Pivotal Greenplum® Command Center 3.2.2 Release Notes

Greenplum Command Center version: 3.2.2

Greenplum Workload Manager version: 1.8.0

Published: June, 2017

About This Release

Pivotal Greenplum Command Center release 3.2.2 contains Greenplum Command Center release 3.2.2 and Greenplum Workload Manager release 1.8.0.

See Enhancements and Changes in Greenplum Command Center 3.2.2 for information about new features and improvements in the Greenplum Command Center 3.2.2 release.

See Enhancements and Changes in Greenplum Workload Manager 1.8.0 for information about new features and improvements in the Workload Manager 1.8.0 release.

Supported Platforms

Greenplum Command Center may be installed on the following platforms:

• Red Hat Enterprise Linux 5, 6, or 7, 64-bit
• CentOS 5, 6, or 7, 64-bit
• SUSE Linux Enterprise 11SP4, 64-bit

Greenplum Workload Manager may be installed on the following platforms:

• Red Hat Enterprise Linux 5.5+ or 6, 64-bit
• CentOs 5.5+ or 6, 64-bit
• SUSE Linux Enterprise 11SP4, 64-bit

The following table shows Greenplum Command Center and Greenplum Database version compatibility.

Pivotal Documentation

Pivotal Greenplum Command Center and Pivotal Greenplum Workload Manager documentation is available on the Pivotal Documentation site at http://gpcc.docs.pivotal.io/.

About Pivotal Greenplum Command Center

Pivotal Greenplum Command Center (GPCC) is a management tool for Pivotal Greenplum Database. GPCC monitors query activity and system performance metrics. Pivotal Greenplum Command Center is an interactive graphical web application that can be installed on the master host and used to view and interact with the collected system data from Greenplum Database.

Greenplum Database is a requirement for operating Command Center because Command Center relies on information stored in the Greenplum gpperfmon database. Greenplum Database includes data collection agents that run on the Greenplum Database master host and each segment host. The agents collect data about queries and system utilization and send them to the Greenplum master host at regular intervals. Data stored in the gpperfmon database can be accessed through the Command Center web application or with SQL queries.

Enhancements and Changes in Greenplum Command Center 3.2.2

• Performance enhancements for Segment Health and Alerts.
• Greenplum Command Center 3.2.2 includes beta support for viewing and authoring Greenplum Workload Manager rules. If Workload Manager is running on the master host, Greenplum Command Center includes the Admin>Workload Mgmt page. Command Center users with Admin permission level can view, add, edit, and delete Workload Manager rules. Users with operator permission level can view, but cannot change, current Workload Manager rules. The GPCC Workload Manager integration is not currently supported on remote Command Center instances.
• An issue where line breaks were not preserved in queries displayed in the GPCC Query History is fixed in the gpperfmon monitoring agents in Greenplum Database release 4.3.14.0.

Enhancements and Changes in Greenplum Command Center 3.2.0

Greenplum Command Center 3.2.0 contains the following enhancements:

• Hardware Status monitoring for DCA-hosted clusters
• Performance improvements and bug fixes

Enhancements and Changes in Greenplum Command Center 3.1.1

Greenplum Command Center 3.1.1 contains the following enhancements:

• Fixed a bug introduced in 3.1.0 that refused passwords with special characters
• Fixed a bug introduced in 3.1.0 that prevented long pages from scrolling
• More robust hostname detection for Host Metrics and Storage Status

New Known Issues:

• When multiple queries are submitted as a single statement, cannot run explain because all queries in the statement are included in query text (gpperfmon issue)
• Line breaks in queries are not preserved in query history (gpperfmon issue)

Enhancements and Changes in Greenplum Command Center 3.1.0

Greenplum Command Center release 3.1.0 contains the following new features and enhancements:

• Manage Command Center user roles in the Administration > Permissions view.
• New Command Center permission levels “Basic” and “Operator Self Only”.
• View and edit the Greenplum Database pg_hba.conf authentication configuration file in the new Administration > Authentication view.
• View recent messages from the Greenplum Database pg_log file in the Alerts panel on the Dashboard.
• On the Cluster Metrics view, you can choose metrics to show or hide.
• Clusters on the Multi-cluster page can be protected by adding a list of allowed roles to the clusters’ entries in the Multi-cluster configuration file.
• The installer provides an option to install the Command Center software on the standby master.
• OpenSSL libraries are no longer bundled with Greenplum Command Center. The web server continues to support SSL connections and user authentication. However, the gpcmdr --setup command no longer provides an option to generate a self-signed certificate. You must install your own server certificate and import it when you create a Command Center instance.
• Experimental support for authenticating Command Center users with Kerberos. If you want to use this feature, please work with Pivotal to ensure that it is correct for your environment.
• Support for Greenplum Command Center with a Greenplum Database 5.x system.

