SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Enhancing SQLMX Database Performance

HP NonStop SQL/MX Installation and Management Guide—523723-004

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Matching Block Split Operation to Table Usage

In a table with key-sequenced organization, when an INSERT operation causes a data

block to overflow, the disk process makes room for the new row by splitting the block

and transferring some of its contents to a newly allocated block.

The disk process can use one of two methods to split a block:

•

Split the block in the middle.

•

Split the block at the insertion point when rows are being inserted in sequence and

the user has specified the SEQUENTIAL BLOCKSPLIT ON option of the

CONTROL TABLE statement.

The SEQUENTIAL BLOCKSPLIT ON option can increase the average number of rows

stored per block in certain applications where the disk process cannot detect

sequential insertion of rows.

For detailed information about the CONTROL TABLE statement, including the

SEQUENTIAL BLOCKSPLIT option, see the SQL/MX Reference Manual.