{"issue":{"state":"closed","created_at":"2011-10-06T20:12:20Z","updated_at":"2011-12-15T02:19:51Z","user":{"gravatar_id":"8aa6dad26475f295e7786e03329a506f","id":593676,"url":"https://api.github.com/users/seattlegaucho","avatar_url":"https://secure.gravatar.com/avatar/8aa6dad26475f295e7786e03329a506f?d=https://a248.e.akamai.net/assets.github.com%2Fimages%2Fgravatars%2Fgravatar-140.png","login":"seattlegaucho"},"comments":10,"body":"Hi there, me again.\r\n\r\nI'd like to know if it would be possible to add an option to avoid running the CHANGE MASTER TO sequence on the promoted slave. We have some master-master use cases where it is desirable to be able to resume replication once the failed master comes back online.\r\n\r\nWe have this setup ( A <-> B, A -> C & B -> D):\r\n\r\n```\r\n+----+            +----+\r\n|  A |  < --- >   |  B |\r\n+----+            +----+\r\n   V                 V\r\n+----+            +----+\r\n|  C |            |  D |\r\n+----+            +----+\r\n```\r\n\r\nWhich upon failure would become (A -> C, A -> D and B is offline):\r\n\r\n```\r\n+----+          +----+\r\n|  A |          |  X |\r\n+----+          +----+\r\n   V        \\  \r\n+----+          +----+\r\n|  C |          |  D |\r\n+----+          +----+\r\n```\r\n\r\nWhat we'd like to do, when possible, as we bring B back online is: (A <-> B, A -> C & A -> D) \r\n\r\n```\r\n+----+            +----+\r\n|  A |  < --- >   |  B |\r\n+----+            +----+\r\n   V        \\  \r\n+----+          +----+\r\n|  C |          |  D |\r\n+----+          +----+\r\n```\r\n\r\nRight now we can replicate from A -> B, but we need to do a full CHANGE MASTER TO ... on A to start replication back from B. I'd like to be able to add an option to the MHA config file, so that step is not needed. The option should be OFF by default.\r\n\r\nThanks for your efforts on the project.\r\n\r\nGerry\r\nI hope the ASCII art helps to understand what I'm trying to do.\r\n\r\nCheers,\r\nG","assignee":null,"id":1837349,"number":15,"pull_request":{"patch_url":null,"html_url":null,"diff_url":null},"labels":[],"title":"Feature Request: Option to avoid running CHANGE MASTER TO on the promoted slave","html_url":"https://github.com/yoshinorim/mha4mysql-manager/issues/15","closed_at":"2011-11-07T10:11:46Z","milestone":null,"url":"https://api.github.com/repos/yoshinorim/mha4mysql-manager/issues/15"},"action":"created","comment":{"created_at":"2011-12-15T02:19:51Z","updated_at":"2011-12-15T02:19:51Z","user":{"gravatar_id":"3606cab98a9cd9a27885a1f922b7ff7a","id":253614,"url":"https://api.github.com/users/yoshinorim","avatar_url":"https://secure.gravatar.com/avatar/3606cab98a9cd9a27885a1f922b7ff7a?d=https://a248.e.akamai.net/assets.github.com%2Fimages%2Fgravatars%2Fgravatar-140.png","login":"yoshinorim"},"body":"MHA checks master's binary log name and end log pos written in relay logs. MHA uses master's binary log name and end log pos as a global transaction id. All slaves should have consistent information about master's binary log name and end log pos, so as long as you don't update slaves (or don't execute replication-unsafe queries on master) no conflicts will happen. In depth algorithm is described here: http://www.slideshare.net/matsunobu/automated-master-failover  (though it's a bit old). ","id":3155759,"url":"https://api.github.com/repos/yoshinorim/mha4mysql-manager/issues/comments/3155759"}}