I have made custom module to generate hundreds or thousands of nodes (using Batch API) to test various loads.
After deleting 10000 nodes (again with custom Batch) I have noticed some errors in watchdog log during cron runs:
PDOException: SQLSTATE[42803]: Grouping error: 7 ERROR: column "node.type" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: SELECT node.type AS type, node.uid AS uid, COUNT(*) AS expre... ^: SELECT node.type AS type, node.uid AS uid, COUNT(*) AS expression FROM {comment} c INNER JOIN {node} node ON c.nid = node.nid WHERE (c.nid = :db_condition_placeholder_0) AND (c.status = :db_condition_placeholder_1) AND (node.language IN (:db_condition_placeholder_2, :db_condition_placeholder_3)) AND (node.type != :type) AND (node.type != :type) AND (node.type != :type) AND (node.type != :type) ; Array ( [:db_condition_placeholder_0] => 8 [:db_condition_placeholder_1] => 1 [:db_condition_placeholder_2] => lt [:db_condition_placeholder_3] => und [:type] => article ) - PagerDefault->execute() (eilutė 74 iš /var/www/clients/client0/web1/web/includes/pager.inc).I've tried to run cron directly in browser and I got this:
Uncaught exception thrown in shutdown function.
PDOException: SQLSTATE[54001]: Statement too complex: 7 ERROR: stack depth limit exceeded HINT: Increase the configuration parameter "max_stack_depth" (currently 2048kB), after ensuring the platform's stack depth limit is adequate.: DELETE FROM {search_total} WHERE ( (word = :db_condition_placeholder_0) OR (word = :db_condition_placeholder_1) OR (word = :db_condition_placeholder_2) OR (word = :db_condition_placeholder_3) OR (word = :db_condition_placeholder_4) OR (word = :db_condition_placeholder_5) OR (word = :db_condition_placeholder_6) OR (word = :db_condition_placeholder_7) OR (word = :db_condition_placeholder_8) OR
... and so on ...
OR (word = :db_condition_placeholder_9994) ); Array ( [:db_condition_placeholder_0] => 5 [:db_condition_placeholder_1] => 9 [:db_condition_placeholder_2] => 10 [:db_condition_placeholder_3] => 11 [:db_condition_placeholder_4] => 12 [:db_condition_placeholder_5] => 13 [:db_condition_placeholder_6] => 14 [:db_condition_placeholder_7] => 15 [:db_condition_placeholder_8] => 16 [:db_condition_placeholder_9] => 17 [:db_condition_placeholder_10] => 18 [:db_condition_placeholder_11] => 19 [:db_condition_placeholder_12] => 20 [:db_condition_placeholder_13] => 21 [:db_condition_placeholder_14] => 22 [:db_condition_placeholder_15] => 23 [:db_condition_placeholder_16] => 24
... and so on ...
[:db_condition_placeholder_9993] => 9999 [:db_condition_placeholder_9994] => 10000 ) in search_update_totals() (line 396 of /var/www/clients/client0/web1/web/modules/search/search.module).