From 629557ff13e28e3422dfa1c354c44ef2fd62e4d0 Mon Sep 17 00:00:00 2001 From: Georgi Kodinov Date: Thu, 3 Sep 2009 18:03:46 +0300 Subject: [PATCH] Bug #46791: Assertion failed:(table->key_read==0),function unknown function,file sql_base.cc When uncacheable queries are written to a temp table the optimizer must preserve the original JOIN structure, because it is re-using the JOIN structure to read from the resulting temporary table. This was done only for uncacheable sub-queries. But top level queries can also benefit from this mechanism, specially if they're using index access and need a reset. Fixed by not limiting the saving of JOIN structure to subqueries exclusively. Added a new test file to extend the existing (large) subquery.test. --- mysql-test/r/subselect4.result | 30 ++++++++++++++++++++++++++++++ mysql-test/t/subselect4.test | 32 ++++++++++++++++++++++++++++++++ sql/sql_select.cc | 8 ++------ 3 files changed, 64 insertions(+), 6 deletions(-) create mode 100644 mysql-test/r/subselect4.result create mode 100644 mysql-test/t/subselect4.test diff --git a/mysql-test/r/subselect4.result b/mysql-test/r/subselect4.result new file mode 100644 index 00000000000..68577cb2a4c --- /dev/null +++ b/mysql-test/r/subselect4.result @@ -0,0 +1,30 @@ +# +# Bug #46791: Assertion failed:(table->key_read==0),function unknown +# function,file sql_base.cc +# +CREATE TABLE t1 (a INT, b INT, KEY(a)); +INSERT INTO t1 VALUES (1,1),(2,2); +CREATE TABLE t2 LIKE t1; +INSERT INTO t2 VALUES (1,1),(2,2); +CREATE TABLE t3 LIKE t1; +# should have 1 impossible where and 2 dependent subqueries +EXPLAIN +SELECT 1 FROM t1 +WHERE NOT EXISTS (SELECT 1 FROM t2 WHERE 1 = (SELECT MIN(t2.b) FROM t3)) +ORDER BY count(*); +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY t1 index NULL a 5 NULL 2 Using index; Using temporary +2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 2 Using where +3 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL no matching row in const table +# should not crash the next statement +SELECT 1 FROM t1 +WHERE NOT EXISTS (SELECT 1 FROM t2 WHERE 1 = (SELECT MIN(t2.b) FROM t3)) +ORDER BY count(*); +1 +1 +# should not crash: the crash is caused by the previous statement +SELECT 1; +1 +1 +DROP TABLE t1,t2,t3; +End of 5.0 tests. diff --git a/mysql-test/t/subselect4.test b/mysql-test/t/subselect4.test new file mode 100644 index 00000000000..ff4cdf3c439 --- /dev/null +++ b/mysql-test/t/subselect4.test @@ -0,0 +1,32 @@ +# General purpose bug fix tests go here : subselect.test too large + + +--echo # +--echo # Bug #46791: Assertion failed:(table->key_read==0),function unknown +--echo # function,file sql_base.cc +--echo # + +CREATE TABLE t1 (a INT, b INT, KEY(a)); +INSERT INTO t1 VALUES (1,1),(2,2); +CREATE TABLE t2 LIKE t1; +INSERT INTO t2 VALUES (1,1),(2,2); +CREATE TABLE t3 LIKE t1; + +--echo # should have 1 impossible where and 2 dependent subqueries +EXPLAIN +SELECT 1 FROM t1 +WHERE NOT EXISTS (SELECT 1 FROM t2 WHERE 1 = (SELECT MIN(t2.b) FROM t3)) +ORDER BY count(*); + +--echo # should not crash the next statement +SELECT 1 FROM t1 +WHERE NOT EXISTS (SELECT 1 FROM t2 WHERE 1 = (SELECT MIN(t2.b) FROM t3)) +ORDER BY count(*); + +--echo # should not crash: the crash is caused by the previous statement +SELECT 1; + +DROP TABLE t1,t2,t3; + + +--echo End of 5.0 tests. diff --git a/sql/sql_select.cc b/sql/sql_select.cc index b670e6e3637..9d5e67c9532 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -1474,12 +1474,8 @@ JOIN::optimize() } } - /* - If this join belongs to an uncacheable subquery save - the original join - */ - if (select_lex->uncacheable && !is_top_level_join() && - init_save_join_tab()) + /* If this join belongs to an uncacheable query save the original join */ + if (select_lex->uncacheable && init_save_join_tab()) DBUG_RETURN(-1); /* purecov: inspected */ }