Each configured data cache on the server has this block of information in the configuration file:
[Named Cache:cache_name]
cache size = {size | DEFAULT}
cache status = {mixed cache | log only | default data cache}
cache replacement policy = {DEFAULT |
relaxed LRU replacement| strict LRU replacement }
Size units can be specified with:
P – pages (Adaptive Server pages)
K – kilobytes (default)
M – megabytes
G – gigabytes
This example shows the configuration file entry for the default data cache:
[Named Cache:default data cache] cache size = DEFAULT cache status = default data cache cache replacement policy = strict LRU replacement
The default data cache entry is the only cache entry that is required in for Adaptive Server to start. It must have the cache size and cache status, and the status must be “default data cache.”
If the cache has pools configured in addition to the pool, the block in the preceding example is followed by a block of information for each pool:
[16K I/O Buffer Pool] pool size = size wash size = size local async prefetch limit = DEFAULT
In some cases, there is no configuration file entry
for the pool in a cache. If you change the asynchronous prefetch
percentage with sp_poolconfig, the change
is not written to the configuration file, only to system tables.
This example shows output from sp_cacheconfig, followed by the configuration file entries that match this cache and pool configuration:
Cache Name Status Type Config Value Run Value ------------------------ --------- -------- ------------ ------------ default data cache Active Default 29.28 Mb 25.00 Mb pubs_cache Active Mixed 20.00 Mb 20.00 Mb pubs_log Active Log Only 6.00 Mb 6.00 Mb tempdb_cache Active Mixed 4.00 Mb 4.00 Mb ------------ ------------ Total 59.28 Mb 55.00 Mb ======================================================================= Cache: default data cache, Status: Active, Type: Default Config Size: 29.28 Mb, Run Size: 29.28 Mb Config Replacement: strict LRU, Run Replacement: strict LRU Config Partition: 1, Run Partition: 1 IO Size Wash Size Config Size Run Size APF Percent -------- --------- ------------ ------------ ----------- 2 Kb 3844 Kb 6.50 Mb 25.28 Mb 10 4 Kb 512 Kb 4.00 Mb 4.00 Mb 10 ======================================================================= Cache: pubs_cache, Status: Active, Type: Mixed Config Size: 20.00 Mb, Run Size: 20.00 Mb Config Replacement: strict LRU, Run Replacement: strict LRU Config Partition: 1, Run Partition: 1 IO Size Wash Size Config Size Run Size APF Percent -------- --------- ------------ ------------ ----------- 2 Kb 2662 Kb 0.00 Mb 13.00 Mb 10 16 Kb 1424 Kb 7.00 Mb 7.00 Mb 10 ======================================================================= Cache: pubs_log, Status: Active, Type: Log Only Config Size: 6.00 Mb, Run Size: 6.00 Mb Config Replacement: relaxed LRU, Run Replacement: relaxed LRU Config Partition: 1, Run Partition: 1 IO Size Wash Size Config Size Run Size APF Percent -------- --------- ------------ ------------ ----------- 2 Kb 716 Kb 0.00 Mb 1.00 Mb 10 4 Kb 1024 Kb 5.00 Mb 5.00 Mb 10 ======================================================================= Cache: tempdb_cache, Status: Active, Type: Mixed Config Size: 4.00 Mb, Run Size: 4.00 Mb Config Replacement: strict LRU, Run Replacement: strict LRU Config Partition: 1, Run Partition: 1 IO Size Wash Size Config Size Run Size APF Percent -------- --------- ------------ ------------ ----------- 2 Kb 818 Kb 0.00 Mb 4.00 Mb 10
This is the matching configuration file information:
[Named Cache:default data cache] cache size = 29.28M cache status = default data cache cache replacement policy = DEFAULT local cache partition number = DEFAULT [2K I/O Buffer Pool] pool size = 6656.0000k wash size = 3844 K local async prefetch limit = DEFAULT [4K I/O Buffer Pool] pool size = 4.0000M wash size = DEFAULT local async prefetch limit = DEFAULT [Named Cache:pubs_cache] cache size = 20M cache status = mixed cache cache replacement policy = strict LRU replacement local cache partition number = DEFAULT [16K I/O Buffer Pool] pool size = 7.0000M wash size = DEFAULT local async prefetch limit = DEFAULT [Named Cache:pubs_log] cache size = 6M cache status = log only cache replacement policy = relaxed LRU replacement local cache partition number = DEFAULT [4K I/O Buffer Pool] pool size = 5.0000M wash size = DEFAULT local async prefetch limit = DEFAULT [Named Cache:tempdb_cache] cache size = 4M cache status = mixed cache cache replacement policy = DEFAULT local cache partition number = DEFAULT
For more information about the configuration file, see Chapter 5, “Setting Configuration Parameters.”
WARNING! Check the max memory configuration parameter and allow enough memory for other Adaptive Server needs. If you assign too much memory to data caches in your configuration file, Adaptive Server does not start. If this occurs, edit the configuration file to reduce the amount of space in the data caches, or increase the max memory allocated to Adaptive Server. see Chapter 5, “Setting Configuration Parameters,” for suggestions on monitoring cache sizes.
