[
https://issues.apache.org/jira/browse/DERBY-5473?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13699059#comment-13699059
]
Kathey Marsden commented on DERBY-5473:
---------------------------------------
Verified this is still an issue on trunk 10.11 but appears worse with more than
500 pages allocated. I don't know if that perhaps is due to using a faster
machine. In general though I have seen several user cases where this paradigm
of a small dataset that is getting updated with ever increasing values causes
significant growth that can only be mitigated with periodic compress.
> Index growth can occur with update of ever increasing values
> -------------------------------------------------------------
>
> Key: DERBY-5473
> URL: https://issues.apache.org/jira/browse/DERBY-5473
> Project: Derby
> Issue Type: Bug
> Components: Store
> Affects Versions: 10.5.3.2, 10.6.2.3, 10.7.1.4, 10.8.3.0, 10.9.1.0
> Reporter: Kathey Marsden
> Labels: derby_triage10_9
> Attachments: ReproIdxGrowth.java
>
>
> On a table with an BIGINT Index that is updated quickly with every
> increasing values the index can grow and space not be reclaimed.
> Attaching a reproduction for this issue ReproIdxGrowth.
> The program has a single thread that iteratively updates 5 rows in a table
> with a time value.
> PreparedStatement ps = conn.prepareStatement(
> "UPDATE T SET LAST_SYNC_TIME = ?, NUM_SYNCS = ? WHERE ACCOUNT_ID =
> ?");
> ResultSet rs = s.executeQuery("SELECT ACCOUNT_ID, NUM_SYNCS FROM T");
> while( rs.next()) {
> int account = rs.getInt(1);
> int prevNumSync = rs.getInt(1);
> ps.setLong(1, new Date().getTime());
> ps.setInt(2,prevNumSync++);
> ps.setInt(3, account);
> ps.executeUpdate();
> }
> After 50,000 iterations we end up with 150 pages allocated for the just the 5
> rows, possibly because it cannot get the table lock to rebalance the tree.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
