MySQL Bugs: #13548: Larger Result Sets Cause Crashes

Bug #13548	Larger Result Sets Cause Crashes
Submitted:	27 Sep 2005 23:40	Modified:	6 Oct 2005 15:17
Reporter:	Chris Kapsalis	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Query Browser	Severity:	S2 (Serious)
Version:	1.1.12	OS:	Linux (Fedora Core 3)
Assigned to:	Alfredo Kojima	CPU Architecture:	Any

Description:
Performing queries with result sets in the thousands of rows (10K to 20K+) makes the query browser perform extremely slowly at first.  Attempting to work within the result set or performing other queries, while retaining the previous result set eventually results in the application disappearing (crashing) without any error messages.

How to repeat:
Perform a multi-table (3+) query resulting in thousands of rows (the more rows in the result set, the easier it is to reproduce the problem). 

Review the result set and attempt to update some records. Sometimes it will crash immediately when you click on a cell to edit or sometimes it will crash when you attempt to save the changes.

Note that if you close the tab with the large result set, the query browser appears to return to normal behavior (although, even with smaller result sets, editing a row can make it crash at that point).

The problems you experience probably come from making queries too large to fit in the available memory. Try using the LIMIT clause on your queries to work on a smaller number of rows per time. 

A limit for the max amount of memory used by a resultset has also been added (1/2 of the physical RAM available), so queries will not grow indefinitely.