Instance View (DB2 LUW Performance Analyst)

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Go Up to IBM DB2 (W/U/L) Performance Analyst statistics

The IDERA Performance Analyst Instance view lets you review availability and overall performance of all monitored databases from a single window.

In addition to a Home page, the Instance category of DB2 Performance Analyst includes the following tabbed pages:

Home

Statistics on the Instance home view are organized into the following categories:

Agent Analysis Pane

The Agent Analysis section presents the following metrics:

Connections

The connections statistic gives the total Number of connections to databases in the current instance.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Agent Analysis Pane

Metrics

Shows the number of connections from remote/local clients to databases in this instance. This changes frequently, so you may need to sample it at specific intervals over an extended period of time to get a realistic view of system usage.

Correction

This element can help you adjust the setting of the max_coordagents configuration parameter.

Connections Executing

The connections executed statistic is the number if applications that are currently connected to a database and are currently processing a unit of work within the Database Manager instance being monitored.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Agent Analysis Pane

Metrics

The connections executing metric can help you determine the level of concurrent processing occurring on the Database Manager. This value can change frequently, so you may need to sample it at specific intervals over an extended period of time to get a realistic view of system usage

Correction

This element can help you adjust the setting of the maxcagents configuration parameter.

Agents Registered

The agents registered metric is the number of agents registered in the Database Manager instance that is being monitored (coordinator agents and subagents).

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Agent Analysis Pane

Correction

You can use this element to help evaluate your setting for the maxagents configuration parameter.

Agents Waiting

The number of agents waiting for a token so they can execute a transaction in the database manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Agent Analysis Pane

Metrics

Each application has a dedicated coordinator agent to process database requests within the Database Manager. Furthermore, each agent has to get a token before it can execute a transaction. The maximum number of agents that can execute Database Manager transactions is limited by the configuration parameter maxcagents.

Correction

You can use this element to help evaluate your setting for the maxcagents configuration parameter.

Idle Agents

The idle agents metric is the number of agents in the agent pool that are currently unassigned to an application and are, therefore, "idle.”

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Agent Analysis Pane

Metrics

Having idle agents available to service requests for agents can improve performance.

Correction

You can use this element to help set the num_poolagents configuration parameter.

Bottleneck Analysis Pane

The Bottleneck Analysis section presents the following metrics:

Post Threshold Sorts

This metric shows the number of sorts that have requested heaps after the sort heap threshold has been exceeded.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Bottleneck Analysis Pane

Metrics

Under normal conditions, the Database Manager allocates sort heap using the value specified by the sortheap configuration parameter. If the amount of memory allocated to sort heaps exceeds the sort heap threshold (sheapthres configuration parameter), the database manager allocates sort heap using a value less than that specified by the sortheap configuration parameter. Each active sort on the system allocates memory, which may result in sorting taking up too much of the system memory available. Sorts that start after the sort heap threshold has been reached may not receive an optimum amount of memory to execute. As a result, however, the entire system may benefit.

Correction

By modifying the sort heap threshold and sort heap size configuration parameters, the performance of sort operations and/or the overall system can be improved. If this element's value is high, you can: Increase the sort heap threshold (sheapthres) or, Adjust applications to use fewer or smaller sorts via SQL query changes.

Piped Sorts Rejects

The piped sorts rejects statistic is the number of piped sorts that were rejected by the database manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Bottleneck Analysis Pane

Metrics

Each active sort allocates memory, and can result in sorting taking up too much available system memory. A piped sort is not accepted if the sort heap threshold is exceeded when the sort heap is allocated for the sort. The sort list heap (sortheap) and sort heap threshold (sheapthres) configuration parameters help control the amount of memory used for sort operations. These parameters are also used to determine whether a sort will be piped. Since piped sorts may reduce disk I/O, allowing more piped sorts can improve the performance of sort operations and possibly the performance of the overall system.

