The SQL apply lag on a logical standby database can be caused by several factors:
* A: An undersized undo tablespace can lead to delays in SQL apply operations as it may not be able to handle the volume of undo records generated by the SQL apply process.
* B: SQL apply operations that do full table scans can consume significant system resources, potentially leading to higher apply lag.
* C: An increased number of bulk updates on the primary database may generate a large volume of redo data, which can cause apply lag if the logical standby cannot apply the changes quickly enough.
* F: An undersized shared pool may affect the parsing and execution of SQL statements by SQL apply, which can contribute to the apply lag.
Option D is less likely to be a direct cause of SQL apply lag compared to bulk updates, as inserts generate new data rather than modifying existing data, which SQL apply can typically handle more efficiently.
Option E is incorrect because the size of the standby redo log files on the primary database impacts redo transport lag, not SQL apply lag.
References: Oracle Database High Availability Overview and Oracle Data Guard Concepts and Administration guide provide insights into the factors affecting SQL apply performance on logical standby databases.