Sybase 12.4.2 - Manual (Page 449)

CHAPTER 12 Managing System Resources
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3 Make sure all users are disconnected from the database, and stop the
database.
• If the -ga command-line switch is set, the database shuts down
automatically after the last user disconnects.
• If -ga is not set, stop the database, by using the stop_asiq utility on
UNIX, or by clicking Shutdown on the database server display on
Windows NT.
4 Restart the database. The new cache sizes are now in effect.
Note It is important to have an appropriate PUBLIC setting of the cache size
options. Otherwise, when the database server is restarted they will revert to the
default settings, which are far too low for most applications.
Setting buffer cache size server switches
Normally you change the buffer cache sizes by setting the
MAIN_CACHE_MEMORY_MB and TEMP_CACHE_MEMORY_MB database
options. However, if you set these parameters to a value that is higher than your
system will accommodate, you will not be able to open the database. If this
occurs, use the server startup options
-iqmc and -iqtc to change the current
buffer cache sizes. These parameters only remain in effect while the server is
running, so you still need to set the buffer cache size database options.
Specifying page size
When you create a database, you set its page size. This parameter, in
conjunction with the size of the buffer cache, determines memory use and disk
I/O throughput for that database.
Setting the page size
Adaptive Server IQ swaps data in and out of memory in units of pages. When
you create a database, you specify a separate page size for the Catalog Store
and the IQ Store. The Temporary Store has the same page size as the IQ Store.
For IQ page size recommendations for the best performance, see “Choosing an
IQ page size” on page 111.