Correction

If piped sorts are being rejected, you might consider decreasing your sort heap or increasing your sort heap threshold. You should be aware of the possible implications of either of these options. If you increase the sort heap threshold there is the possibility that more memory will remain allocated for sorting. This could cause paging memory to disk. If you decrease the sort heap, you might require an extra merge phase that could slow down the sort

Hash Join Thresholds

The hash join thresholds metric is the total number of times that a hash join heap request was limited because of concurrent use of shared or private sort heap.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Bottleneck Analysis Pane

Metrics

Each active sort allocates memory, and can result in sorting taking up too much of the available system memory. A piped sort is not accepted if the sort heap threshold is exceeded when the sort heap is allocated for the sort. The sort list heap (sortheap) and sort heap threshold (sheapthres) configuration parameters help control the amount of memory used for sort operations. These parameters are also used to determine whether a sort will be piped. Since piped sorts may reduce disk I/O, allowing more piped sorts can improve the performance of sort operations and possibly the performance of the overall system.

Correction

If this value is large (greater than 5% of Hash Join Overflows), the sort heap threshold should be increased.

Agents Waiting on a Token

The agents waiting statistic is the percentage of agents registered that are waiting for a token so they can execute a transaction in the Database Manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Bottleneck Analysis Pane

Metrics

Each application has a dedicated coordinator agent to process database requests within the Database Manager. Each agent has to get a token before it can execute a transaction. The maximum number of agents that can execute database manager transactions is limited by the configuration parameter maxcagents. This parameter is used to control the load on the system during periods of high simultaneous application activity. For example, you may have a system requiring a large number of connections but with a limited amount of memory to serve those connections. Adjusting this parameter can be useful in such an environment, where a period of high simultaneous activity could cause excessive operating system paging. This parameter does not limit the number of applications that can have connections to a database. It only limits the number of Database Manager agents that can be processed concurrently by the Database Manager at any one time, thereby limiting the usage of system resources during times of peak processing.

Correction

In cases where the high concurrency of applications is causing problems, you can use benchmark testing to tune this parameter to optimize the performance of the database.

Agents Created Due to Empty Pool

The agents created due to empty pool metric shows the number of agents created because the agent pool was empty. It includes the number of agents started when the current instance started (num_initagents).

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Bottleneck Analysis Pane

FCM Analysis Pane

The fast communication manager (FCM) provides communication support for Enterprise Server Editions. Each database partition server has one FCM thread to provide communications between database partition servers to handle agent requests and to deliver message buffers. The FCM thread starts when you start the instance.

The following ratios are used on the FCM Analysis section to succinctly communicate the general overall FCM performance levels of the monitored instance:

Buffer Throughput

The buffer throughput metric is the total number of buffers that have been sent and received by this database partition since the start of monitoring.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > FCM Analysis Pane

Metrics

This gives the level of traffic to and from the selected partition.

Correction

If this traffic level is high, you should consider redistributing one or more databases on the instance or move tables to reduce internode traffic.

Buffer Utilization

This element indicates the percentage of all FCM buffers currently being used by the fast communication manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > FCM Analysis Pane

Correction

You can use this information to tune fcm_num_anchors. If the utilization percentage is high, you should increase the fcm_num_anchors to ensure that operations do not run out of FCM message anchors. If the utilization is low, you can decrease fcm_num_anchors to conserve system resources.

Connection Entry Utilization

The connection entry utilization element indicates the percentage of all connection entries that are currently being used by the fast communication manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > FCM Analysis Pane

Correction

You can use this information to tune fcm_num_connect. If the utilization percentage is high, you should increase the fcm_num_connect to ensure that operations do not run out of FCM connection entries. If the utilization is low, you can decrease fcm_num_connect to conserve system resources.

Note: This metric is only applicable to DB2 version 7. In DB2 version 8, the maximum connection entries are adjusted dynamically and automatically

Message Anchor Utilization

This metric shows the percentage of all message anchors currently being used by the fast communication manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > FCM Analysis Pane

Correction

You can use this information to tune fcm_num_buffers. If the utilization percentage is high, you should increase the fcm_num_buffers to ensure that operations do not run out of FCM buffers. If the utilization is low, you can decrease fcm_num_buffers to conserve system resources.

Note: This metric is only applicable to DB2 version 7. In DB2 version 8, the maximum message anchors are adjusted dynamically and automatically

Request Block Utilization

This element indicates the percentage of all request blocks that are currently being used by the fast communication manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > FCM Analysis Pane

Correction

You can use this information to tune fcm_num_rqb. If the utilization percentage is high, you should increase the fcm_num_rqb to ensure that operations do not run out of FCM request blocks. If the utilization is low, you can decrease fcm_num_rqb to conserve system resources.

