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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 ATTACH performanceYou can take advantage of the performance optimizations for the ALTER FRAGMENT ATTACH statement if your database meets certain requirements.
Distribution schemes for reusing indexesYou can use one of three distribution schemes that allow the attach operation of the ALTER FRAGMENT statement to reuse existing indexes.
Attaching unfragmented tables togetherYou can take advantage of the performance benefits of the ALTER FRAGMENT ATTACH operation when you combine two unfragmented tables into one fragmented table.

Attaching unfragmented tables together

You can take advantage of the performance benefits of the ALTER FRAGMENT ATTACH operation when you combine two unfragmented tables into one fragmented table.

For example, suppose you create two unfragmented tables and indexes with the following SQL statements:

CREATE TABLE tb1(a int) IN db1; 
   CREATE INDEX idx1 ON tb1(a) in db1;
CREATE TABLE tb2(a int) IN db2; 
   CREATE INDEX idx2 ON tb2(a) in db2;

You might want to combine these two unfragmented tables with the following sample distribution scheme:

ALTER FRAGMENT ON TABLE tb1 
   ATTACH 
      tb1 AS (a <= 100),
      tb2 AS (a > 100);

If no data migrates between the fragments of tb1 and tb2, the database server redefines index idx1 with the following fragmentation strategy:

CREATE INDEX idx1 ON tb1(a) F
   FRAGMENT BY EXPRESSION
      a <= 100 IN db1,
      a > 100 IN db2;

Important: This behavior results in a different fragmentation strategy for the index prior to version 7.3 and version 9.2 of the database server. In earlier versions, the ALTER FRAGMENT ATTACH statement creates an unfragmented detached index in the dbspace db1.