[DERBY-3015] Concurrent select and insert deadlock on index

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 10.3.1.4
• Component/s: Store
• Assignee: Unassigned
• Reporter: Kurt Huwig
• Created: 18/Aug/07 14:49
• Updated: 18/Aug/07 23:28
• Resolved: 18/Aug/07 22:02

Description

From the derby mailinglist

The attached test is an attempt to simulate a typical data processing
application, it consists of:

• an insert thread that inserts records in batch
• a select thread that 'processes' the records inserted by the other
  thread: 'select * from table where id > ?'

The test deadlocks. After examining them, I think that:

• the select thread holds an S lock on the root of the PK index: (1,1)
• the select thread waits for an S lock on one of the uncommitted inserts

• the insert thread holds X locks on the inserted records
• the insert thread tries to split the btree root of the PK index:
  (1,1) by acquiring an X lock, so it's a deadlock

I've got the same problem nearly every day in my application, therefore I simplified the example file from the mailinglist. I did also try it with MySQL without a deadlock.

Issue Links

• duplicates: DERBY-2991 Index split deadlock