When Sybase Replication Agent truncates its transaction log in the primary database, it updates its internal statistics counters. The statistics update process entails querying transaction log objects in the primary database. Because these query operations consume system resources, they can have an adverse affect on primary database performance if they occur frequently in systems with very large or numerous marked tables, or large transaction volume.
To reduce the impact of log truncation statistics update queries, the Replication Agent for Informix provides two parameters that allow you to control the level of the statistics update queries and how often they run:
pdb_update_stats_count – defines the cumulative number of rows that must be truncated from the log before running the statistics update queries.
pdb_update_stats_type – defines the level of queries to run (low, medium, or high).
These configuration parameters are supported only by
the Replication Agent for Informix. They have no effect with a Replication Agent for
another type of data server.
To set or change the pdb_update_stats_count and pdb_update_stats_type configuration parameters, use the ra_config command. See the Sybase Replication Agent Administration Guide and Reference Manual for more information.
The following sections describe these configuration parameters in detail.
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