[DERBY-3112] AllocPages have wrong minimumRecordSize

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 10.4.1.3
• Component/s: Store
• Assignee: Unassigned
• Reporter: Knut Anders Hatlen
• Created: 08/Oct/07 07:57
• Updated: 08/Apr/08 10:58
• Resolved: 08/Apr/08 10:58

Description

AllocPage.createPage() contains this code at its beginning:

super.createPage(newIdentity, args);

// args[0] is the format id
// args[1] is whether to sync the page to disk or not
// args[2] is the pagesize (used by StoredPage)
// args[3] is the spareSize (used by StoredPage)
// args[4] is the number of bytes to reserve for container header
// args[5] is the minimumRecordSize
// NOTE: the arg list here must match the one in FileContainer
int pageSize = args[2];
int minimumRecordSize = args[5];
borrowedSpace = args[4];

The variable minimumRecordSize is local and unused, so setting it has no effect. The local variable hides a field with the same name inherited from StoredPage. That field is initialized to args[4] when super.createPage() is called. According to the comment in AllocPage, args[4] is the number of bytes to reserve for the container header (aka borrowedSpace), not the minimum record size. (args[4] is however the minimum record size if the page is a plain StoredPage, that's why super.createPage() will use that value.) I therefore believe that this code intended to update StoredPage.minimumRecordSize, not a local, unused variable.

I don't know if this can lead to incorrect behaviour, but it doesn't look right.

Issue Links

• duplicates: DERBY-3589 AllocPage.createPage() doesn't initialize minimumRecordSize correctly