false, ret_default_part is not set.
