[DERBY-1679] Improve usage of file resources when sorting

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 10.0.2.0, 10.0.2.1, 10.1.1.0, 10.1.2.1, 10.1.3.1, 10.2.1.6
• Component/s: Store
• Assignee: Unassigned
• Reporter: Sunitha Kambhampati
• Created: 11/Aug/06 20:11
• Updated: 21/Jun/07 23:23

Description

Currently each sort merge run is put into a separate file. Worst case, the sot module can use 512 open files per connection.
This jira is to investigate how to improve file resources usage. Derby server should maintain some control on open files.

Mike suggested that one solution could be to tie the open files into something like the open file cache in the store, or maybe just store all the sort runs in a single file - i think they are written sequentially so may not be hard to do using existing streamed file support in the store.

Also see derby-1661.

Issue Links

• is related to: DERBY-1676 Dynamically change the max merge runs in a merge phase during external sorting.
• is related to: DERBY-1677 Investigate increasing the memory limit that is used to calculate the sortbuffer size for sorting.
• relates to: DERBY-1661 Create index on large tables fails with too many open files , FileNotFoundException.