tag:blogger.com,1999:blog-768233104244702633.post972844931858656963..comments2023-11-16T03:16:54.746-08:00Comments on The Scale-Out Blog: MySQL 5.0 to 4.1 "Down-Version" Replication using TungstenRobert Hodgeshttp://www.blogger.com/profile/05379726998057344092noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-768233104244702633.post-62823272794268960922008-09-14T18:23:00.000-07:002008-09-14T18:23:00.000-07:00Hi Linas! On #1, that's correct that you have to ...Hi Linas! <BR/><BR/>On #1, that's correct that you have to ensure you use appropriate commands to replicate. DDL commands are especially delicate. We should add a filter mechanism ASAP that allows users to drop or morph replication events easily. <BR/><BR/>On #2, no, I think even statement events will still be useful. Basic insert/update/deletes are pretty fungible at the syntax level so they work across versions. The main issue is what happens when you have to change them to make changes backwards compatible for old schema. In that case it's easier if the replication events are Tuple events containing raw data. We plan to add these shortly. <BR/><BR/>(Full disclosure: Linas works at Continuent and sent these questions via email. I asked him to post them on the blog because they are of general interest.)Robert Hodgeshttps://www.blogger.com/profile/05379726998057344092noreply@blogger.comtag:blogger.com,1999:blog-768233104244702633.post-74636998085997894572008-09-14T01:47:00.000-07:002008-09-14T01:47:00.000-07:00Hello Robert,I just read your new blog comment. I ...Hello Robert,<BR/><BR/>I just read your new blog comment. I would like to comment and ask some questions about it:<BR/>1. I understand that Tungsten Replicator is replicating SQL statements currently. That’s why this down-version replication would only work until we do not use any lower-MySQL-version-not-supported SQL statements. Eg. If a client would be issuing the CREATE SCHEMA on a master, it would fail on the slave. Is this correct?<BR/>2. Some time ago I had experience with a big migration from MySQL 4 to MySQL 5. We had a lot of SQL statement changes to do in a web app to get it working on MySQL 5. The company's data was critical (financial) so at that moment we would have really used down-version replication if it would have been available. Do I understand correctly, that for a case like that, Tungsten Replicator _will_ be useful, but only when it will have row replication instead of currently available SQL statement replication?<BR/><BR/>Thank you,<BR/>Linas VirbalasLinas Virbalashttps://www.blogger.com/profile/18254506169133583586noreply@blogger.com