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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 in the same way as the tableYou fragment an index in the same way that you fragment the table when you create a fragmented table and subsequently create an index without specifying a fragmentation strategy, unless the distribution scheme is round-robin and automatic location is enabled. Indexes on tables that use the round-robin distribution scheme are not fragmented when the AUTOLOCATE configuration parameter or environment option is set to a positive integer. You fragment an index in the same way that you fragment the table when you create a fragmented table and subsequently create an index without specifying a fragmentation strategy. The database server automatically creates an attached index when you first fragment a table.

Fragmenting the index in the same way as the table

You fragment an index in the same way that you fragment the table when you create a fragmented table and subsequently create an index without specifying a fragmentation strategy, unless the distribution scheme is round-robin and automatic location is enabled. Indexes on tables that use the round-robin distribution scheme are not fragmented when the AUTOLOCATE configuration parameter or environment option is set to a positive integer. You fragment an index in the same way that you fragment the table when you create a fragmented table and subsequently create an index without specifying a fragmentation strategy. The database server automatically creates an attached index when you first fragment a table.

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

CREATE TABLE tb1(a 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);

The database server fragments the index keys into dbspaces db1, db2, and db3 with the same column a value ranges as the table because the CREATE INDEX statement does not specify a fragmentation strategy.

Suppose 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 fragmentation strategy 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.