Note: This metric is only applicable to DB2 version 7. In DB2 version 8, the maximum request blocks are adjusted dynamically and automatically

Instance Information Pane

Here you see the following information:

Product Name

FixPack Level

Instance Type

Operating System

Instance Name

Number of Partitions

Active Local Databases

Key Ratio Analysis Pane

The Key Ratio Analysis section presents the following metrics:

Agents Registered

The agents registered metric shows the percentage of total allowable agents (coordinator agents and subagents) that are currently working in the instance.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Key Ratio Analysis Pane

Metrics

When this value is close to 100% it means that the number of agents currently working is close to the hard limit set in the database manager configuration. If this value stays high for long periods of time it means that there is high level of activity occurring in the databases on the instance.

Correction

Use this element to help you evaluate your setting for the maxagents database manager configuration parameter. When you increase the value of this parameter, make sure that your system has enough memory available to accommodate the additional agents that may be created.

Agents Waiting

The agents waiting statistic is the percentage of agents registered that are waiting for a token so they can execute a transaction in the Database Manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Key Ratio Analysis Pane

Metrics

Each application has a dedicated coordinator agent to process database requests within the Database Manager. Each agent has to get a token before it can execute a transaction. The maximum number of agents that can execute database manager transactions is limited by the configuration parameter maxcagents. This parameter is used to control the load on the system during periods of high simultaneous application activity. For example, you may have a system requiring a large number of connections but with a limited amount of memory to serve those connections. Adjusting this parameter can be useful in such an environment, where a period of high simultaneous activity could cause excessive operating system paging. This parameter does not limit the number of applications that can have connections to a database. It only limits the number of Database Manager agents that can be processed concurrently by the Database Manager at any one time, thereby limiting the usage of system resources during times of peak processing.

Correction

In cases where the high concurrency of applications is causing problems, you can use benchmark testing to tune this parameter to optimize the performance of the database.

Monitor Heap

This metric shows the percentage of total monitor heap that is currently being used by the Database Manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Key Ratio Analysis Pane

Metrics

The amount of memory required for monitoring activity depends on the number of monitoring applications (applications taking snapshots or event monitors), which switches are set, and the level of database activity. Memory is allocated from the monitor heap when you perform database monitoring activities such as taking a snapshot, turning on a monitor switch, resetting a monitor, or activating an event monitor.

If this metric is running at over 70% utilization and you have many applications performing snapshot /event monitoring, you may need to increase the size of the monitor heap.

Correction

Increase the value of mon_heap_sz database manager configuration parameter to increase the available monitor heap size.

FCMBP

The fast communication manager bufferpool (FCMBP) is the percentage of total amount of the FCMBP that is currently being used. This metric is only applicable to multipartitioned database environments.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Key Ratio Analysis Pane

Metrics

You can use this information to tune the fcm_num_buffers database manager configuration parameter.

Note: FCM buffers are used for internal communication both among and within database servers. The FCMBU metric gives the percentage utilization of the available fcm buffers in the Database Manager.

Private Sort Memory

The private sort memory metric is the percentage of the total private sort memory heap that is currently in use.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Home > Key Ratio Analysis Pane

Metrics

You can use this information to tune the sheapthres database manager configuration parameter. If the value of this element is close to 100%, it means that the sorts for some databases are not getting the full sort heap as defined by the sortheap database configuration parameter.

Configuration tab

The Configuration tab of the Instance Detail view lets you view and change the instance configuration parameter. It also allows you to look at some information about the instance such as Product Name, Type, Fixpak Level, Operating System, instance name, partitions, and number of active databases.

Agents & Connections tab

The Agents & Connections tab of the Instance Detail view gives you the following analyses:

Connection Analysis

This section presents the metrics for the current local and remote connections to databases in the instance. The information presented here includes:

  • Local Connections: The number of local applications that are currently connected to a database within the database manager instance being monitored.
  • Remote Connections: The current number of connections initiated from remote clients to the instance of the database manager that is being monitored.
  • Local Connections Executing: The number of local applications that are currently connected to a database within the database manager instance being monitored and are currently processing a unit of work.
  • Remote Connections Executing: The number of remote applications that are currently connected to a database and are currently processing a unit of work within the database manager instance being monitored.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Agents & Connections tab

Metrics

These metrics can help you determine the level of concurrent processing occurring in the database manager. These metrics will change frequently so it is important to obtain a sampling over an extended period. These metrics are useful when tuning the max_coordagents, and maxcagents database manager configuration parameters.

