SQL/MP Installation and Management Guide

Managing a Distributed Database
HP NonStop SQL/MP Installation and Management Guide—523353-004
12-9
Dropping Distributed Objects
Dropping Distributed Objects
When you DROP or PURGE a distributed table, all indexes, partitions, and views must
be accessible, in addition to the catalogs that describe these objects. If you do not
have the authority to drop a shorthand view, the operation only invalidates the view.
When you specify dropping any partition of a table or index, the operation drops the
entire table or index. You cannot specify a DROP, PURGE, or PURGEDATA operation
on any individual partition.
You can also drop empty partitions of a table or index with the ALTER TABLE or
ALTER INDEX statement. Dropping partitions is discussed in Dropping Partitions of
Tables and Indexes on page 7-32.
Enhancing Performance for a Distributed
Database
The performance issues of a distributed database encompass those of a local
database and also include these:
•
Effective use of local partitions or indexes
•
Use of replicated data to increase local performance
•
Use of remote servers to increase performance
These issues, not covered in this manual, also affect performance of a distributed
database:
•
Network availability and use
•
Remote node availability
For additional information about enhancing performance, see Section 14, Enhancing
Performance.
Using Local Partitions and Indexes
Defining local partitions of a table, so that the local partition can satisfy a significant
number of local queries, can improve performance. Also, the local partition remains
available to satisfy the queries even when other nodes are unavailable.
Performance might also improve for queries on a remote table if a local index exists to
resolve queries locally. If the local index columns can resolve a query, the SQL
executor does not need to query the remote table.
Before defining the index or local partitions, you must weigh the benefits against any
performance considerations that occur when the underlying table is modified. Insert,
update, or delete operations on the table from anywhere in the network also require
access to the local index and possibly to the local partition.