Enhancements and Changes in Greenplum Command Center 3.0.1

Greenplum Command Center release 3.0.1 addresses the following issues in Greenplum Command Center release 3.0.0:

• Hosts with hostnames changed since the initial Greenplum Database installation not appearing in host and cluster metrics
• Manual 4-digit entry into History time fields
• Temporary display of zero value for cluster metrics when under high load
• Count and sort in History queries grid
• gpcmdr --restart not reliably bringing gpmonws back up
• gpcmdr --version
• History charts can cut off edges of timespan

Enhancements and Changes in Greenplum Command Center 3.0.0

The Greenplum Command Center software is brand new for this release. A native HTML5 front-end and Go backend replace the previous Flash and Python application.

New Technology

• Native HTML5 frontend – no Flash, no browser plugin required
• Completely new backend written in Go
• Same data collection agents, same gpperfmon database schema – no corresponding changes in Greenplum Database

New Upgrade Process

• Preserve your instance configurations with the new gpcmdr --migrate command option

New Console UI

• Reorganized Dashboard view
• More responsive Query Monitor and Query Details views
• Host Metrics view with new skew severity indication
• Cluster Metrics view with synchronized charts
• History browser view featuring user-defined timespan, integrated charts and query list, pan and zoom timeframe
• System monitoring views for Storage and Segment status

Greenplum Command Center Compatibility

Pivotal Greenplum Command Center is currently certified for the EMC Data Computing Appliance (DCA) and Greenplum Database software-only environments. Command Center monitors the following for each environment:

Greenplum Data Computing Appliance

• Greenplum Database Module 4.3.x

If you have been using Greenplum’s earlier monitoring tool, Performance Monitor, with an older DCA release, we recommend you upgrade to a supported version of DCA.

Greenplum Database (Software-only Environments)

• Greenplum Database 4.3.x
• Greenplum Database 5.x

Command Center Installation and Upgrade Instructions

There is now an upgrade path for all 1.x, 2.x, and 3.x versions. See gpcmdr --migrate for details.

DCA and Greenplum Database Software-only

Instructions for installing, configuring, and upgrading your system for Pivotal Greenplum Command Center are provided in the latest Pivotal Greenplum Command Center Documentation.

Greenplum Command Center Resolved Issues

The following table lists issues that were resolved in Pivotal Greenplum Command Center 3.x.

Greenplum Command Center Known Issues

This section lists the known issues in Pivotal Greenplum Command Center 3.x.

About Pivotal Greenplum Workload Manager

Greenplum Workload Manager services collect query execution data and real-time system statistics on each segment host. The Workload Manager rules engine allows you to create rules that specify criteria that trigger an action, for example terminating a query that runs longer than a specified time or consumes too many resources on a segment host.

Real-time query performance can be viewed in the Workload Manager gptop curses-based GUI.

Enhancements and Changes in Greenplum Workload Manager 1.8.0

Compatibility with Greenplum Database 4.3.13

The view created using the SQL script file gp_session_state.sql that ships with Greenplum Database 4.3.13.0 is not compatible with Greenplum Workload Manager 1.7.2 and earlier. This version provides the compatibility.

gp_segment_configuration used for WLM Installation

Previously, multiple methods were used to access a server’s hostname during installation. Customers that had inconsistent hostname configurations were experiencing installation issues. To eliminate any potential source of hostname error, GP-WLM now uses gp_segment_configuration as the source of truth for hostnames. In this release, the most consequential occurrences of hostname have been consolidated; the remaining ones will be removed in upcoming releases.

gp_wlm_records can now be sorted and filtered by time and displayed in user’s timezone

The time column of the gp_wlm_records table is now a timestamp with timezone (timestampz) type. As a result, users can now sort and filter rows using time functions and operators. In addition, users can view time in the timezone set in their sessions. For example, you can set the timezone in a psql session with a command such as SET TIME ZONE ‘PST8PDT’ to view the time column in PDT timezone.

See Recreate the gp_wlm_records External Table for information about upgrading the gp_wlm_records table when upgrading to GP-WLM 1.8.0.

Removed repeated data from gp_wlm_records context column

The context column of the gp_wlm_records table contained information that was already available in other columns. These data are now removed from the context column, making it easier for users to see data they have added using the including clause of their rules.

