Merge pull request #805 from knepe/update-rds-docs

Update rds docs

Author: Shlomi Noach

doc/rds.md

@@ -26,6 +26,14 @@ If you use `pt-table-checksum` as a part of your data integrity checks, you migh
 This tool requires binlog_format=STATEMENT, but the current binlog_format is set to ROW and an error occurred while attempting to change it.  If running MySQL 5.1.29 or newer, setting binlog_format requires the SUPER privilege.  You will need to manually set binlog_format to 'STATEMENT' before running this tool.
 ```
 
+#### Binlog filtering
+
+In Aurora, the [binlog filtering feature][aws_replication_docs_bin_log_filtering] is enabled by default. This becomes an issue when gh-ost tries to do the cut-over, because gh-ost waits for an entry in the binlog to proceed but this entry will never end up in the binlog because it gets filtered out by the binlog filtering feature.  
+You need to turn this feature off during the migration process.  
+Set the `aurora_enable_repl_bin_log_filtering` parameter to 0 in the Parameter Group for your cluster.  
+When the migration is done, set it back to 1 (default).
+
+
 #### Preflight checklist
 
 Before trying to run any `gh-ost` migrations you will want to confirm the following:
@@ -35,6 +43,7 @@ Before trying to run any `gh-ost` migrations you will want to confirm the follow
 - [ ] Executing `SHOW SLAVE STATUS\G` on your replica cluster displays the correct master host, binlog position, etc.
 - [ ] Database backup retention is greater than 1 day to enable binlogs
 - [ ] You have setup [`hooks`][ghost_hooks] to issue RDS procedures for stopping and starting replication. (see [github/gh-ost#163][ghost_rds_issue_tracking] for examples)
+- [ ] The parameter `aurora_enable_repl_bin_log_filtering` is set to 0
 
 [new_issue]: https://github.com/github/gh-ost/issues/new
 [assume_rbr_docs]: https://github.com/github/gh-ost/blob/master/doc/command-line-flags.md#assume-rbr
@@ -43,3 +52,4 @@ Before trying to run any `gh-ost` migrations you will want to confirm the follow
 [percona_toolkit_patch]: https://github.com/jacobbednarz/percona-toolkit/commit/0271ba6a094da446a5e5bb8d99b5c26f1777f2b9
 [ghost_hooks]: https://github.com/github/gh-ost/blob/master/doc/hooks.md
 [ghost_rds_issue_tracking]: https://github.com/github/gh-ost/issues/163
+[aws_replication_docs_bin_log_filtering]: https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Replication.html#AuroraMySQL.Replication.Performance