Home
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.
Effect of configuration on memory utilizationThe combination of operating-system and HCL OneDB™ configuration parameters can affect memory utilization.
Configure and monitor memory cachesThe database server uses caches to store information in memory instead of performing a disk read or another operation to obtain the information. These memory caches improve performance for multiple queries that access the same tables. You can set some configuration parameters to increase the effectiveness of each cache. You can view information about memory caches by running onstat commands.
Monitor and tune the SQL statement cacheThe SQL statement cache stores optimized SQL statements so that multiple users who run the same SQL statement can achieve some performance improvements.
Number of SQL statement executionsWhen the SQL statement cache is enabled, the database server inserts a qualified SQL statement and its memory structures immediately in the SQL statement cache by default.

Number of SQL statement executions

When the SQL statement cache is enabled, the database server inserts a qualified SQL statement and its memory structures immediately in the SQL statement cache by default.

If your workload has a disproportionate number of ad hoc queries, use the STMT_CACHE_HITS configuration parameter to specify the number of times an SQL statement is executed before the database server places a fully cached entry in the statement cache.

When the STMT_CACHE_HITS configuration parameter is greater than 0 and the number of times the SQL statement has been executed is less than STMT_CACHE_HITS, the database server inserts key-only entries in the cache. This specification minimizes unshared memory structures from occupying the statement cache, which leaves more memory for SQL statements that applications use often.

Monitor the number of hits on the SQL statement cache to determine if your workload is using this cache effectively. The following sections describe ways to monitor the SQL statement cache hits.