Determines whether the Log Transfer Interface component sends all columns in row after images, or only the columns that changed in an update operation.
true – enables minimal column information (only changed columns in row after images) in Log Transfer Language (LTL) for update operations.
false – disables minimal column information in LTL for update operations.
When the column_compression parameter is set to false, the LTI component sends complete row after images in LTL, including columns in which no data changed as a result of an update operation.
When the column_compression parameter is set to true, the LTI component sends minimal column information in the row after images in LTL, with only the columns that changed as a result of an update operation. Columns in which no data changed as a result of the update are not sent in LTL.
In general, setting the value of the column_compression parameter to true provides better Replication Agent throughput.
If your Replication Agent instance is configured to send minimal column data—column_compression and ltl_send_only_primary_keys are set to true—some column data may be omitted for columns that are specified as searchable in a replication definition. Consequently, errors may occur at a subscribing database where data needed for an insert, subscription migration, or custom function string is missing. Sybase therefore recommends that you enable autocorrection for any table referenced in a replication definition with searchable columns.