Actually that second statement I made about dump and restore to change table-space location of a table's data might be wrong ... maybe a simple ALTER TABLE <table> ENGINE = InnoDB on an existing InnoDB table might be enough to recreate the table in its own file if you changed the table-space settings. I have not tried it. In any case, it is not related to the topic of discussion.... moving on.....
The conversion to InnoDB is simple. I added a trivial "use at your own risk" script, that I have used many times without problems, to the repo on github: https://github.com/kierankelleher/gic-mysql-tools/blob/master/UtilityScripts/AlterTablesToInnodbEngine.sh I strongly advise you to configure InnoDB settings in /etc/my.cnf before you convert though: https://github.com/kierankelleher/gic-mysql-tools/blob/master/README.markdown After conversion, then you can "hunt for" and "clean up" data integrity issues since conversion to InnoDB will only prevent future issues related to absence of transaction support - it will not fix the data problems created in the past in your database caused by your use of MyISAM. You must find those data problems and manually fix them in SQL to restore the integrity of your database(s) after the conversion. On May 18, 2013, at 11:53 AM, Kieran Kelleher <kelleh...@gmail.com> wrote: > No need to dump and restore. That is only useful to change all InnoDB tables > from a single table-space file to a file per table for example. > > Regards, Kieran. > (Sent from my iPhone) > > > On May 18, 2013, at 7:45 AM, Amedeo Mantica <amedeomant...@me.com> wrote: > >> Sometimes I did that change too. Seems to work but really don't know it is >> the best way. Kieran was suggesting a dump and restore. >> >> Amedeo >> >> Sent from my iPhone >> >> On 18/mag/2013, at 13:10, Mark Gowdy <go...@mac.com> wrote: >> >>> Using SequalPro, it lets me change the table type (in the Table Info tab). >>> This issues the statement: >>> ALTER TABLE `EO_PK_TABLE` ENGINE = InnoDB; >>> >>> Is there any likely downside to this, compared with recreating the schema >>> from scratch? >>> >>> Mark >>> >>> >>> >>> On 17 May 2013, at 23:26, Kieran Kelleher wrote: >>> >>>> InnoDB is all or nothing ..... don't waste your time mixing InnoDB and >>>> MyISAM in transactions - makes the results even more confusing. >>>> >>>> Convert them all..... evidently, InnoDB is faster nowadays anyway. innoDB >>>> can cache everything in memory. MyISAM IIRC only can cache PKs in memory >>>> and must always get rows from disk. There is no benefit to staying on >>>> MyISAM format. >>>> >>>> >>>> On May 17, 2013, at 4:36 PM, Mark Gowdy <go...@mac.com> wrote: >>>> >>>>> Thanks Paul, it looks like you are correct. >>>>> >>>>> Two 'Kieran Kelleher' email stated: >>>>> >>>>>> There is also no row locking on EO_PK_TABLE with myisam, so you will get >>>>>> primary key clashes and subsequent failed inserts if the db is >>>>>> sufficiently contended. >>>>> >>>>> >>>>> and >>>>> >>>>>> (1) Never use MyISAM - no transactional support means a failed >>>>>> editingContext.saveChanges() will not result in a rollback and >>>>>> semi-saved changes to the database..... data integrity goes out the >>>>>> window. Use InnoDB .... don't just convert live DB though, dump/import >>>>>> to a standby server, configure InnoDB first completely and actually do a >>>>>> little bit of studying the MySQL docs to understand how. Also, get a >>>>>> head start here: https://github.com/kierankelleher/gic-mysql-tools >>>>>> >>>>>> (2) Don't create "real" foreign key constraints because MySQL does not >>>>>> support deferred constraints (which is the biggest negative of using >>>>>> MySQL). Instead just manually create indexes on every foreign key field. >>>>>> Otherwise your performance will deteriorate as tables sizes get larger. >>>>> >>>>> Seems like sound advise. >>>>> I now have some careful un-picking to do. >>>>> >>>>> Also, incase anyone is interested, I eventually found the primary key >>>>> generation code in JDBCPlugIn.class : newPrimaryKeys(int count, EOEntity >>>>> entity, JDBCChannel channel) >>>>> Other DB plugins do their own thing, but the MySQL one appears to fall >>>>> back on JDBCPlugIn. >>>>> >>>>> Thanks again, >>>>> >>>>> Mark >>>>> >>>>> >>>>> On 17 May 2013, at 21:18, Paul Yu wrote: >>>>> >>>>>> Well you certainly should not use MyIsam system. Innodb is the right >>>>>> answer. See Kieran's post on this subject. >>>>>> >>>>>> But I'm not sure that will be the end of your issues. >>>>>> >>>>>> Sent from my iPad >>>>>> >>>>>> On May 17, 2013, at 4:03 PM, Mark Gowdy <go...@mac.com> wrote: >>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> We have started getting more of these errors recently, now that the >>>>>>> system is under more load. >>>>>>> >>>>>>> ---- >>>>>>> EvaluateExpression failed: >>>>>>> <com.webobjects.jdbcadaptor._MySQLPlugIn$MySQLExpression: "INSERT INTO >>>>>>> queue_item(ITEM_DATE, ... etc....) >>>>>>> Duplicate entry '4183884' for key 'PRIMARY' >>>>>>> ---- >>>>>>> >>>>>>> I believe the problem is due to the fact that there is more than one >>>>>>> instance trying to write to the 'queue_item' table, and the EO_PK_TABLE >>>>>>> mechanism is handing out the same ID more than once. >>>>>>> Probably something to do with locking. >>>>>>> >>>>>>> Our Database is MySQL 5, and the EO_PK_TABLE is of type MyISAM. >>>>>>> >>>>>>> I tried to find the mechanism that allocate the primary key, but I keep >>>>>>> bumping up against: >>>>>>> >>>>>>> EOAdaptorChannel: >>>>>>> @Deprecated >>>>>>> public NSDictionary<String, Object> >>>>>>> primaryKeyForNewRowWithEntity(EOEntity entity){ >>>>>>> return null; >>>>>>> } >>>>>>> >>>>>>> >>>>>>> Any advise would be appreciated, >>>>>>> >>>>>>> Thanks, >>>>>>> >>>>>>> Mark >>>>>>> >>>>>>> _______________________________________________ >>>>>>> Do not post admin requests to the list. 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