Documentation forDatabase Performance Analyzer

Sybase metrics collected by DPA

The following sections list the metrics that DPA collects for Sybase database instances.

  • Learn how to view these metrics and change the thresholds.
  • For detailed information about resolving issues, click the Information link next to the metric on the Resources tab. The Information link is not available for all metrics.

CPU

Metric Description
CPU Utilization By Sybase The percentage of CPU being used by the database instance, which is a subset of the CPU used by the entire system. If this is high, use DPA's Trends charts to review queries with the wait type "waiting on run queue after sleep".

Memory

Metric Description
Buffer Cache Hit Ratio

The rate at which Sybase finds the data blocks it needs in memory rather than having to read from disk.

By itself, the buffer cache hit ratio is not very meaningful except for servers with undersized memory settings.

Tuning queries and performing index optimization is the best way to increase buffer cache hit ratios.

To determine the current sizes of the data caches, use the sp_helpcache command.

Procedure Cache Hit Ratio

The percentage of time Sybase finds an available plan already in cache.

If this is low, try to write more reusable code and/or consider increasing the size of the procedure cache.

To determine the current size of the procedure cache, review the value of the procedure cache size parameter.

Disk

Metric Description
DB Physical I/O Rate The number of read and write operations that this Sybase server performed to or from disk every second. If this is high, drill in to the DPA Trends charts and review physical read and write wait types.
DB Physical Write Rate The number of write operations this Sybase server performed to disk every second. If this is high, drill in to the DPA Trends charts and review queries with write wait types, such as "waiting for disk write to complete".
DB Physical Read Rate The number of read operations this Sybase server performed from disk every second. If this is high, drill in to the DPA Trends charts and review queries with physical read wait types, such as "waiting for i/o (read or write) to complete".
DB APF Read Rate The number of Asynchronous Prefetch (APF) reads this Sybase server performed from disk every second. If this is high, drill in to DPA Trends charts and review queries with wait types of "waiting for an APF buffer read to complete".
Disk I/O Access Time The average time to read from or write to disk.

Network

Metric Description
DB Network Send Rate The number of bytes sent over the network every second for this database. If this is high, drill in to the DPA Trends charts and review queries with network wait types (for example, "waiting for network send to complete").
DB Network Receive Rate The number of bytes received over the network every second for this database. If this is high, drill in to DPA Trends charts and review queries with network wait types (for example, "waiting for incoming network data").
DB Round-trip Time The round-trip time when running "select 1" (includes network time but not connect time) on this database. If this is high, contact your network administrator to understand network latency.

Sessions

Metric Description
DB Active Sessions The number of sessions actively performing work or waiting for a resource (excludes idle sessions).
DB Blocked Sessions The number of sessions that are blocked because another session is using a needed resource.

Waits

Metric Description
Total Instance Wait Time The total wait time for the instance.

License Compliance

Metric Description
Connected Users The number of distinct users connected (that is, distinct logins) to this instance (even if the connection is idle). This value is typically used for per-user licensing.
Connected Devices The number of distinct client machines connected to this instance (even if the connection is idle). This value is typically used for per-device licensing. It can also be used to approximate per-user licensing.
Sessions The number of sessions connected to this instance (even if the connection is idle). This value is typically used for licensing based on number of concurrent connections.
Core Count The number of cores used by the instance. This value is typically used for per-core licensing.