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Date: Mon, 15 Oct 2007 02:11:52 -0700 (PDT)
From: =?utf-8?Q?J=C3=B8rgen_L=C3=B8land_=28JIRA=29?= <jira@apache.org>
To: derby-dev@db.apache.org
Subject: [jira] Commented: (DERBY-3116) totalSpace not properly initialized
 in AllocPage
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    [ https://issues.apache.org/jira/browse/DERBY-3116?page=3Dcom.atlassian=
.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12534775 ]=20

J=C3=B8rgen L=C3=B8land commented on DERBY-3116:
--------------------------------------

Hi Knut Anders.

Patch d3116-1 looks correct to me, but it seems a little overkill to always=
 reinitiate the byte[] in StoredPage. Could you achieve the same thing by m=
oving the initSpace call from StoredPage#usePageBuffer to StoredPage#create=
Page? Alternatively make initSpace protected and call StoredPage#initSpace =
from CachedPage#setPageArray when the page is reused?

Another bug? In StoredPage#initSpace, slotEntrySize is used when setting ma=
xFieldSize. However, initSpace is called before slotEntrySize has been upda=
ted in usePageBuffer.=20

Not related to your patch: There is a problem with the Javadoc in AllocPage=
 (unclosed paragraph "<p"). Fixing that would show more javadoc in the html=
 files.

> totalSpace not properly initialized in AllocPage
> ------------------------------------------------
>
>                 Key: DERBY-3116
>                 URL: https://issues.apache.org/jira/browse/DERBY-3116
>             Project: Derby
>          Issue Type: Bug
>          Components: Store
>    Affects Versions: 10.4.0.0
>            Reporter: Knut Anders Hatlen
>            Priority: Minor
>         Attachments: d3116-1.diff
>
>
> There are some problems with the initialization of totalSpace in AllocPag=
e. It is initialized in StoredPage.initSpace() which is again called from S=
toredPage.usePageBuffer(), and it is set to the value returned from AllocPa=
ge.getMaxFreeSpace(). The problems are:
>   1) The calculation in getMaxFreeSpace() uses borrowedSpace, but when cr=
eateIdentity() is called on an AllocPage, borrowedSpace has not been initia=
lized when getMaxFreeSpace() is called and the calculated size is wrong.
>   2) When a page object is reused, usePageBuffer() is only called if a ne=
w byte array must be allocated (because the new page has a different size t=
han the old page). This means that the totalSize field gets the same value =
as in the old page if their sizes are equal, which is not necessarily corre=
ct.

--=20
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