Last modified: 2014-05-12 11:37:05 UTC
The following query form is starting to run slow on the x1 cluster for flowdb: flowdb> explain SELECT /* Flow\Formatter\ContributionsQuery::queryRevisions */ * FROM `flow_revision`,`flow_workflow`,`flow_tree_node` WHERE (rev_user_id > 1509667) AND (rev_id < '*�*�\0\0\0\0\0\0') AND workflow_wiki = 'mediawikiwiki' AND rev_type = 'post-summary' ORDER BY rev_id DESC LIMIT 51\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: flow_revision type: ref possible_keys: PRIMARY,flow_revision_user,flow_revision_type_id key: flow_revision_type_id key_len: 18 ref: const rows: 55 Extra: Using index condition; Using where; Using filesort *************************** 2. row *************************** id: 1 select_type: SIMPLE table: flow_workflow type: ref possible_keys: flow_workflow_lookup key: flow_workflow_lookup key_len: 18 ref: const rows: 649 Extra: Using index condition *************************** 3. row *************************** id: 1 select_type: SIMPLE table: flow_tree_node type: index possible_keys: NULL key: flow_tree_constraint key_len: 13 ref: NULL rows: 20065 Extra: Using index 3 rows in set (0.26 sec) While tolerable now thanks to optimizer choosing index condition pushdown, it looks like a candidate for future pain. Should it be possible to trigger a three-way cross join?
