[GitHub] [rocketmq] qsrg commented on issue #3388: HA may not avaiable when slave's commitLog not match master

[GitBox <gi...@apache.org>]

qsrg commented on issue #3388:
URL: https://github.com/apache/rocketmq/issues/3388#issuecomment-929833299


   Before start up the slave，check the commigLog data is correctly by manual is inconvenient to execute 。From the machine of slave broke down to it repaired，we did not modify the data in the store directory of slave，this mistake maybe due to the deletion policy or  other reasons.
   
   add the following checks when master  received slaveRequestOffset at first，if slaveRequestOffset>maxOffset or slaveRequestOffset<minOffset,send last commitLog file. And change slave's dispatchReadRequest method to handle a correct offset from master.
   Is this idea appropriate?
   
   ```
   if (-1 == this.nextTransferFromWhere) {
                           if (0 == HAConnection.this.slaveRequestOffset) {
                               long masterOffset = HAConnection.this.haService.getDefaultMessageStore().getCommitLog().getMaxOffset();
                               masterOffset =
                                   masterOffset
                                       - (masterOffset % HAConnection.this.haService.getDefaultMessageStore().getMessageStoreConfig()
                                       .getMapedFileSizeCommitLog());
   
                               if (masterOffset < 0) {
                                   masterOffset = 0;
                               }
                               this.nextTransferFromWhere = masterOffset;
                           } else {
                              //changes
                               long maxOffset = HAConnection.this.haService.getDefaultMessageStore().getCommitLog().getMaxOffset();
                               long minOffset = HAConnection.this.haService.getDefaultMessageStore().getCommitLog().getMinOffset();
                               if (HAConnection.this.slaveRequestOffset> maxOffset || HAConnection.this.slaveRequestOffset< minOffset) {
                                   long masterOffset =
                                           maxOffset
                                                   - (maxOffset % HAConnection.this.haService.getDefaultMessageStore().getMessageStoreConfig()
                                                   .getMapedFileSizeCommitLog());
   
                                   if (masterOffset < 0) {
                                       masterOffset = 0;
                                   }
                                   this.nextTransferFromWhere = masterOffset;
   
                               }else {
                                   this.nextTransferFromWhere = HAConnection.this.slaveRequestOffset;
                               }
   
                           }
   
                           log.info("master transfer data from " + this.nextTransferFromWhere + " to slave[" + HAConnection.this.clientAddr
                               + "], and slave request " + HAConnection.this.slaveRequestOffset);
                       }
   ```
   


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