If I had to guess, I'd say that this was a locking issue.  If you have two
threads that need a query that doesn't exist yet then they could both try to
create it (though why it would have different names is downright weird) and
write them to disk.

Or, if a second thread needs a query that a first has not yet completely
written to disk they would get an empty or partial file.

If this has been logged as a ticket then that's the best thing for now.

Doug

On 4/4/07, Dave Shuck <[EMAIL PROTECTED]> wrote:

Mark, we too have had occasional issues with what we feel are empty
queries (an error in Sybase that is often related to empty queries) but
haven't pinpointed the exact cause/issue yet.  Sorry that I don't have
anything constructive to add, but you aren't alone.   Thanks for sharing
your notes as we will certainly be adding it to our discussion.

~Dave


On 4/3/07, Mark Stanton <[EMAIL PROTECTED]> wrote:
>
> Hi All
>
> We've noticed a couple of strange/intermittent  errors when we are
> running reactor under load.
>
> The first is with
>
> 
http://trac.reactorframework.org/reactor/browser/trunk/reactor/iterator/iterator.cfc#L638
> .
> If you an iterator object in session or application scope one thread
> could modify the value of variables.column list while the another
> thread is mid loop.
>
> This is giving us errors such as:
>
>     * Error Executing Database Query - Query Of Queries syntax error
> Encountered "FROM. Incorrect Select List, Incorrect select column
>     * Error Executing Database Query - Query Of Queries syntax error
> Encountered "[. Incorrect Select List, Incorrect select column
>
> The second issue has left me really confused - but hopefully someone
> can shed some light if I describe what I am seeing.
>
> This only happens when I delete all the generated files on the server
> and then run a spider over the site downloading pages as fast as I
> can.
>
> What happens is various places in the site start reporting errors such
> as:
>
>     * Error Executing Database Query. - Can not issue empty query
>
> If I go into the project/projectName/Queries folder and delete
> everything the problem goes away.
>
> Digging a little deeper yesterday I decided to remove files from this
> folder one at a time until the problem disappeared.
>
> To start with I had the following in my Queries directory:
>
> elderberry1# ls -l
> -rw-r--r--   1 nobody   nobody       418 Apr  3 17:41
> mysql4_32A555A0E0A4EB3922128461A89E6758.cfm
> -rw-r--r--   1 nobody   nobody      1060 Apr  3 20:55
> mysql4_3BEAC4648F61B3A87578FDFF4DF7554E.cfm
> -rw-r--r--   1 nobody   nobody       297 Apr  3 20:58
> mysql4_44F979C97340DA3CE0D2021AD0ACAA30.cfm
> -rw-r--r--   1 nobody   nobody       189 Apr  3 21:00
> mysql4_52C2EE5CEB0B9E9771C39DDDC6D39805.cfm
> -rw-r--r--   1 nobody   nobody       287 Apr  3 20:58
> mysql4_541D944DE40657C9F4485F61D73879E5.cfm
> -rw-r--r--   1 nobody   nobody      1011 Apr  3 20:58
> mysql4_545D709DDFB7FB9A39D83DE61B51E807.cfm
> -rw-r--r--   1 nobody   nobody       512 Apr  3 17:41
> mysql4_9749F8EF18553997508285FEB9E7AF75.cfm
> -rw-r--r--   1 nobody   nobody      2660 Apr  3 17:41
> mysql4_9C8A9EF73C5E5FC54B256A0D40D7D363.cfm
> ...etc...
> -rw-r--r--   1 nobody   nobody       488 Apr  3 20:56
> mysql4_FC97C2FFA26AB9EA20FC175828F817F5.cfm
> drwxr-xr-x   2 root     root        1024 Apr  3 21:11 tmp
