Current Path : /usr/opt/mysql57/mysql-test/include/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //usr/opt/mysql57/mysql-test/include/expect_qep.inc |
# 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; eval $query; 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;