[ https://issues.apache.org/jira/browse/DERBY-2836?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Laura Stewart updated DERBY-2836: --------------------------------- Attachment: rtunproper40688.html ctunperf816059.html derby2836.diff > Documentation of derby.storage.pageSize should mention that the default is > dynamic > ---------------------------------------------------------------------------------- > > Key: DERBY-2836 > URL: https://issues.apache.org/jira/browse/DERBY-2836 > Project: Derby > Issue Type: Improvement > Components: Documentation > Affects Versions: 10.2.2.0 > Reporter: Kurt Huwig > Assignee: Laura Stewart > Fix For: 10.4.0.0 > > Attachments: ctunperf816059.html, derby2836.diff, > rtunproper40688.html, rtunproper81359.html > > > The documention of derby.storage.pageSize at > docs/html/tuning/rtunproper40688.html says: > Default > 4096 bytes. > But this page docs/html/tuning/ctunperf816059.html hints, that this default > is not necessarily the one to be used: > "Derby autotunes the database pagesize. If you have long columns, the default > pagesize for the table is set to 32K. Otherwise, the default is 4K." > Also the documentation of derby.storage.pageCacheSize at > docs/html/tuning/rtunproper81359.html does not mention this: > "When increasing the size of the page cache, you typically have to allow more > memory for the Java heap when starting the embedding application (taking into > consideration, of course, the memory needs of the embedding application as > well). For example, using the default page size of 4K, a page cache size of > 2000 pages will require at least 8 MB of memory (and probably more, given the > overhead)." > We had one machine crashing, because we expected the page size to be the > default of 4096. After 2 hours of testing, I found out that for my particular > example, the page size is set to 32K. So having a note added would have at > least saved me some time and hassle. > I recommend to add the sentence > "Derby autotunes the database pagesize. If you have long columns, the default > pagesize for the table is set to 32K. Otherwise, the default is 4K." > to both the documentation of derby.storage.pageSize and > derby.storage.pageCacheSize -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.