Use Hash Join Overflow and DBSPACETEMP
HCL OneDB™ uses an operating-system directory or file to direct any overflow that results from certain database operations, if you do not set the DBSPACETEMP environment variable or DBSPACETEMP configuration parameter.
You can specify the operating-system directory or file
in the following ways:
- SELECT statement with GROUP BY clause
- SELECT statement with ORDER BY clause
- Hash-join operation
- Nested-loop join operation
- Index builds
Location of the sort overflow files
The following table lists the
environment variables and ONCONFIG configuration parameters that you
can use to specify the location of the sort overflow files.
Variable or Parameter | Location of the sort overflow files |
---|---|
PSORT_DBTEMP environment variable | The location specified in the environment variable |
DBSPACETEMP environment variable | The location specified in the environment variable |
DBSPACETEMP configuration parameter specified in the ONCONFIG file | The dbspace that is specified in the ONCONFIG file DBSPACETEMP configuration parameter |
If more than one variable or parameter is specified,
the priority by which the HCL
OneDB determines
the location of the sort overflow files is:
- PSORT_DBTEMP environment variable
- DBSPACETEMP environment variable
- DBSPACETEMP ONCONFIG variable
- DUMPDIR
- $INFORMIXDIR/tmp
If the environment variables or configuration parameter are not set, the sort overflow files are placed in the $INFORMIXDIR/tmp directory and the temporary tables are placed in the rootdbspace.