2.6.2 Evaluating the configuration of the working directories for executing query groups

If you execute multiple query groups, you must evaluate the number of working directories to be used to execute the query groups.

To execute multiple query groups, the working directories and query groups can be configured to have a 1-to-1 correspondence or a 1-to-n correspondence. The table below describes each configuration.

Table 2-6 Configurations of query groups and working directories

No.ConfigurationDescription
1Configuration in which there is a 1-to-1 correspondence between a working directory and a query groupIn this configuration, you create one working directory for each query group and execute one query group in one working directory.
This configuration has the following advantages:
  • Performance is improved because memory space is divided among servers, thereby reducing the frequency of garbage collection.
  • Failures can be localized because a failure in one SDP server has no effect on query execution by other SDP servers.
Note that because you run only one SDP server per working directory, with this configuration you must have as many SDP servers as there are query groups.
2Configuration in which there is a 1-to-n correspondence between a working directory and multiple query groupsIn this configuration, you create only one working directory and execute multiple query groups in that working directory.
This configuration has the following advantages:
  • You only have to configure an operating environment once, which involves creation of the working directory, definition files, and adaptors.
  • Multiple query groups can be executed with fewer resources, compared with the configuration in which each query group is executed in its own working directory.

Note that if the memory requirement for a single SDP server exceeds 1.6 gigabytes, we recommend that you use the 1-to-1 configuration in which there is a working directory for each query group.

If you execute nine or more query groups, determine the number of working directories to be used to execute the query groups (creating as many 1:1 configurations as there are query groups or creating multiple 1: n configurations) by referencing 2.7 Estimating the memory requirements.