Performance Engineering Interview Questions #10

Following are the Performance Engineering Interview Questions Set #10.

Q. 46 What is a Large Pool in Oracle DB?

Ans: The large pool is an optional memory area intended for memory allocations that are larger than is appropriate for the shared pool. It can provide large memory allocations for the following:

UGA for the shared server
Message buffers used in parallel execution
Buffers for Recovery Manager (RMAN) I/O slaves
Buffers for deferred inserts

Q. 47 What is Java Pool in Oracle DB?

Ans: It stores all session-specific Java code and data within the Java Virtual Machine (JVM). This memory includes Java objects that are migrated to the Java session space at end-of-call.

Q. 48 What is a Private SQL Pool?

Ans: A private SQL area holds information about a parsed SQL statement and other session-specific information for processing. When a server process executes SQL or PL/SQL code, the process uses the private SQL area to store bind variable values, query execution state information, and query execution work areas.

Note: A private SQL area, which is in the PGA, is different from the shared SQL area, which stores execution plans in the SGA.

Q. 49 What is an In-Memory Column Store?

Ans: The In-Memory Area is an optional SGA component that contains the In-Memory Column Store (IM column store). The IM column store contains copies of tables, partitions, and materialized views in a columnar format optimized for rapid scans. The IM column store supplements the database buffer cache, which stores data in traditional row format.

Q. 50 What is a Stream Pool in Oracle DB?

Ans: The Streams pool provides memory for Oracle Advanced Queuing (AQ) and replication processes. The stream pool stores LCRs captured by a capture process and other messages that are enqueued into a buffered queue.