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- About the Tier entity
- About the Instance entity
- About the Engine entity
- About the Device entity
- About the Data Cache entity
- About the Performance Counter or Counter Instance entity
- About the Wait Events entity
- About the Replication Server entity
- About the Replicate(d) Databases entity
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For an explanation on how to define instance groups, see the Precise Installation Guide. The table below describes the information displayed in the Instance Grouping table.
Table 8- 1 Instance Grouping table
Item | Description |
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Group | Displays the name of the group. |
Instances | Displays the number of instances linked to the group. |
Engine Utilization | Displays the average Engine Utilization for the instances in the specified group. |
Committed Transactions | Displays the SUM number of Committed Transactions for the instances in the specified group. |
Connections Opened (Sum) | Displays the sum of opened connections for the instances in the specified group. |
About viewing instances associated with an Tier in the Association area
Displays information on the Instances associated with the selected Tier in the Association area. The table below describes the information displayed in the tabs in the Association area.
Table 8- 2 Viewing information on associated instances
Tab | Description |
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Overview | Displays counters reporting on CPU Usage, Memory Usage and amount of Locked Data. |
Network | Displays counters reporting on the number of times an engine polls incoming and outgoing packets and bytes. |
Disk I/O | Displays various counters reporting on the amount of disk I/O. |
Transactions | Displays counters reporting on the number of rows changed in the instance, grouped by type (insert, update, and delete). |
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The Replication Inbound view is a combination of a few predefined graphs related to the inbound processing phase (replication agent); the view helps you identify what may be causing the latency in the replication system. The information displayed in the Instance level is a summation of all the replicated databases of the instance.
Table 8- 3 I/O vs Cmds Sent
Graph | Description |
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IO vs. Cmds Sent | Highlights The IO vs. Cmds Sent graph shows the number of commands processed by the RepAgent during the given period and the amount of time the RepAgent had to wait while writing to the inbound queue. Each bar represents a time period. The speed of the RepAgent is directly proportional to the speed of ASE processing the network that sends requests coupled with the speed of the Replication Server processing. What to do next
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Table 8- 4 Truncation Point Movement
Graph | Description |
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Truncation Point Movement | Highlights The Truncation Point Movement graph shows the number of times the RepAgent has asked the RS for a new secondary truncation point and then moved the secondary truncation point in the log. If 'Moved' is more than one less than 'Gotten', the likely cause is that a large or open transaction exists from the Replication Server perspective (either it is indeed still open in ASE or the RepAgent has not forwarded the commit record yet). What to do next
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Table 8- 5 Network
Graph | Description |
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Network | Highlights The Network graph shows information related to the network activity. If the Number of Full Packets is a considerable percentage out of the total package sent (>= 90%), then you may need to consider increasing the send_buffer_size. What to do next
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Table 8- 6 Log Scan Summary
Graph | Description |
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Log Scan Summary | Highlights The Log Scan Summary graph is an indicator of how much work the RepAgent is doing and how much information is being sent to the Replication Server. Replicated log records are records converted into LTL and sent to the RS. Not replicated log records are all log records that were scanned but not sent. What to do next
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Table 8- 7 Replicated Commands Breakdown
Graph | Description |
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Replicated Commands Breakdown | Highlights The Replicated Commands Breakdown lists the number and type of commands that were replicated and which most affect the replication.
What to do next
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About viewing Replication Outbound view graphs
The Replication Outbound view graphs view is a combination of a few predefined graphs related to the outbound processing phase. This enables you to understand what specific component(s) may be causing the latency in the replication system. The information displayed in the instance level is a summation of all the outbound processing performed for the specified instance by all the Replication servers attached to it.