Agent Pool Analysis

The metrics in this section help determine how often the database agents are created due to empty pool and how often they are assigned from the agent pool.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Agents & Connections tab

Metrics

If the number of agents created due to empty pool is high compared to the agents assigned from pool, it may mean that the number of pool agents should be increased. It may also mean that the overall workload is too high.

Correction

You can change the maxcagents and num_poolagents database manager configuration parameters to tune these metrics.

Agent Analysis

The metrics presented here give a detailed view of how the database manager agents are working. The metrics presented here include:

  • Registered Agents: The number of agents registered in the database manager instance that is being monitored (coordinator agents and subagents).
  • Agents Waiting for Token: The number of agents waiting for a token so they can execute a transaction in the database manager.
  • Idle Agents: The number of agents in the agent pool that are currently unassigned to an application and are, therefore, "idle".
  • Stolen Agents: The number of times that agents are stolen from an application. Agents are stolen when an idle agent associated with an application is reassigned to work on a different application.
  • Maximum Agents Registered: The maximum number of agents that the database manager has ever registered, at the same time, since it was started (coordinator agents and subagents).
  • Maximum Agents Waiting: The maximum number of agents that have ever been waiting for a token, at the same time, since the database manager was started.
  • Maximum Coordinating Agents: The maximum number of coordinating agents working at one time.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Agents & Connections tab

Utilities tab

The Utilities tab of the Instance Detail View gives information on the utilities currently executing in the database manager. The Utility Execution Details are as follows:

  • Utility ID: The unique identifier corresponding to the utility invocation
  • Type: Class of the utility ( Rebalance, Backup, Restore, Reorg etc..)
  • Utility Description: A brief description of the work the utility is performing
  • Utility Start Time: The time the utility was invoked
  • DBName: Database on which the utility is operating.

FCM Resources tab

The FCM Resources tab of the Instances Detail View presents statistics on the following:


Node Details

This section gives a detailed view of inter- node communication in a multipartition environment. The information shown here includes the connection status and buffers sent and received between various combinations of partitions in a multi-partitioned environment. The columns presented here include:

  • Source Node: Partition that sends the information
  • Target Node: Partition that received the information
  • Buffers Sent: Number of Buffers sent from source node to the target node
  • Buffers Received: Number of Buffers sent from source node to the target node
  • Connection Status

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > FCM Resources tab IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > FCM Throughput tab

FCM Buffer Utilization

This section provides details on the current utilization and low watermark of FCM buffers.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > FCM Resources tab

Metrics

You can monitor the buffer utilization for the selected partition together with the low watermark to determine the usage trend of the fcm buffers.

Correction

If you notice a very small value for the low watermark and similar values for free FCM buffers over a long period, you may need to increase the fcm_num_buffers database manager configuration parameter to increase the number of available FCM buffers. If on the other hand you notice a very high value for the low watermark – you may have allocated too many buffers and you can reduce the value of fcm_num_buffers database manager configuration parameter.

FCM Message Anchor Utilitization

This section provides details on the current utilization and low watermark of FCM message anchors.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > FCM Resources tab

Metrics

You can monitor the message anchor utilization for the selected partition together with the low watermark to determine the usage trend of the message anchors.

Correction

If you notice a very small value for the low watermark and similar values for free message anchors over a long period, you may need to increase the fcm_num_anchors database manager configuration parameter to increase the number of available message anchors. If on the other hand you notice a very high value for the low watermark – you may have allocated too many message anchors and you can reduce the value of fcm_num_anchors database manager configuration parameter.

FCM Connection Entries Utilization

This section provides details on the current utilization and low watermark of FCM connection entries.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > FCM Resources tab

Metrics

You can monitor the connection entry utilization for the selected partition together with the low watermark to determine the usage trend of connection entries.

Correction

If you notice a very small value for the low watermark and similar values for free connection entries over a long period, you may need to increase the fcm_num_connect database manager configuration parameter to increase the number of available connection entries. If on the other hand you notice a very high value for the low watermark – you may have allocated too many connection entries and you can reduce the value of fcm_num_connect database manager configuration parameter.

