Creating a dbspace with a non-default page size
You can specify a page size for a standard or temporary dbspace if you want a longer key length than is available for the default page size.
About this task
The root dbspace uses the default page size. If you want to create a dbspace with a different page size, the size must be an integral multiple of the default page size, and cannot be greater than 16 KB.
- Reduced depth of B-tree indexes, even for smaller index keys.
- Decreased checkpoint time, which typically occurs with larger page sizes.
- Group on the same page long rows that currently span multiple pages of the default page size.
- Define a different page size for temporary tables, so the temporary tables have a separate buffer pool.
A table can be in one dbspace and the index for that table can be in another dbspace. The page size for these partitions can be different.
Procedure
- If you upgraded from a version before version 10.00, run
the onmode -BC 2 command to enable the large chunk
mode. By default, when HCL Informix® is first initialized or restarted, Informix® starts with the large chunk mode enabled.
- Optional:
Create a buffer pool that corresponds to the page size of the
dbspace. You can use the onparams utility or the
BUFFERPOOL configuration parameter.
If you create a dbspace with a page size that does not have a corresponding buffer pool, Informix® automatically creates a buffer pool using the default values for the BUFFERPOOL configuration parameter as defined in the onconfig file.
You cannot have multiple buffer pools with the same page size.
- Define the page size of the dbspace when you create the dbspace. You can use the onspaces utility.