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What are system bufferpools or hidden bufferpools in DB2?

Technote (FAQ)


Question

What are system bufferpools?

Cause

The System bufferpools are created by DB2 itself for emergency situations and used when the regular bufferpools or bufferpool configured for the database could not be allocated.

Answer

To ensure that an appropriate buffer pool is available in all circumstances, DB2 creates small system buffer pools, one with each of the following page sizes: 4 KB, 8 KB, 16 KB, and 32 KB. The size of each buffer pool is 16 pages. These buffer pools are hidden; they are not in the system catalog or in the buffer pool system files. These could not be used or altered directly.

Usually, these hidden system bufferpools are used when the main bufferpools could not be allocated due to insufficient memory or, other similar situations. These are used to avoid failure of functioning of the DB2 database. But, one should not continue to run a database which failed to allocate the main bufferpools and using the system bufferpools temporarily. Instead, fix the main bufferpool allocation failure reason and start using the normal bufferpools as soon as possible.

The name of the system bufferpools for four different page sizes :

IBMSYSTEMBP4K

IBMSYSTEMBP8K

IBMSYSTEMBP16K

IBMSYSTEMBP32K

Related information

Designing buffer pools
Buffer pool management

Document information

More support for: DB2 for Linux, UNIX and Windows
Database Objects/Config - Bufferpools

Software version: 9.1, 9.5, 9.7, 9.8, 10.1, 10.5

Operating system(s): AIX, HP-UX, Linux, Solaris, Windows

Software edition: Advanced Enterprise Server, Enterprise Server, Express, Workgroup Server

Reference #: 1643819

Modified date: 18 November 2015


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