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From "A B (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-3479) Changed/unexpected query plan when running test 'lang/predicatePushdown.sql'
Date Wed, 05 Mar 2008 19:17:44 GMT

     [ https://issues.apache.org/jira/browse/DERBY-3479?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

A B updated DERBY-3479:
-----------------------

    Attachment: d3479_1.diff

Per Mike's suggestion in the above email, namely:

"solutions include [...] call compress table on all tables before query which will update
all statistics and remove dependency on any outstanding per page row count updates"

I updated predicatePushdown.sql to compress all test tables before running any of the queries
which expect a specific query plan.  When I did that a lot of diffs showed up for predicatePushdown.out
in the form of:

  - Number of pages visited=1
  + Number of pages visited=2

I.e. seems we now visit one more page than we did without the compress.  That seems a tad
counter-intuitive to me (I figured compression would make it so that we visited fewer pages),
but given my lack of knowledge here I'm assuming that's an okay diff.

With this change I ran predicatePushdown.sql 10 times using ibm15 and it passed every time.
 I'm not sure how useful that is, though, since this same machine ran 6 times in a row without
failing even without this change...

Nonetheless, I'm posting the change as d3479_1.diff in case anyone has comments.  I'll probably
commit the patch sometime pretty soon since, even if it doesn't resolve this particular issue,
it sounds like it's a good idea to compress the tables anyway (per Mike's email)...

> Changed/unexpected query plan when running test 'lang/predicatePushdown.sql'
> ----------------------------------------------------------------------------
>
>                 Key: DERBY-3479
>                 URL: https://issues.apache.org/jira/browse/DERBY-3479
>             Project: Derby
>          Issue Type: Bug
>          Components: Regression Test Failure
>    Affects Versions: 10.4.0.0
>         Environment: OS: Solaris 10 6/06 s10x_u2wos_09a X86 64bits - SunOS 5.10 Generic_118855-14
> JVM: Sun Microsystems Inc., java version "1.6.0_04", Java(TM) SE Runtime Environment
(build 1.6.0_04-b12), Java HotSpot(TM) Client VM (build 10.0-b19, mixed mode)
>            Reporter: Ole Solberg
>         Attachments: d3479_1.diff
>
>
> Seen in tinderbox since r631930.
> See e.g. http://dbtg.thresher.com/derby/test/tinderbox_trunk16/jvm1.6/testing/testlog/SunOS-5.10_i86pc-i386/631932-derbyall_diff.txt
:
> *** Start: predicatePushdown jdk1.6.0_04 derbyall:derbylang 2008-02-28 14:02:49 ***
> 9285 del
> < 		Rows seen from the left = 20
> 9285a9285
> > 		Rows seen from the left = 10
> 9297 del
> < 			Rows seen from the right = 20
> 9297a9297
> > 			Rows seen from the right = 10
> 9299 del
> < 			Rows returned = 20
> 9299a9299
> > 			Rows returned = 10
> .
> .
> .

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