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 next to the metric on the Resources tab. The Information link is not available for all metrics.
If the database instance runs on a virtual machine (VM), metrics collected for the VM are described in VM metrics collected by DPA

Connections

Metric	Description
Connected Devices	The number of distinct client machines connected to this instance (even if the connection is idle).
Connected Users	The number of distinct users connected (that is, distinct logins) to this instance (even if the connection is idle).
Sessions	The number of sessions connected to this instance (even if the connection is idle).

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".
Core Count	The number of cores used by the instance.

Metric	Description
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".
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 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 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".
Disk I/O Access Time	The average time to read from or write to disk.

Metric Description

Buffer Cache Hit Ratio

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.

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.

Metric	Description
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 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 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.

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.

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