Opening this idea on behalf of a customer.
It seems Qlik Replicate is doing a LOB lookup instead of reading from the binlogs of RDS for MySQL source instances when working with "limited LOB size" settings. The binlog of MySQL stores the LOBs as seen in the below page. There is a possibility of improving the performance of Replication if Qlik Replicate can read the LOB data directly from the log rather than always doing a LOB lookup.
For Internal reference: case 00055009
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https://dev.mysql.com/doc/refman/5.7/en/replication-options-binary-log.html#sysvar_binlog_row_image
You can cause the server to log full or minimal rows using the binlog_row_image system variable. This variable actually takes one of three possible values, as shown in the following list:
- full: Log all columns in both the before image and the after image.
- minimal: Log only those columns in the before image that are required to identify the row to be changed; log only those columns in the after image where a value was specified by the SQL statement, or generated by auto-increment.
- noblob: Log all columns (same as full), except for BLOB and TEXT columns that are not required to identify rows, or that have not changed.
The default value is full.
