지금 지원 담당자와 채팅
지원 담당자와 채팅

Foglight for Sybase 5.9.3.10 - User and Reference Guide

Using Foglight for Sybase
Exploring the Sybase Dashboards About the Sybase_MDA Agent About the Sybase_RS Agent Generating SybaseMDA Reports
Reference

Investigating Disk Performance

The Foglight Cartridge for Sybase assists your investigation into Sybase I/O use and availability by allowing you to:

Drill down on the Reads lines to see the SYBM_DiskIOSemaphores graph view to check if any semaphore contention exists on that device.

Investigating Index Performance

The Foglight Cartridge for Sybase assists your monitoring of general index performance metrics. You can use this information to analyze your application workload.

Investigating Locking

The Adaptive Server protects the tables or data pages currently used by active transactions by locking them. Locking is a concurrency control mechanism: it ensures the consistency of data across transactions. Locking is needed in a multi-user environment, since several users may be working with the same data at the same time.

Locking affects performance when one process holds locks that prevent another process from accessing needed data. The process that is blocked by the lock sleeps until the lock is released.

The Foglight Cartridge for Sybase assists your investigation into locking performance in the Adaptive Server by measuring specific locking characteristics of your server.

Open the SYBM_LockSummary graph view to display the number of locks requested on the system, locks that had to wait to be granted, locks that timed out, and the number of deadlocks on the system.
Drill down on the locks time out to view the SYBM_LockWaitTime graph view to display the average wait time for locks. Use this chart to discover any specific period of time where the performance noticeably degrades. Investigate respective user and application activity during this time frame using one of the SYBM_ResourcesInUse or one of the SYBM_Top Foglight views.

The number of locks required by a query can vary widely, depending on the locking scheme, the number of concurrent and parallel processes and the types of actions performed by the transactions. Configuring the correct number for your system is a matter of experience and familiarity with the system.

System administrators can use sp_configure to change this limit. For example:

You may also need to adjust the sp_configure parameter total memory, since each lock uses memory.

A shortage of the number of locks available can have an impact on the overall locking scheme in place on the server.

Investigating Meta Data Cache Contention

The Foglight Cartridge for Sybase assists your investigation into the performance characteristics of the Metadata Cache.

The Metadata caches reside in the kernel and server structures portion of Adaptive Server memory. You configure space for each of these caches by defining the number of each type of cache that the server allocates. This is done with the respective properties to the Sybase system procedure sp_configure.

Tracking and managing individual metadata caches for databases, indexes, or objects is important for a database that contains a large number of indexes and objects and where there is an expectation of high concurrency among users.

IMPORTANT: The Adaptive Server uses the metadata cache: When the Adaptive Server opens a database or accesses an index or an object, it needs to read information in the respective system tables: sysdatabases, sysindexes, and sysobjects.

The metadata caches for databases, indexes, or objects let the Adaptive Server access the information that describes it in the sysdatabases, sysindexes, or sysobjects row that are directly in its in-memory structure. This improves performance by allowing the Adaptive Server to bypass expensive calls that require disk access. Synchronization and spin lock contention are also reduced when the Adaptive Server has to retrieve database, index, or object information during runtime.
관련 문서