Hi!

Maybe the select starts the garbage collection, and it slows down it. When you run backup without -g it does the garbage collection too, so could fix the problem. (Are you running it with / without -g?)


* How many updates / delete run average on that table? Is it often changed or not?
* Can business logic cause many rollback transactions?
* Are you running long running transactions, which can block the garbage collection?
* Run gstat -h and check transaction markers (Oldest transactin, Oldest active, Oldest snapshot, Next transaction, Sweep interval) when the select hang to check this theory.

http://www.firebirdsql.org/pdfmanual/html/gfix-housekeeping.html

András

From: firebird-support@yahoogroups.com [mailto:firebird-support@yahoogroups.com]
Sent: Saturday, December 30, 2017 12:42 PM
To: firebird-support@yahoogroups.com
Subject: [firebird-support] Select freezes



Hello.



My software is running on a client and sometimes something happens and a SELECT command in a table (only in this table) freezes. Then I just do a backup (only a backup, without restore) and the command runs correct again.



What could it be?



Thank you.







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