sp_cacheconfig

Syntax

sp_cacheconfig [cachename [, "cache_size[P | K | M | G]"] 
	[, logonly | mixed | inmemory_storage][, strict | relaxed]]
	[, "cache_partition=[1 | 2 | 4 | 8 | 16 | 32 | 64]"]
	[, instance instance_name]

Parameters

cachename – is the name of the data cache to be created or configured. Cache names must be unique, and can be up to 30 characters long. A cache name does not have to be a valid SAP ASE identifier, that is, it can contain spaces and other special characters.
cache_size – is the size of the data cache to be created or, if the cache already exists, the new size of the data cache. The minimum size of a cache is 256 times the logical page size of the server. Size units can be specified with P for pages, K for kilobytes, M for megabytes, or G for gigabytes. The default is K. For megabytes and gigabytes, you can specify floating-point values. The cache size is in multiples of the logical page size.
logonly | mixed | inmemory_storage – specifies the type of cache. inmemory_storage indicates you are creating a cache for an in-memory or relaxed-durability database.
strict | relaxed – specifies the cache replacement policy.
cache_partition – specifies the number of partitions to create in the cache.
instance_name – (In cluster environments) Is the name of the instance with a cache that you are adjusting.

Examples

Example 1 – Creates the data cache pub_cache with 10MB of space. All space is in the default logical page size memory pool:
```
sp_cacheconfig pub_cache, "10M"
```
Example 2 – Reports the current configuration of pub_cache and any memory pools in the cache:
```
sp_cacheconfig pub_cache
```
Example 3 – Drops pub_cache at the next start of the SAP ASE server:
```
sp_cacheconfig pub_cache, "0"
```
Example 4 – Creates pub_log_cache and sets its type to logonly in a single step:
```
sp_cacheconfig pub_log_cache, "2000K", logonly
```
Example 5 – The first command creates the cache pub_log_cache with the default type mixed. The second command changes its status to logonly. The resulting configuration is the same as that in example 4:
```
sp_cacheconfig pub_log_cache, "2000K"
sp_cacheconfig pub_log_cache, logonly
```
Example 6 – Creates a cache and sets the size, type, replacement policy and number of cache partitions:
```
sp_cacheconfig 'newcache', '50M', mixed, strict, "cache_partition=2"
```
Example 7 – Creates an in-memory storage named pubs3_imdb:
```
sp_cacheconfig pubs_imdb, '500M', inmemory_storage
```
Example 8 – (In cluster environments) Displays the cache for instance blade1:
```
sp_cacheconfig 'instance blade1'
```
Example 9 – (In cluster environments) Sets the size of the Sales Cache size on blade1 to 100 megabytes:
```
sp_cacheconfig 'Sales Cache', '100M', 'instance blade1'
```
Example 10 – (In cluster environments) Sets the size of the Sales Cache size on blade1 to 0 megabytes, effectively dropping the cache.
```
sp_cacheconfig 'Sales Cache', '0M', 'instance blade1'
```

Usage

The minimum cache size is 256 times the logical page size. For example, a 4K server would have a minimum cache size of 1024K.
If the SAP ASE server is unable to allocate all the memory requested while you are creating a new cache or adding memory to an existing cache, it allocates all the available memory. However, this additional memory is allocated at the next restart of the SAP ASE server.
If there are objects bound to cache (including the default cache), you cannot delete the cache until you unbind the objects.
(In cluster environments) If you do not specify an instance_name, the cache for the cluster is displayed.

Some of the actions you perform with sp_cacheconfig are dynamic (do not require a restart of the SAP ASE server) and some are static (require a reboot). The dynamic and static actions are:

Dynamic sp_cacheconfig Actions	Static sp_cacheconfig Actions
Adding a new cache	Changing the number of cache partitions
Adding memory to an existing cache	Reducing a cache size
Deleting a cache	Changing the replacement policy
Changing a cache type

When you first create a data cache:
- All space is allocated to the logical page size memory pool.
- The default type is mixed.
This figure shows a data cache for a 2K server with two user-defined data caches configured and the following pools:
- The default data cache with a 2K pool and a 16K pool
- A user cache with a 2K pool and a 16K pool
- A log cache with a 2K pool and a 4K pool
  
  Data Cache With Default and User-Defined Caches
The default data cache must always have the type default, and no other cache can have the type default.
The SAP ASE housekeeper task does not do any buffer washing in caches with a type of logonly or in caches with a relaxed LRU replacement policy.

The following commands perform only 2K I/O: disk init, some dbcc commands, and drop table. The dbcc checkdb and dbcc checktable commands can perform large I/O for tables, but perform 2K I/O on indexes. Cache usage for Transact-SQL commands, depending on the binding of the database or object, are:

Command	Database Bound	Table or Index is Bound	Database or Object Not Bound
create index	Bound cache	N/A	Default data cache
disk init	N/A	N/A	Default data cache
dbcc checkdb	Bound cache	N/A	Default data cache
dbcc checktable, indexalloc, tablealloc	Bound cache	Bound cache	Default data cache
drop table	Bound cache	Bound cache	Default data cache

Recovery uses only the logical page size pool of the default data cache. All pages for all transactions that must be rolled back or rolled forward are read into and changed in this pool. Be sure that your default logical page size pool is large enough for these transactions.