Table 8- 8 SQM Processing
Graph | Description |
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SQM Processing | Highlights The SQM Processing graph shows the space usage of SQM queue overtime versus the number of commands written to the queue. The SQM Commands Written indicates the amount of activity performed by the replication server. What to do next
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Table 8- 9 DSI SQT Processing
Graph | Description |
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DSI SQT Processing | Highlights The DSI SQT Processing graph shows space usage of the outbound queue cache. The Cache size lists the size of the SQT cache. Cached Used shows SQT thread memory usage over time. Each command structure (allocated by an SQT thread) is freed when its transaction context is removed. Consequently, if no transactions are active in SQT, then SQT cache usage is zero. If Cached Used is near the maximum cache size capacity and Trans Removed is constantly greater than zero, you may decide to increase the SQT cache size by increasing dsi_sqt_max_cache_size. Don’t increase the cache size if Trans Removed is occasionally greater than zero; this situation usually means that a transaction was removed from the cache because it was greater than the dsi_sqt_ max_cache_size. For occasional increases of Trans Removed, increasing the cache size will have the opposite effect because the latency in processing transactions ahead of them will likely result in their being removed. The SQM Read Cached indicates how many 16K blocks of cache were read by the SQM Reader thread. This number should be as high as possible. If it is constantly hitting zero, most likely there is a latency in executing the SQL at the replicate; resulting in the DSI SQT cache to reach its maximum. What to do next
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Table 8- 10 DSIE Transactions Processing
Graph | Description |
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DSIE Transactions Processing | Highlights The DSIE Transactions Processing graph shows how long it took to process a transaction by a DSI/E thread breakdown to various phases.
What to do next
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Table 8- 11 DSIE Commands Applied
Graph | Description |
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DSIE Commands Applied | Highlights The DSIE Commands Applied graph shows how many commands were successfully applied to the target database by DSI/E overtime (relevant for version 15 and higher). It can be used to measure the amount of work imposed by the replication server. You can also compare that number to the SQM Commands Written and check if there is a lag in processing commands inside the replication server. What to do next
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The Device entity displays predefined graphs that report on device activity and performance. The following views are available:
- Overview
- Semaphores
About getting an overview on a Device activity
The Overview displays an overtime graph, which represents Page Requests (read and write) of the device. The following information is displayed:
- Page
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- Requests. Displays the number of pages read synchronous or asynchronous and the number of pages that are written.
About viewing Semaphores
The Semaphores view displays an overtime graph, which represents Semaphore Hits and Misses. The following information is displayed:Semaphores Displays
- Semaphores. Displays the number of times that a request for a device semaphore was granted immediately and the number of times the semaphore was busy and the task had to wait for the semaphore to be released.
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The Data Cache entity displays predefined graphs that report on the activity of the Data Cache. The following views are available:
- Overview
- Cache details
About getting an overview on Data Cache activity
The Overview displays statistics that report on the Data Cache Hit Ratio and Utilization. The following information is displayed:
- Hit
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- Ratio. Displays the percentage of time a requested page was found in a cache and was found in the wash area.
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- Utilization. Displays the percentage of searches using this cache, as a percentage of searches across all caches.
About viewing Cache Details
The Cache Details view displays statistics that report on the Data Cache Buffer Wash (Pages) and large I/Os. The following information is displayed:
- Buffer Wash (Pages)
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- . Displays the number of buffers that were clean when they passed the wash marker, the number of times that I/O was already active on a buffer when entered the wash area, and the number of times that a buffer entered the wash area dirty and was not already in I/O.
- Large I/
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- O. Displays the number of times a large I/O was requested for a buffer and the number of times it was denied.
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The Performance counter or Counter Instance entity displays statistical information on the selected counter. Precise for Sybase collects counters reported by Sybase. These counters determine which aspects of the objects to monitor. For example, the Sybase Memory Object contains the Mempages_alloced counter.
The Overview displays general details of the selected counter and overtime graph, which represent the counter value. In some of the selected counters, two overtime graphs are displayed: a graph that displays the number of transactions over time and another graph that displays the counter value per committed transaction.
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Available for Sybase versions 12.5.0.3 and higher, the Wait Events entity displays the name of the wait event group, the number of waits experienced by this event group and the summed amount of time accumulated by wait events and summed occurrences.
The following view is displayed:
- Overview
About getting an overview of Wait Events
The Overview displays general details of the selected counter. The following information is available:
- Event
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- group. Displays the name of the wait type.
- Event
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- name. Provides a description of what is causing the event.
- Time waited (avg)
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- . Average time waited for wait events, over the selected time period.
- Times waited
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- graph. Displays the time waited for wait events vs. the time waited for group events.
- Wait
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- graphs. Displays the number of wait events vs. the number of wait events for group events.
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The Replication Server entity displays predefined graphs which represent statistics related to the outbound processing phase and inbound (repagent statistics) processing phase for the selected Replication Server in the Selected time frame.
