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Diffstat (limited to 'mysql-test/t/show_explain.test')
| -rw-r--r-- | mysql-test/t/show_explain.test | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/mysql-test/t/show_explain.test b/mysql-test/t/show_explain.test new file mode 100644 index 00000000000..38fc8ff4c8e --- /dev/null +++ b/mysql-test/t/show_explain.test @@ -0,0 +1,211 @@ +# +# Tests for SHOW EXPLAIN FOR functionality +# +--source include/have_debug.inc + +--disable_warnings +drop table if exists t0, t1; +--enable_warnings + +# +# Testcases in this file do not work with embedded server. The reason for this +# is that we use the following commands for synchronization: +# +# set @show_explain_probe_select_id=1; +# set debug_dbug='d,show_explain_probe_join_exec_start'; +# send select count(*) from t1 where a < 100000; +# +# When ran with mysqltest_embedded, this translates into: +# +# Thread1> DBUG_PUSH("d,show_explain_probe_join_exec_start"); +# Thread1> create another thread for doing "send ... reap" +# Thread2> mysql_parse("select count(*) from t1 where a < 100000"); +# +# That is, "select count(*) ..." is ran in a thread for which DBUG_PUSH(...) +# has not been called. As a result, show_explain_probe_join_exec_start does not fire, and +# "select count(*) ..." does not wait till its SHOW EXPLAIN command, and the +# test fails. +# +-- source include/not_embedded.inc + + +create table t0 (a int); +insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); +create table t1 (a int); +insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C; +alter table t1 add b int, add c int, add filler char(32); +update t1 set b=a, c=a, filler='fooo'; +alter table t1 add key(a), add key(b); + +# +# Try killing a non-existent thread +# +--error ER_NO_SUCH_THREAD +show explain for 2*1000*1000*1000; + +--error ER_NOT_SUPPORTED_YET +show explain for (select max(a) from t0); + +# +# Setup two threads and their ids +# +let $thr1=`select connection_id()`; +connect (con1, localhost, root,,); +connection con1; +let $thr2=`select connection_id()`; +connection default; + +# SHOW EXPLAIN FOR <idle thread> +--error ER_ERROR_WHEN_EXECUTING_COMMAND +evalp show explain for $thr2; + +# SHOW EXPLAIN FOR <ourselves> +--error ER_ERROR_WHEN_EXECUTING_COMMAND +evalp show explain for $thr1; + +let $wait_condition= select State='show_explain_trap' from information_schema.processlist where id=$thr2; + +# +# Test SHOW EXPLAIN for simple queries +# +connection con1; +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send select count(*) from t1 where a < 100000; + +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + + +send select max(c) from t1 where a < 10; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + + +--echo # We can catch EXPLAIN, too. +set @show_expl_tmp= @@optimizer_switch; +set optimizer_switch='index_condition_pushdown=on,mrr=on,mrr_sort_keys=on'; +send explain select max(c) from t1 where a < 10; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; +set optimizer_switch= @show_expl_tmp; + + +--echo # UNION, first branch +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send explain select a from t0 A union select a+1 from t0 B; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + + +--echo # UNION, second branch +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send explain select a from t0 A union select a+1 from t0 B; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + + +--echo # Uncorrelated subquery, select +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send select a, (select max(a) from t0 B) from t0 A where a<1; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + + +--echo # Uncorrelated subquery, explain +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send explain select a, (select max(a) from t0 B) from t0 A where a<1; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + +--echo # correlated subquery, select +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + +--echo # correlated subquery, explain +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + +--echo # correlated subquery, select, while inside the subquery +set @show_explain_probe_select_id=2; # <--- +set debug_dbug='d,show_explain_probe_join_exec_start'; +send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + +--echo # correlated subquery, explain, while inside the subquery +set @show_explain_probe_select_id=2; +set debug_dbug='d,show_explain_probe_join_exec_start'; +send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + + +--echo # correlated subquery, explain, while inside the subquery +set @show_explain_probe_select_id=1; +set debug_dbug='d,show_explain_probe_join_exec_end'; +send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1; +connection default; +--source include/wait_condition.inc +evalp show explain for $thr2; +connection con1; +reap; + +# TODO: explain in the parent subuqery when the un-correlated child has been +# run (and have done irreversible cleanups) + +# TODO: hit JOIN::optimize for non-select commands: UPDATE/DELETE, SET. + + +## TODO: Test this: multiple SHOW EXPLAIN calls in course of running of one select +## +## TODO: Test this: have several SHOW EXPLAIN requests be queued up for a +## thread and served together. + +## TODO: SHOW EXPLAIN while the primary query is running EXPLAIN EXTENDED/PARTITIONS +## + +drop table t0,t1; 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