Sybase 12.4.2 User Manual

Page 448

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Overview of memory use

428

Setting buffer cache size database options

To set buffer cache sizes permanently (that is, until you explicitly reset them)
use the

SET OPTION

statement. Follow the procedure below.

To change the buffer cache sizes permanently:

1

If the database whose cache sizes you are changing is not already started,
start it now:

START DATABASE

dbfile [AS dbname] [ON engine_name]

2

Set one or both cache sizes.

To set the buffer cache size for the IQ Store (the main buffer cache)
use the following syntax:

SET OPTION "PUBLIC".MAIN_CACHE_MEMORY_MB =

#_of_MB

To set the buffer cache size for the Temporary Store (the temp buffer
cache) use the following syntax:

SET OPTION "PUBLIC".TEMP_CACHE_MEMORY_MB =

#_of_MB

-iqmc

and

-iqtc

server

switches

Reset cache sizes when
the database is not
running. Especially useful
if cache sizes are larger
than your system can
accommodate.

From the time the server is
started until it is stopped

“Setting buffer cache
size server switches” on
page 429

-iqsmem

and

-iqwmem

server switches

Use on some UNIX
platforms to provide
additional memory for use
as buffer caches.

From the time the server is
started until it is stopped

“Platform-specific
memory options” on
page 434

LOAD_MEMORY_MB

database option

Indirectly affects buffer
cache size, by controlling
the memory that can be
used for loads. On some
platforms, allowing
unlimited memory for
loads means less memory
is available for buffer
caches.

Immediately until you reset
the option

“Memory for loads,
synchronizations, and
deletions” on page 421

Method

When to use it

How long the setting is
effective

For more
information, see

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