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AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
System administrationThese topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL OneDB™ database servers.
Performance GuideThe HCL OneDB™ Performance Guide describes how to configure and operate your HCL OneDB™ database server to improve overall system throughput and to improve the performance of SQL queries.
Fragmentation guidelinesOne of the most frequent causes of poor performance in relational database systems is contention for data that resides on a single I/O device. Proper fragmentation of high-use tables can significantly reduce I/O contention. These topics discuss the performance considerations that are involved when you use table fragmentation.
Improve the performance of operations that attach and detach fragmentsWhen you use ALTER FRAGMENT ATTACH and DETACH statements to add or remove a large amount of data in a very large table, you can take steps to improve the performance of the ATTACH and DETACH operations.
Improving ALTER FRAGMENT DETACH performanceYou can improve the performance of ALTER FRAGMENT DETACH statements by formulating appropriate distribution schemes for your table and index fragments and by eliminating the index build during the execution of ALTER FRAGMENT DETACH statements.
Fragmenting the index using same distribution scheme as the tableYou fragment an index with the same distribution scheme as the table when you create the index that uses the same fragment expressions as the table.

Fragmenting the index using same distribution scheme as the table

You fragment an index with the same distribution scheme as the table when you create the index that uses the same fragment expressions as the table.

A common fragmentation strategy is to fragment indexes in the same way as the tables but to specify different dbspaces for the index fragments. This fragmentation strategy of putting the index fragments into different dbspaces from the table can improve the performance of operations such as backup and recovery.

For example, suppose you create a fragmented table and index with the following SQL statements:

CREATE TABLE tb1(a int, b int) 
   FRAGMENT BY EXPRESSION
      (a >=0 AND a < 5) IN db1,
      (a >=5 AND a <10) IN db2,
      (a >=10 AND a <15) IN db3;

CREATE INDEX idx1 on tb1(a)
   FRAGMENT BY EXPRESSION
      (a >=0 AND a< 5) IN db4,
      (a >=5 AND a< 10) IN db5,
      (a >=10 AND a<15) IN db6;

Suppose that you then decide to detach the data in the third fragment with the following SQL statement:

ALTER FRAGMENT ON TABLE tb1 
   DETACH db3 tb3;

Because the distribution scheme of the index is the same as the table, the ALTER FRAGMENT DETACH statement does not rebuild the index after the detach operation. The database server drops the fragment of the index in dbspace db3, updates the system catalog tables, and eliminates the index build.