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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 12:24:36 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 12:24:36 +0000
commit06eaf7232e9a920468c0f8d74dcf2fe8b555501c (patch)
treee2c7b5777f728320e5b5542b6213fd3591ba51e2 /mysql-test/include/expect_qep.inc
parentInitial commit. (diff)
downloadmariadb-06eaf7232e9a920468c0f8d74dcf2fe8b555501c.tar.xz
mariadb-06eaf7232e9a920468c0f8d74dcf2fe8b555501c.zip
Adding upstream version 1:10.11.6.upstream/1%10.11.6
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+# include/expect_qep.inc
+#
+# SUMMARY
+#
+# Designed to be used together with include/check_qep.inc
+#
+# $query should be assigned a select statement using
+# straight_join to force the tables to be joined in most
+# optimal order.
+#
+# expect_qep.inc will then store the estimated 'Last_query_cost'
+# and total # 'Handler_read%' for this straight_joined query.
+#
+# We should then assign a non-straight_join'ed version of
+# the same query to $query and execute it using
+# 'include/check_qep.inc'. Its estimated cost and
+# #handler_reads will then be verified against the
+# previous straight_joined query.
+#
+# USAGE
+#
+# let $query= <select straight_join optimal statement>;
+# --source include/expect_qep.inc
+# let $query= <select statement>;
+# --source include/check_qep.inc
+#
+# EXAMPLE
+# t/greedy_optimizer.test
+#
+
+flush status;
+eval EXPLAIN $query;
+--disable_ps2_protocol
+eval $query;
+--enable_ps2_protocol
+
+let $best_cost=
+ query_get_value(SHOW STATUS LIKE 'Last_query_cost', Value, 1);
+
+--disable_warnings
+let $best_reads=
+`select sum(variable_value)
+ from information_schema.session_status
+ where VARIABLE_NAME like 'Handler_read%'`;
+--enable_warnings
+
+#echo Expect, cost: $best_cost, Handler_reads: $best_reads;