Hi, Sergei! On Oct 18, Sergei Petrunia wrote: > Hello, > > After recent changes in the [SHOW] EXPLAIN architecture in MariaDB, it became > really easy to add an option to print EXPLAIN(*) output into the slow query > log, > so I went ahead and implemented it. > > @@log_slow_verbosity has got a 'explain' flag, and if it is on, the slow query > log entries look like this: > > # Time: 131017 21:26:02 > # User@Host: root[root] @ localhost [] > # Thread_id: 2 Schema: dbt3sf1 QC_hit: No > # Query_time: 5.535819 Lock_time: 0.000350 Rows_sent: 1 Rows_examined: > 65633 > ## <explain> > ## id select_type table type possible_keys key key_len ref > rows Extra > ## 1 SIMPLE nation ref PRIMARY,n_name n_name 26 const 1 > Using where; Using index > ## 1 SIMPLE customer ref PRIMARY,i_c_nationkey i_c_nationkey > 5 dbt3sf1.nation.n_nationkey 25124 Using index > ## 1 SIMPLE orders ref i_o_custkey i_o_custkey 5 > dbt3sf1.customer.c_custkey 7 Using index > ## </explain> > SET timestamp=1382030762; > select count(*) from customer, orders, nation where c_custkey=o_custkey and > c_nationkey=n_nationkey and n_name='GERMANY'; > > It seems, pt-slow-query-log has no problem parsing this. > > Open questions: > > - Is this syntax OK?
Yes, assuming you use tabs as column separators, not spaces. > - Currently, some statements (like SHOW KEYS) print a dumb explain that > shows that full table scan is used. There is a suggestion to not print > EXPLAIN for any SHOW statements. Is this ok? Yes. If users will complain we can always change it back later. Regards, Sergei _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
