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author | unknown <timour@askmonty.org> | 2010-10-26 14:55:42 +0300 |
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committer | unknown <timour@askmonty.org> | 2010-10-26 14:55:42 +0300 |
commit | b4d5f30a869857d532af0200fdb2204213c51f58 (patch) | |
tree | cddb89ae274394d3ce9fc8ea6685c3f493193f73 /sql/sql_expression_cache.h | |
parent | db4738a18a141955465b7a7e139fe25c832d6c44 (diff) | |
download | mariadb-git-b4d5f30a869857d532af0200fdb2204213c51f58.tar.gz |
Fixed LP bug #601156
The cause for this bug is that MariaDB 5.3 still processes derived tables
(subqueries in the FROM clause) by fully executing them during the parse
phase. This will be remedied by MWL#106 once merged into the main 5.3.
The assert statement is triggered when MATERIALIZATION is ON for EXPLAIN
EXTENDED for derived tables with an IN subquery as follows:
- mysql_parse calls JOIN::exec for the derived table as if it is regular
execution (not explain).
- When materialization is ON, this call goes all the way to
subselect_hash_sj_engine::exec, which creates a partial match engine
because of NULL presence.
- In order to proceed with normal execution, the hash_sj engine substitutes
itself with the created partial match engine.
- After the parse phase it turns out that this execution was part of
EXPLAIN EXTENDED, which in turn calls
Item_cond::print -> ... -> Item_subselect::print,
which calls engine->print().
Since subselect_hash_sj_engine::exec substituted the current
Item_subselect engine with a partial match engine, eventually we call
its ::print() method. However the partial match engines are designed only
for execution, hence there is no implementation of this print() method.
The fix temporarily removes the assert, until this code is merged with
MWL#106.
Diffstat (limited to 'sql/sql_expression_cache.h')
0 files changed, 0 insertions, 0 deletions