>
> I moved the files one at a time into the tmp folder, refreshing the
> page that was throwing the error until the error disappeared.
>
> elderberry1# mv mysql4_32A555A0E0A4EB3922128461A89E6758.cfm tmp/
> elderberry1# mv mysql4_3BEAC4648F61B3A87578FDFF4DF7554E.cfm tmp/
> elderberry1# mv mysql4_44F979C97340DA3CE0D2021AD0ACAA30.cfm tmp/
> <<<<<<<<<<<<<< THIS FIXED IT!
>
> The mysql4_44F979C97340DA3CE0D2021AD0ACAA30.cfm was regenerated and
> the error went away. I checked the contents of the new file with the
> old one expecting them to be and they were identical:
>
> elderberry1# cat mysql4_44F979C97340DA3CE0D2021AD0ACAA30.cfm
> SELECT  `Tender_Location`.`TenderUUID` AS `TenderUUID`,
> `Tender_Location`.`LocationUUID` AS `LocationUUID` FROM
> `atii`.`Tender_Location` AS `Tender_Location` WHERE
> `Tender_Location`.`TenderUUID` = <cfqueryparam
> cfsqltype="cf_sql_varchar" maxlength="36"
> value="#arguments.Query.getValue(1)#" />
>
> elderberry1# cd tmp
> elderberry1# cat mysql4_44F979C97340DA3CE0D2021AD0ACAA30.cfm
> SELECT  `Tender_Location`.`TenderUUID` AS `TenderUUID`,
> `Tender_Location`.`LocationUUID` AS `LocationUUID` FROM
> `atii`.`Tender_Location` AS `Tender_Location` WHERE
> `Tender_Location`.`TenderUUID` = <cfqueryparam
> cfsqltype="cf_sql_varchar" maxlength="36"
> value="#arguments.Query.getValue(1)#" />
>
> This left me very puzzled. I checked the directory listing again and
> noticed that there were two new files:
>
> elderberry1# cd ..
> elderberry1# ls -l
> total 54
> -rw-r--r--   1 nobody   nobody       418 Apr  3 21:12
> mysql4_32A555A0E0A4EB3922128461A89E6758.cfm
> -rw-r--r--   1 nobody   nobody       297 Apr  3 21:12
> mysql4_44F979C97340DA3CE0D2021AD0ACAA30.cfm
> -rw-r--r--   1 nobody   nobody       189 Apr  3 21:00
> mysql4_52C2EE5CEB0B9E9771C39DDDC6D39805.cfm
> -rw-r--r--   1 nobody   nobody       287 Apr  3 20:58
> mysql4_541D944DE40657C9F4485F61D73879E5.cfm
> -rw-r--r--   1 nobody   nobody      1011 Apr  3 20:58
> mysql4_545D709DDFB7FB9A39D83DE61B51E807.cfm
> -rw-r--r--   1 nobody   nobody       512 Apr  3 17:41
> mysql4_9749F8EF18553997508285FEB9E7AF75.cfm
> -rw-r--r--   1 nobody   nobody       450 Apr  3 21:12
> mysql4_9A42F5B932DD262F4B475143BC30D5CC.cfm     <<<<<<<<<<<<<< NEW!
> -rw-r--r--   1 nobody   nobody       804 Apr  3 21:12
> mysql4_9A7CA2B2B74B1B6D46F409CD8020D6CB.cfm     <<<<<<<<<<<<<< NEW!
> -rw-r--r--   1 nobody   nobody      2660 Apr  3 17:41
> mysql4_9C8A9EF73C5E5FC54B256A0D40D7D363.cfm
> ...etc...
> -rw-r--r--   1 nobody   nobody       488 Apr  3 20:56
> mysql4_FC97C2FFA26AB9EA20FC175828F817F5.cfm
> drwxr-xr-x   2 root     root        1024 Apr  3 21:12 tmp
>
> So why was the presence of the mysql_44F... file preventing the
> generation of these two other files?
>
> I've had a look and as far as I can tell this would be related to
>
> 
http://trac.reactorframework.org/reactor/browser/trunk/reactor/query/query.cfc#L57
> ,
> but beyond that I am stumped.
>
> If anyone has any ideas I'd love to hear them.
>
>
> Cheers
>
> Mark
>
>
> Mark Stanton
> Gruden Pty Ltd
> http://www.gruden.com
>
>
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>
>


--
~Dave Shuck
[EMAIL PROTECTED]
www.daveshuck.com

Where's your Spot?
www.instantspot.com
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Doug Hughes


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