Settings › Data › Query engine sets limits for the analysis engine that runs every report and AI query.

Setting	Meaning	Default
Show infinity as	Text shown for a division by zero or another infinite result, for example Infinity or -	Infinity
Show empty members as	Text shown for members without a name	(empty)
Max concurrent queries	Queries that may run at the same time; further queries wait	200
Max result rows	The most rows one query may return; 0 = no limit	500000
Query timeout (seconds)	A query running longer is stopped; 0 = no timeout. Reports wait this long plus 10 seconds before showing The query timed out.	300
UseAggregates / ReadAggregates	Let the engine read and use mapped aggregation tables; both must be on. Loaded models pick up the change after the model cache is cleared or the server restarts. See Use Aggregation Tables.	Off

Reset to default returns every engine setting to its factory value, including settings this page does not show. Save applies the changes.

A report page can lower the rows per component with Page → Settings → Performance → Max query records; the default for that is in System Configuration.

SQL statements of the engine

Each query sends SQL statements to the database through a shared set of engine threads (mondrian.rolap.maxSqlThreads, default 100). When all threads are busy, further statements wait in a queue; before 10.00 the whole query failed with The number of concurrent SQL statements … has been reached. One query may use at most mondrian.rolap.maxSqlThreadsPerQuery of the threads; the default 0 means half of maxSqlThreads, so one wide query cannot block the others. Both are set in bi-server/pentaho-solutions/system/datafor/mondrian.properties and take effect after a restart; they are not on this page.

Related: Empty Data and Error Messages