Enhanced installation error messages

Some of the error messages shown during installation have been improved to help the user identify the cause of the error and accordingly take action to resolve the issue. For example, if a user attempts to install Workload Manager on a segment, instead of the master host, they will receive the following message: “WLM must be installed on the GPDB master host. Please retry installing on GPDB master host.” Another example is if the Greenplum cluster is not running at the time of WLM installation. The user will then be presented the message: “Greenplum cluster is not started. Please start the cluster and try installing WLM again.”

Terminology change

In this Greenplum Workload Manager release the term datum is replaced by the term metric.

Enhancements and Changes in Greenplum Workload Manager 1.7.3

The following are changes in Greenplum Workload Manager 1.7.3.

Compatibility with Greenplum Database 4.3.13

The view created using the SQL script file gp_session_state.sql that ships with Greenplum Database 4.3.13.0 is not compatible with Greenplum Workload Manager 1.7.2 and earlier. This version provides the compatibility.

host:pg_cancel_backend() now acts on subsequent queries in the same session

The rule action host:pg_cancel_backend now cancels queries that start after it has canceled a query that was running in the same session. Previously, this action only acted on the first offending query in a session and not on the subsequent queries in that same session. For example, the following rule would cancel only the first query that has exceeded 10 seconds and not the other queries that follow it.

rule add cancel_long_query host:pg_cancel_backend() when session_id:host:pid:runtime > 10

host:pg_cancel_backend() no longer tries to cancel queries on idle session processes

host:pg_cancel_backend() now checks if a session process has a query running and attempts to cancel only if the process is active with processing a query. Previously, host:pg_cancel_backend() attempted to cancel queries on sessions that did not have queries running. Consequently, gp_wlm_events should no longer have entries for host:pg_cancel_backend action if matching pids are idle and not running a query.

Enhancements and Changes in Greenplum Workload Manager 1.7.2

The following are changes in Greenplum Workload Manager 1.7.2.

Timezone aware dates and times

The timestamps in the gp_wlm_events table now display using the timezone set in the database session. Previously, they displayed in UTC regardless of the timezone setting. In psql, use the SHOW TIME ZONE; and SET TIME ZONE '<your_timezone>'; commands to see and set the timezone.

Reduced frequency of transaction ID (XID) creation

Workload Manager frequently queries the Greenplum database to collect statistics from the catalog tables. To reduce the need for frequent VACUUM execution and to avoid transaction ID wraparound, certain Workload Manager queries now execute within explicit BEGIN/END transactions.

Enhancements and Changes in Greenplum Workload Manager 1.7.0

The following are enhancements and changes in Greenplum Workload Manager 1.7.0.

SUSE Linux 11

Support is added for running Greenplum Workload Manager on SUSE Linux 11.

The Greenplum Command Center installer now includes separate installers for RHEL and SUSE platforms. The installer files have names in the format gp-wlm-<version>-<platform>.bin, where <version> is the Workload Manager release number and <platform> is the identifier for the Linux distribution and architecture.

Changes to gp_wlm_events View

The gp_wlm_events view is changed to include additional fields so that a base set of datums is available in each event row. Additional datums referenced in the rule expression are added to the view’s context column.

See Querying Workload Manager Event Data for the new gp_wlm_events structure and examples.

After you upgrade Workload Manager, you must run the manage-event-tables.sh script to recreate the external tables and gp_wlm_events view with the new structure. See Recreate the gp_wlm_events External Tables and View for instructions.

Enhancements and Changes in Greenplum Workload Manager 1.6.0

The following are enhancements and changes in Greenplum Workload Manager 1.6.0.

Improved Hostname Handling

During startup, the runtime framework detects and ignores duplicate hostnames. Duplicate hostnames are hostnames that resolve to the same machine.

Improved Response to Cancel Query

The amount of time Workload Manager takes to respond to a query cancellation request has been reduced to a minimum so that the request is delivered to Greenplum Database without delay.

Enhancements and Changes in Greenplum Workload Manager 1.5.0

The following are enhancements and changes in Greenplum Workload Manager 1.5.0.

Removed Option to Install Workload Manager with gpcmdr Command

The Greenplum Command Center 2.4.0 gpcmdr --setup utility no longer offers to install Greenplum Workload Manager. Workload Manager must be installed using its installer, gp-wlm-<version>-<platform>.bin, which is located in the Command Center installation directory. See Installing Greenplum Workload Manager for installation instructions.

Publishing Connections and Sessions

By default, Workload Manager now publishes information about idle Greenplum Database sessions. An idle session represents a client connection without an active or queued query.

