Merge pull request #3837 from ClickHouse/mysql-binlog-faq

mysql clickpipe: binlog faq

Author: Blargian

docs/integrations/data-ingestion/clickpipes/mysql/faq.md

@@ -9,10 +9,15 @@ title: 'ClickPipes for MySQL FAQ'
 # ClickPipes for MySQL FAQ
 
 ### Does the MySQL ClickPipe support MariaDB?  {#does-the-clickpipe-support-mariadb}
-Yes, the MySQL ClickPipe supports MariaDB 10.0 and above. The configuration for it is very similar to MySQL, with the GTID behaviour being enabled by default.
+Yes, the MySQL ClickPipe supports MariaDB 10.0 and above. The configuration for it is very similar to MySQL, using GTID replication by default.
 
-### Does the MySQL ClickPipe support Planetscale, Vitess? {#does-the-clickpipe-support-planetscale-vitess}
-Currently, we support only standard MySQL. Since PlanetScale is built on Vitess, integrating with Vitess's VStream API and handling VGtids (Vitess Global Transaction IDs) to track incremental changes is required. This differs from how CDC operates in native MySQL. Adding support for this functionality is being actively worked on.
+### Does the MySQL ClickPipe support PlanetScale, Vitess, or TiDB? {#does-the-clickpipe-support-planetscale-vitess}
+No, these do not support MySQL's binlog API.
+
+### How is replication managed? {#how-is-replication-managed}
+We support both `GTID` & `FilePos` replication. Unlike Postgres there is no slot to manage offset. Instead, you must configure your MySQL server to have a sufficient binlog retention period. If our offset into the binlog becomes invalidated *(eg, mirror paused too long, or database failover occurs while using `FilePos` replication)* then you will need to resync the pipe. Make sure to optimize materialized views depending on destination tables, as inefficient queries can slow down ingestion to fall behind the retention period.
+
+It's also possible for an inactive database to rotate the log file without allowing ClickPipes to progress to a more recent offset. You may need to setup a heartbeat table with regularly scheduled updates.
 
 ### Why am I getting a TLS certificate validation error when connecting to MySQL? {#tls-certificate-validation-error}
 If you see an error like `failed to verify certificate: x509: certificate is not valid for any names`, this occurs when the SSL/TLS certificate on your MySQL server doesn't include the connecting hostname (e.g., EC2 instance DNS name) in its list of valid names. ClickPipes enables TLS by default to provide secure encrypted connections.