PRB: dbopen() Execution Time Degrades

ID: Q70953

The information in this article applies to:

Microsoft SQL Server for OS/2, version 4.2

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 query words: Programming tools dblib Platforms LAN Manager


Keywords          : kbprg SSrvDB_Lib SSrvProg 
Version           : 4.2
Platform          : OS/2 
Issue type        :

Last Reviewed: March 11, 1999