PRB: dbopen() Execution Time Degrades

ID Number: Q70953

1.10 1.11 4.20

OS/2

Summary:

SYMPTOMS

When you run an OS/2 multithreaded DB-LIBRARY (db-lib)

application that opens multiple dbprocesses (dbprocs), the

time taken for a dbopen() call to succeed seems to increase

as the number of open dbprocs increases.

CAUSE

The overhead incurred by db-lib and LAN Manager increases as you

open more dbprocs per process. Db-lib allocates memory from the

heap for each open dbproc; as the heap fills up, it takes

longer to find an empty slot. LAN Manager also manages named pipes

by maintaining data structures that increase overhead and

processing time. In addition, all existing heap memory is

eventually used and db-lib might call the operating system to

allocate more space for the heap. This could take from 600

milliseconds to several seconds, depending on how much system

memory is being used.

Additional reference words: Programming tools dblib Platforms LAN Manager