To create a rule that is triggered by idle transactions, session_id:host:pid:current_query = "<IDLE>" in the when clause. For example, the following message records a message when an idle psql session is detected.

gpdb_record(message="Idle PSQL session") 
when host:pid:current_query = "<IDLE>" and host:pid:name = "psql"

In Workload Manager 1.0 through 1.4, information about idle sessions was never published, so they could not be detected with a rule. With 1.5.0, idle sessions are published by default.

You can revert to the previous behavior by configuring the following settings to ‘false’.

In addition to the new publish_idle_sessions settings in the table above, the following new configuration setting is available in the gp-wlm CLI.

See Configuring Workload Manager Components in the Greenplum Workload Manager User Guide for information about setting configuration values.

Including Additional Datums in Action Scope

Rules can now be created or modified to include datums in the action scope in addition to the datums that trigger the rule action. Previously, only values of datums present in the conditional expression that triggered the rule were captured when the rule was triggered.

In Workload Manager 1.5.0, additional datums specified using the including keyword are also captured. The context columns in the gp_wlm_record table or gp_wlm_events view will contain values for datums that triggered the rules as well as values for datums specified using the including keyword.

See Adding Rules in the Greenplum Workload Manager User Guide for information about this new feature.

Application Name Field is Set for Workload Manager GPDB Sessions

Greenplum Database sessions initiated by Workload Manager components are now configured to set the application_name field to 'gp-wlm’. This field is available in the pg_stat_activity table.

Enhancements in Greenplum Workload Manager 1.4.0

The following are enhancements and changes in Greenplum Workload Manager release 1.4.0:

New Features and Improvements

• A host:pg_cancel_backend action is added. This action calls the PostgreSQL pg_cancel_backend() function, which sends a SIGINT signal to the backend process, cancelling the current query. This differs from the pg_terminate_backend() function, which sends a SIGTERM signal and terminates the session. host:pg_cancel_backend events are logged to the wlm_event_log
• A new set of datums is added to provide Greenplum segment virtual memory (vmem) statics.
• The timing values that determine how frequently agents publish datums and rules are evaluated have been changed from integer to float values, allowing sub-second times to be specified.
• A new configuration manager allows viewing, describing, and modifying user-settable configuration values for Workload Manager components. In release 1.4.0, the configuration manager supports viewing, describing, and setting various configuration values for Workload Manager.

Fixes

• Fixed a rare bug where some queries cannot be ruled upon if the the session id of the query is not present in the list_backend_priorities() recordset.

• In certain environments, environment variables were not being set correctly.

Greenplum Workload Manager Installation and Upgrade

To install Greenplum Workload Manager, run the Workload Manager installer found in the Greenplum Command Center installation directory. See Installing Greenplum Workload Manager in the Greenplum Workload Manager documentation for command syntax and usage.

Recreate the gp_wlm_records External Table

In Greenplum Workload Manager release 1.8.0, the type of the time column of the gp_wlm_records external table changed from text to timestampz. If you use gp_wlm_records, run the following command to drop the external table before installing or upgrading Workload Manager:

$ psql -d postgres -c 'drop external table gp_wlm_records;'

After the table has been dropped, Workload Manager will automatically recreate the gp_wlm_records table during installation or upgrade.

Recreate the gp_wlm_events External Tables and View

In Greenplum Workload Manager release 1.7.0 the schema of the gp_wlm_events view changed. If you use gp_wlm_events, run the following script to recreate the view with the correct schema:

$ <INSTALL_DIR>/gp-wlm/bin/manage-event-tables.sh --create --dbname=<database-name>

This command re-creates the gp_wlm_events external tables and views in the designated database. The old CSV event files from the previous installation, if any, remain on disk.

To see the old CSV event files, run this command, with a hostfile containing the names of all segment hosts. See gpssh in the Greenplum Database Utility Guide for instructions to create a host file.

$ gpssh -f <hostfile> -e "find <INSTALL_DIR>/gp-wlm/ -name 'events*.csv' -exec ls {} \;"

To delete the old CSV event files, run this command:

$ gpssh -f <hostfile> -e "find <INSTALL_DIR>/gp-wlm/ -name 'events*.csv' -exec rm {} \;"

Greenplum Workload Manager Known Issues

This section lists the known issues in Pivotal Greenplum Workload Manager. A work-around is provided where applicable.

getopt: unrecognized option 'func-file=<INSTALL_DIR>/gp-wlm-data/.scratch/installer/installer.functions'