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The Precise for Sybase Replication server collector agent collects statistics only for the Sybase ASEs which are monitored by Precise and use the specified replication server for replicating data. If the same RS also serves other ASEs that are not monitored by Precise or another RDBMS (such as: Oracle, SQL Server, etc.), the statistics of those instances will not be collected and displayed. |
The following views are available:
- Replication Inbound
- Replication Outbound
See About the Instance entity on page 85.
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The Replicate(d) databases entity displays predefined graphs which represent statistics related to the outbound processing phase and inbound (repagent statistics) processing phase for the selected database in the Selected time frame.
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The Precise for Sybase Replication server collector agent collects statistics only for the Sybase ASEs that are monitored by Precise and use the specified replication server for replicating data. If the same RS also serves other ASEs that are not monitored by Precise or another RDBMS (such as: Oracle, SQL Server, etc.), the statistics of those instances will not be collected and displayed. |
The following views are available:
- Replication Inbound
- Replication Outbound
See About the Instance entity on page 85.
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You can identify a performance problem by doing one or more of the following:
- Examining the kernel utilization of Sybase over time
- Examining I/O statistics
- Examining network activity
- Examining memory bottlenecks
- Examining a specific counter over time
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You can examine a Sybase instance over time to confirm that the amount of Sybase engines configured in your system is optimal.
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The table below describes what the utilization status of an engine indicates.
Table 8- 12 Utilization status
Engine Busy | CPU Yields | Status |
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Low | Low | Engine is CPU starved |
Low | High | Engine is inactive |
High | Low | Engine is busy |
High | High | Engine is busy |
To improve kernel utilization, it is recommended to check the Disk I/O and Network view. This is done to determine if the number of checks for I/O or Network that the engine performs, is ideal or are overhead.
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If the sample includes idle time, or the I/O traffic is "bursty," , it is possible that a high percentage of the checks were returning I/O during the busy period. If the results in this category seem low or high, you can configure the frequency of the checks.
Increasing the amount of time that Adaptive Server engines wait between checks may result in better throughput, because Adaptive Server engines can spend more time processing if they spend less time checking for I/O.
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To examine I/O statistics
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You can also use this information to check I/O distribution patterns over the disks and to make object placement decisions that can help balance Disk I/O across devices. For example, does the data show that some disks are more heavily used than others? If you see that a large percentage of all I/O went to a specifically named device, you can investigate the tables residing on the device and then determine how to remedy the problem.
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You can examine network traffic over a specified time period to detect bottlenecks. Network performance can be improved by one or more of the following:
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- Switch to the Network view.
- Check the ratio between the Packets graph and the Bytes graph to see if the network packet size is used to its maximum capacity.
- Consider configuring its size.
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Lack of memory or a high memory consumption rate can cause paging. A page fault occurs when a process requires code or data that is not in its working set (its space in physical memory), thereby causing the page to be retrieved from disk and written to the physical memory. If there is not enough space in the physical memory, a chosen page needs to be written to disk to free space.
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- Examine the Memory view that reports the number of pages allocated and deallocated in each time slice.
- If you spot a high value in one of the time slices, open the Activity tab to continue your analysis of the application's performance.
- Switch to the Memory view to see information about the success and failure of Memory Requests for Worker Processed in the Memory Requests graph.
- If some of the requests have failed you may need to increase the value of the
Memory per Worker Process
parameter. - Switch to Data Cache view to see information on how effective cache design is. A high Hit Ratio from the Hit Ratio graph and small amount of Page Request Misses from the Utilization graph may indicate effective cache design.
- If you see a low Hit Ratio and a lot of Page Request Misses, investigate statistics for each of the Data Caches by selecting the Data Cache entity in the Association area.
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A wide range of performance counters generated by Sybase are collected by the Precise for Sybase collect instance statistics process. These performance counters are sampled every 15 minutes and displayed in this tab over time.
A performance group is a Sybase Performance Group resource, such as a Sybase Lock. Each performance group contains a few counters that determine which performance aspects to monitor. For example, the Sybase Memory Performance group contains counters called Pages Allocated (Sybase counter: mempages_alloced
) and Pages Released (Sybase counter: mempages_freed
).
Some performance counters have separate instances. An instance refers to a particular occurrence of a counter. For example, the Device-Counters Performance group has counters such as Disk Cache Misses (Sybase counter: p_misses
) and Disk Cache Hits (Sybase counter: p_hits
), but because several devices exist, each counter is divided into instances.
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- Select the associated required performance group from the Associations list.
- Select the required counter.
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