INF: Memory Overhead for Connections, Objects, Locks, and DBs

ID: Q160234

The information in this article applies to:

Microsoft SQL Server versions 6.0, 6.5

SUMMARY

This article describes the memory overhead for the SQL Server configuration settings for user connections, open objects, locks, and open databases.

MORE INFORMATION

SQL Server 6.0:


   Parameter               Value
   ----------------------------------------------------------------
   User connections        44 KB per user (approximately -- see below)
   Locks                   52 bytes per lock
   Open objects           224 bytes per object
   Open databases          20 bytes, plus 160 bytes per database

SQL Server 6.5:


   Parameter               Value
   ---------------------------------------------------------------
   User connections        44 KB per user (approximately -- see below)
   Locks                   60 bytes per lock
   Open objects           240 bytes per object
   Open databases       1,144 bytes, plus 160 bytes per database

User connection overhead is made up of a fixed amount of memory (18 KB) allocated per connection, plus memory allocated to structures supporting the connection within SQL Server and Windows NT Server. This value depends on the number of connections, the number of shared threads, and other structures allocated. Empirical testing has shown that this dynamic overhead is approximately 26 KB per user connection, giving a total of 44 KB per connection. This applies up to the worker thread limit; at this point the connections begin sharing threads, and the overhead per connection is reduced.

Additional query words: usage

Keywords : kbenv kbusage SSrvGen
Version : 6.0 6.5
Platform : WINDOWS
Issue type : kbhowto