Tickets :: Comment on [#14368] Improve EAS performance with large History tables

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Comment	> This query for example takes over 3 seconds to complete: > > SELECT DISTINCT object_uid, history_id FROM horde_histories WHERE > history_modseq > 956528 AND history_modseq <= 2191866 AND > history_action = 'add' AND object_uid LIKE > 'kronolith:_J9sL_cb_Xuk0gpnaFfIGA9:%'; > > Our MySQL server uses the history_action index, but even if I force > MySQL to use the object_uid index it's still over 1 second. The > moqseq 956528 is from April 2015. I hoped there is a way to prevent > checking the same history entries every 15 seconds for a year, at > least in these cases when a user doesn't use a collection. > >> >> This confuses me. We filter the history query on the calendar(s) >> being checked, so the current value of modSeq should be >> inconsequential since the query will only return entries with higher >> modSeq values AND matching the calendar. Could you clarify where you >> see loq modSeq values increasing "the number of history entries that >> has to be checked"? >> >> >>> These lookups can be reduced if we update the sync state from time to >>> time. This could be done if we override the getChanges method in >>> Horde_ActiveSync_State_Sql: >>> >>> public function getChanges(array $options = array()) >>> { >>> parent::getChanges($options); >>> if ($this->_type == Horde_ActiveSync::REQUEST_TYPE_PING && >>> empty($this->_changes) && >>> $this->_lastSyncStamp < $this->_thisSyncStamp - 10000) { >>> >>> $this->_lastSyncStamp = $this->_thisSyncStamp; >>> $this->_type = Horde_ActiveSync::REQUEST_TYPE_SYNC; >>> $this->save(); >>> $this->_type = Horde_ActiveSync::REQUEST_TYPE_PING; >>> } >>> return $this->_changes; >>> } >>> >>> The type change is a bit ugly, but the save method would clear the >>> sync_data otherwise. That could be changed in the save method. >> >> We can't change the request type. This would affect a number of other >> things, including preventing mirroring client-sourced changes back to >> the client and the handling of pending changes. It would possible >> (though admittedly a very small chance) that this could overwrite >> any existing pending changes in the state. Basically this changes the >> sync state without changing the synckey, which we cannot do. >> >>> The update might only be needed on collections that support modseq, >>> but the connector is not available from the state. I don't know if it >>> would cause problems with mail folders, every 10000 seconds would be >>> 8 times per day which would be more than necessary. >> >
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