When you use sp_cacheconfig with no parameters, it reports information about all of the caches on the server. If you specify only a cache name, it reports information about only the specified cache. If you use a fragment of a cache name, it reports information for all names matching “%fragment%”.

All reports include a block of information that reports information about caches, and a separate block of data for each cache that provides information about the pools within the cache.

The output below, from a server using 2K, shows the configuration for:

The default data cache with two pools: a 2K pool and a 16K pool. The default data cache has 2 partitions.
pubs_cache with two pools: 2K and 16K

pubs_log, with the type set to logonly and cache replacement policy set to relaxed, with a 2K pool and a 4K pool

Cache Name               Status    Type     Config Value  Run Value
 ----------------------- --------- -------- ------------ --------
default data cache        Active   Default      0.00 Mb   26.09 Mb 
pubs_cache               Active    Mixed        10.00 Mb  10.00 Mb 
pubs_log                 Active    Log Only      2.40 Mb    2.40 M
                                              ------------- --------
                                      Total     12.40 Mb   38.49 Mb
===================================================================
Cache: default data cache,   Status: Active,   Type: Default
      Config Size: 0.00 Mb,   Run Size: 26.09 Mb
      Config Replacement: strict LRU,   Run Replacement: strict LRU
      Config Partition:            2,   Run Partition:            2
 IO Size  Wash Size Config Size  Run Size     APF Percent 
 -------- --------- ------------ ------------ ----------- 
     2 Kb   3704 Kb      0.00 Mb     18.09 Mb     10
    16 Kb   1632 Kb      8.00 Mb      8.00 Mb     10
===================================================================
Cache: pubs_cache,   Status: Active,   Type: Mixed
      Config Size: 10.00 Mb,   Run Size: 10.00 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   1228 Kb      0.00 Mb      6.00 Mb     10
    16 Kb    816 Kb      4.00 Mb      4.00 Mb     10
===================================================================
Cache: pubs_log,   Status: Active,   Type: Log Only
      Config Size: 2.40 Mb,   Run Size: 2.40 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    206 Kb      0.00 Mb      1.01 Mb     10
    16 Kb    272 Kb      1.40 Mb      1.39 Mb     10

The meaning of the columns in the output are:

Column	Meaning
Cache Name	The name of the cache.
Status	One of the following: “Active” “Pend/Act” “Pend/Del” The status “Pend” is short for pending. It always occurs in combination with either “Act” for Active or “Del” for Delete. It indicates that a configuration action has taken place, but that the server must be restarted in order for the changes to take effect.
Type	“Mixed” or “Log Only” for user-defined caches, “Default” for the default data cache.
I/O Size	The size of I/O for a memory pool. This column is blank on the line that shows that cache configuration.
Wash Size	The size of the wash area for the pool. As pages enter the wash area of the cache, they are written to disk. This column is blank on the line that shows the cache configuration.
Config Value or Config Size	The size that the cache or pool. If the value is 0, the size has not been explicitly configured, and a default value is used.
Run Value or Run Size	The size of the cache or pool now in use on the SAP ASE server.
Config/ Run Replacement	The cache policy (strict or relaxed) that is used for the cache after the next restart, and the current replacement policy. These differ only if the policy has been changed since the last reboot.
Config/Run Partition	The number of cache partitions that is used for the cache, and the current number of partitions. These differ if sp_cacheconfig has been used to change the number of partitions since the last reboot.
APF Percent	The percentage of buffers in the pool that can hold buffers that have been fetched by asynchronous prefetch, but have not been used.
Total	The total size of data cache, if the report covers all caches, or the current size of the particular cache, if you specify a cache name.

Effects of Restarts and sp_cacheconfig on Cache Status
This figure shows the effects of restarts and sp_cacheconfig on cache status.

You can also configure caches and pools by editing the configuration file. For more information, see the System Administration Guide.

Permissions

The permission checks for sp_cacheconfig differ based on your granular permissions settings.

Setting	Description
Enabled	With granular permissions enabled, you must be a user with `manage data cache` privilege. Any user can execute sp_cacheconfig to view cache configurations
Disabled	With granular permissions disabled, you must be a user with sa_role. Any user can execute sp_cacheconfig to view cache configurations

Auditing

Values in event and extrainfo columns from the sysaudits table are:

Information	Values
Event	38
Audit option	exec_procedure
Command or access audited	Execution of a procedure
Information in `extrainfo`	Roles – Current active roles Keywords or options – NULL Previous value – NULL Current value – NULL Other information – All input parameters Proxy information – Original login name, if set proxy in effect