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Binlog_cache_disk_use  status variables can be useful for tuning the size of this variable. See Section 5.4.4, “The Binary Log” . 

binlog_cache_size  sets the size for the transaction cache only; the size of the statement cache is governed by the binlog_stmt_cache_size  system variable. 

• binlog_checksum 

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When enabled, this variable causes the source to write a checksum for each event in the binary log. binlog_checksum  supports the values NONE  (which disables checksums) and CRC32 . The default is CRC32 . When binlog_checksum  is disabled (value NONE ), the server verifies that it is writing only complete events to the binary log by writing and checking the event length (rather than a checksum) for each event. 

Setting this variable on the source to a value unrecognized by the replica causes the replica to set its own binlog_checksum  value to NONE , and to stop replication with an error. If backward compatibility with older replicas is a concern, you may want to set the value explicitly to NONE . 

Up to and including MySQL 8.0.20, Group Replication cannot make use of checksums and does not support their presence in the binary log, so you must set binlog_checksum=NONE  when configuring a server instance to become a group member. From MySQL 8.0.21, Group Replication supports checksums, so group members may use the default setting. 

Changing the value of binlog_checksum  causes the binary log to be rotated, because checksums must be written for an entire binary log file, and never for only part of one. You cannot change the value of binlog_checksum  within a transaction. 

When binary log transaction compression is enabled using the binlog_transaction_compression system variable, checksums are not written for individual events in a compressed transaction payload. Instead a checksum is written for the GTID event, and a checksum for the compressed Transaction_payload_event . 

• binlog_direct_non_transactional_updates 

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