Informix Guide to SQL: Tutorial
Chapter 7: Programming for a Multiuser Environment
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Locking and Performance
Because a lock serializes access to one piece of data, it reduces concurrency; any other programs that want access to that data must wait. The database server can place a lock on a single row, a disk page (which holds multiple rows), a whole table, or an entire database. The more locks it places and the larger the objects it locks, the more concurrency is reduced. The fewer the locks and the smaller the locked objects, the greater concurrency and performance can be.
This section discusses how a program can achieve the following goals:
To place all the locks needed to ensure data integrity
To lock the fewest, smallest pieces of data possible consistent with the preceding goal
Informix Guide to SQL: Tutorial
, version 9.1
Copyright © 1998, Informix Software, Inc. All rights reserved.
