AUTO_TUNE_SERVER_SIZE configuration parameter

Use the AUTO_TUNE_SERVER_SIZE configuration parameter to set the sizes of memory and storage spaces to allocate based on the number of expected concurrent users.

onconfig.std value
Not in the onconfig.std file.
Default value
Not set.
value if you created a server during installation
Depends on the number of users you specify in the installation program.
values
SMALL = 1 - 100 users
MEDIUM = 101 - 500 users
LARGE = 501 - 1000 users
XLARGE = more than 1000 users
takes effect
If you create a server during installation.
After you edit your onconfig file and restart the database server for the first time.

Usage

If you create a server during installation, you specify the number of expected users for the database server. The AUTO_TUNE_SERVER_SIZE configuration parameter is set to the corresponding size, which affects the size of the following properties:

  • The size of the buffer pool.
  • The maximum size of logical log files before the server stops automatically adding logical logs to improve performance
  • The initial size of the following created storage spaces, which are created automatically during installation:
    • An extendable plogspace for the physical log
    • A dbspace for the logical log
    • Dbspaces for databases and tables
    • A temporary dbspace
    • An sbspace
    • A temporary sbspace

The following table shows how the value of the AUTO_TUNE_SERVER_SIZE configuration parameter affects sizes.

Table 1. Effect on memory and storage space allocations
Value Maximum size of buffer pools (BUFFERPOOL) Initial size of automatically created storage spaces Maximum size of logical log files (AUTO_LLOG)
SMALL 10% of available shared memory 50 MB 200 MB
MEDIUM 20% 100 MB 500 MB
LARGE 33% 200 MB 1 GB
XLARGE 50% 500 MB 2 GB

If you did not create a server during installation, or you change the value of the AUTO_TUNE_SERVER_SIZE configuration parameter after you initialize the server for the first time, the new value affects the size of only the following properties:

  • The size of the buffer pool, if the BUFFERPOOL configuration parameter setting includes the memory='auto' option.
  • The maximum size of all logical log files before the server stops automatically adding logical logs to improve performance.