Chuck
On Mar 31, 2008, at 2:21 PM, Dov Rosenberg wrote:
Is there a queue where requests get stored in or some sort of timeoutwaiting for the lock to release? Or is the failure an outright exception?Dov Rosenberg On 3/31/08 4:25 PM, "Chuck Hill" <[EMAIL PROTECTED]> wrote:On Mar 31, 2008, at 1:15 PM, Dov Rosenberg wrote:I guess the real problem is trying to run multithreaded apps against asingle threaded EOF stack. Unless we start using multiple EOF stacks we could potentially have other performance problems lurking in the shadowsMore likely from slow fetches and repeated tripping of single faults than this. If you are doing lot of these counts, it would make sense to create a separate EOF stack just for them. ChuckOn 3/31/08 3:39 PM, "Chuck Hill" <[EMAIL PROTECTED]> wrote:That is how you lock the EOF stack. While the stack is locked, no other thread can fetch / save. This same lock happens during all fetch or save operations. Chuck On Mar 31, 2008, at 12:09 PM, Dov Rosenberg wrote:Taking a look at the new code – I agree it looks a bit safer thanthe old code. What is the implication for doing an EODatabaseContextlock in a multi threaded app? Will that cause any problems if multiple sessions are trying to do something similar concurrently? Dov Rosenberg On 3/30/08 5:56 PM, "Mike Schrag" <[EMAIL PROTECTED]> wrote:It's not thread safe, and Wonder's implementation doesn't actuallywork like this anymore (your code is based on a version from last year sometime) ... See ERXEOControlUtilities._aggregateFunctionWithQualifier for an example of how to do it properly (we actually create an attribute without adding it to the entity) ms On Mar 30, 2008, at 5:43 PM, Dov Rosenberg wrote:We have some code that we are using from Project Wonder (I think)that adds an attribute programmatically to an EOEntity to do things like count, max, etc. (See below). We were doing a load test on our application and started throwing errors because adifferent query was submitted using the extra attribute. It seems that making changes to the EOModel is not thread safe. If that isthe case is there anything we can do to use this code? Or shouldwe dump this and build a regular fetch for the aggregate data. Anythooughts or insights would be a huge help. Query that was generated in error – notice the COUNT() attribute embedded in the query incorrectly "SELECT t0.ACTUALRATING, t0.BODY, t0.CLOSED, t0.DATEADDED, t0.DATEMODIFIED, t0.FORUMID, t0.IPADDRESS, t0.LOCALEID, t0.MODERATE, COUNT(t0.RECORDID), t0.PUBLISHED, t0.RECORDID, t0.STATUS, t0.TITLE, t0.TYPE, t0.USERID, t0.USERNAME, t0.USERNICKNAME, t0.WEIGHTEDRATING FROM DBTOPIC t0 WHERE t0.RECORDID = ?" withBindings: 1:"0032274bc94901122623a943007f46"(recordID)>: Next exception:SQL State:42000 -- error code: 937 -- msg: ORA-00937: not a single-group group function This is the code that we use to add the temporary attribute. public static Number aggregateNumberFunctionWithQualifier(EOEditingContext ec, String entityName, String attributeName, String function, EOQualifierqualifier) { EOEntity entity = EOUtilities.entityNamed(ec,entityName); NSArray results = null; EOAttributeattribute = createAggregateAttribute(ec, function, attributeName,entityName, "java.lang.Number", "i"); EOQualifier schemaBasedQualifier = entity.schemaBasedQualifier(qualifier); EOFetchSpecification fs = new EOFetchSpecification(entityName, schemaBasedQualifier, null); synchronized (entity) { entity.addAttribute(attribute); try{ fs.setFetchesRawRows(true); fs.setRawRowKeyPaths(new NSArray(attribute.name())); results = ec .objectsWithFetchSpecification (fs ); }finally { entity .removeAttribute(attribute); } } if ((results != null) && (results.count() == 1)) { NSDictionary row = (NSDictionary) results.lastObject(); if (row.objectForKey(attribute.name()) != null && row.objectForKey(attribute.name()) instanceof Number) { return (Number) row.objectForKey(attribute.name()); } } return null; } Dov Rosenberg _______________________________________________ Do not post admin requests to the list. They will be ignored.Webobjects-dev mailing list (Webobjects- [EMAIL PROTECTED])Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/mschrag%40mdimensio n . com This email sent to [EMAIL PROTECTED]_______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/drosenberg%40inquira .c om This email sent to [EMAIL PROTECTED]_______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/chill%40global-villag e . net This email sent to [EMAIL PROTECTED]
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