Troubleshooting resources for shadow tables

Checking whether a query was routed to shadow tables by using monitoring interfaces
Use monitoring table functions to view details on which tables were used in the query plan for statements that are in cached memory. You can use monitoring functions to identify the objects that are used in a query plan or to identify the list of statements that are currently cached in memory. By viewing the list of objects and statements, you can check whether a query was routed to a shadow table. If the statement is no longer cached in memory, you must use the EXPLAIN utility.

Checking whether query routing is enabled by using EXPLAIN diagnostics
Use the EXPLAIN utility to generate extended diagnostic information if a statement is no longer cached in memory or you need more detailed query-routing information.

Checking DB2 special register settings
The settings of the CURRENT REFRESH AGE and CURRENT MAINTAINED TABLE TYPES special registers can affect whether shadow tables are considered for query optimization. You must also set the query optimization level to 2 or a value that is greater than or equal to 5.

Checking current latency status
Shadow tables might not be used in the query plan for a statement when latency is out of date.

Checking IBM InfoSphere Change Data Capture replication status
Queries might not be routed to shadow tables if InfoSphere CDC replication stops.

Diagnosing problems with IBM InfoSphere Change Data Capture replication
Errors that are encountered during replication are reported in the IBM InfoSphere Change Data Capture event logs.

Checking the values of IBM InfoSphere Change Data Capture system parameters
Verify that InfoSphere CDC system parameters are set to appropriate values so that query plans can use shadow tables