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https://issues.apache.org/jira/browse/DERBY-6425?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14241343#comment-14241343
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Mike Matrigali commented on DERBY-6425:
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The main reason for checksuming pages derby writes is to catch the problem
where derby page size is larger
than the filesystem page size. In this case at some layer between the write
call that derby issues in java a single
write of a page is broken up into multiple writes of smaller blocks to the file
system. If somehow only some of these
blocks make it to the file and not others, the checksum will catch the error.
It seems like there are at least 3 possibilities here:
1) somehow with write cache enabled the kill of the process somehow happened
just at the "right" time in
the system
to allow some of the smaller blocks to be written to cache but not the
others. This is very low level code
that derby has no control over. Also this low level code may not have any
idea about write caching as it
happens at yet another level.
2) there is an actual disk problem where a bad bit gets read and/or written and
checksum is catching it. Have
you run diagnostics on your disk?
3) there is some bug in derby.
Would it be possible for you to run your test with write caching disabled and
see if you can reproduce the problem?
> DB got corrupted during the heavy operations.
> ---------------------------------------------
>
> Key: DERBY-6425
> URL: https://issues.apache.org/jira/browse/DERBY-6425
> Project: Derby
> Issue Type: Bug
> Components: Store
> Affects Versions: 10.9.1.0
> Environment: Suse 10.
> Reporter: patil devidas
> Priority: Critical
>
> ------------ BEGIN SHUTDOWN ERROR STACK -------------
> ERROR XSDG2: Invalid checksum on Page Page(5482,Container(0, 2032)),
> expected=3,506,219,016, on-disk version=492,279,644, page dump follows: Hex
> dump:
> 00000000: 0075 0000 0001 0000 0000 0000 0067 0022 .u...........g..
> 00000010: 0000 0028 0000 0000 0000 0000 0000 0000 ................
> 00000020: 0000 0000 0001 0000 0000 0000 0000 0000 ................
> 00000030: 0000 0000 0000 0000 0000 0000 0406 000a ................
> 00000040: 0026 0024 6139 3630 3261 6266 2d33 3163 ....a9602abf.31c
> 00000050: 662d 3131 6533 2d38 3363 632d 6231 3935 f.11e3.83cc.b195
> 00000060: 6138 3139 3263 6334 000b 0009 434f 4d50 a8192cc4....COMP
> 00000070: 4c45 5445 4400 0c07 dd0a 0a00 1310 0c05 LETED...........
> 00000080: 4e08 4000 0c07 dd0a 0a00 1310 1c03 1975 N..............u
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