FCM Request Block Utilization

This section provides details on the current utilization and low watermark of FCM request blocks.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > FCM Resources tab

Metrics

You can monitor the request block utilization for the selected partition together with the low watermark to determine the usage trend of the request blocks.

Correction

If you notice a very small value for the low watermark and similar values for free request blocks over a long period, you may need to increase the fcm_num_rqb database manager configuration parameter to increase the number of available request blocks. If on the other hand you notice a very high value for the low watermark – you may have allocated too many request blocks and you can reduce the value of fcm_num_rqb database manager configuration parameter.

FCM Throughput tab

The FCM Throughput tab of the Instance Detail VIew includes the following statistics:

The following statistic, available on this tab, duplicates a statistic available on the Instance View (DBArtisan - DB2 LUW Performance Analyst) FCM Resources tab:

FCM Throughput

This section shows the delta statistics for the FCM buffers sent and received between the selected nodes in the Node Details section

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > FCM Throughput tab

Metrics

If the total number of FCM buffers sent or received between selected nodes is high, you may want to redistribute the database, or move tables to reduce the inter-node traffic.

Memory Pools tab

The Memory Pools tab is divided into three panes. Unique to this tab is the Memory Pool List pane. The Memory Pool Details and the Memory Pool Utilization are duplicates of panes available in the Memory View (DB2 LUW Performance Analyst) category.

Memory Pool List pane

This section shows the memory pool usage details of the selected memory pool over time.

Sorts & Joins tab

The Sorts & Joins tab of the Instance Detail View presents the following information:

Sort Heap Details

This section shows the metrics for the total number of allocated pages of sort heap space for all sorts. It represents the sum of sort heap space allocated for all sorts in all active databases in the database manager.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Sorts & Joins tab

Metrics

Normal memory estimates do not include sort heap space. If excessive sorting is occurring, the extra memory used for the sort heap should be added to the base memory requirements for running the database manager. Generally, the larger the sort heap, the more efficient the sort. Appropriate use of indexes can reduce the amount of sorting required.

Correction

You may use the information in this section to help you tune the sheapthres configuration parameter. If the element value is greater than or equal to sheapthres, it means that the sorts are not getting the full sort heap as defined by the sortheap parameter.

Sort Threshold Details

This section details the number of sorts that have requested heaps after the sort heap threshold has been exceeded.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Sorts & Joins tab

Metrics

Under normal conditions, the database manager will allocate sort heap using the value specified by the sortheap configuration parameter. If the amount of memory allocated to sort heaps exceeds the sort heap threshold (sheapthres configuration parameter), the database manager will allocate sort heap using a value less than that specified by the sortheap configuration parameter. Each active sort allocates memory, which may result in sorting taking up too much of the system memory available. Sorts that start after the sort heap threshold has been reached may not receive an optimum amount of memory to execute, but, as a result, the entire system may benefit. By modifying the sort heap threshold and sort heap size configuration parameters, the performance of sort operations and/or the overall system can be improved.

Correction

If this element's value is high, you can: Increase the sort heap threshold (sheapthres) or, Adjust applications to use fewer or smaller sorts via SQL query changes.

Hash Join Threshold Details

This section shows the total number of times that a hash join heap request was limited due to concurrent use of shared or private sort heap space.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Sorts & Joins tab

Correction

If this value is large (greater than 5% of hash join overflows), the sort heap threshold should be increased

Piped Sort Details

This section gives the details on the piped sorts that have been requested and accepted.

Location

IBM DB2 (W/U/L) Performance Analyst statistics > Instance View (DBArtisan - DB2 LUW Performance Analyst) > Sorts & Joins tab

Metrics

Each active sort on the system allocates memory, which may result in sorting taking up too much of the available system memory. When the number of accepted piped sorts is low compared to the number requested, you can improve sort performance by adjusting one or both of the following configuration parameters: sortheap and sheapthres.

Correction

If piped sorts are being rejected, you might consider decreasing your sort heap or increasing your sort heap threshold. You should be aware of the possible implications of either of these options. If you increase the sort heap threshold, then there is the possibility that more memory will remain allocated for sorting. This could cause the paging of memory to disk. If you decrease the sort heap, you might require an extra merge phase that could slow down the sort.

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