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Key: CORE-1696
Type: Bug Bug
Status: Closed Closed
Resolution: Fixed
Priority: Major Major
Assignee: Roman Simakov
Reporter: Roman Simakov
Votes: 0
Watchers: 0
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Firebird Core

Deadlock in LM by using nbackup utility

Created: 17/Jan/08 07:55 AM   Updated: 08/Nov/09 06:23 PM
Component/s: Engine
Affects Version/s: 2.1.0
Fix Version/s: 2.5 Beta 1

Time Tracking:
Not Specified

Environment: Classic server


 Description  « Hide
Deadlock description: Process A inserts records into a table. It keeps LCK_read lock on LCK_backup_database and can fetch other pages since NBackupState use recursive locks. So process A calls FETCH_LOCK for a page (for example PP) and waits it if a process B already uses this page. On the other hand process B can have called FETCH_LOCK and must read the page from disk. To do this it must request LCK_backup_database with LCK_read level for status receiving. In this case process B have to wait if third process N already request LCK_backup_database with LCK_write level.

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Roman Simakov added a comment - 17/Jan/08 08:00 AM - edited
To resolve the problem nbackup must have an order of lock requesting for LCK_bdb and LCK_backup_database.