Pivotal Greenplum 6.4 Release Notes

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Pivotal Greenplum 6.4 Release Notes

This document contains pertinent release information about Pivotal Greenplum Database 6.4 releases. For previous versions of the release notes for Greenplum Database, go to Pivotal Greenplum Database Documentation. For information about Greenplum Database end of life, see Pivotal Greenplum Database end of life policy.

Pivotal Greenplum 6 software is available for download from the Pivotal Greenplum page on Pivotal Network.

Pivotal Greenplum 6 is based on the open source Greenplum Database project code.

Important: Pivotal Support does not provide support for open source versions of Greenplum Database. Only Pivotal Greenplum Database is supported by Pivotal Support.

Release 6.4.0

Release Date: 2020-02-11

Pivotal Greenplum 6.4.0 is a maintenance release that includes changed features and resolves several issues.

Changed Features

Greenplum Database 6.4.0 includes these changed features:

  • DISCARD ALL is not supported. The command returns a message that states that the command is not supported and to consider alternatives such as DEALLOCATE ALL or DISCARD TEMP. See DISCARD.
  • Greenplum Database resource groups support automatic query termination when resource group global shared memory is enabled. For resource groups that use global shared memory, Greenplum Database gracefully cancels running queries that are managed by those resource groups when the queries consume a large portion of the global shared memory. At this point, the queries would have already consumed available resource group slot memory and group shared memory. Greenplum Database cancels queries in order of memory used, from highest to lowest until the percentage of utilized global shared memory is below the percentage specified by the server configuration parameter runaway_detector_activation_percent.

    Global shared memory is enabled for resource groups that are configured to use the vmtracker memory auditor, such as admin_group and default_group when the sum of the MEMORY_LIMIT attribute values configured for all resource groups is less than 100. If resource groups are not configured to use global shared memory pool, the resource group automatic query termination feature is not enabled.

    For information about resource groups, see Using Resource Groups.

  • Greenplum Database supports creating the standby master or mirror segment instances on hosts that are in a different subnet from the master and primary segment instance hosts. Mirror segment instances can also be moved to hosts that are in a different subnet.

Resolved Issues

Pivotal Greenplum 6.4.0 resolves these issues:

30209, 170762049 - gpaddmirrors
The gpaddmirrors utility failed to add mirror segments to a Greenplum Database system, when the mirror segments are in a different subnet from the primary segments. This issue is resolved. Now Greenplum Database supports mirror segments in a different subnet from the primary segments.
30266 - Vacuum
The vacuum workflow changed in Greenplum Database 6 to dispatch once per auxiliary table in addition to the dispatch for the main table. This could cause performance problems and permission verification failures on auxiliary tables. This is fixed. The VACUUM command again dispatches once per segment.
30282 - Resource Management
For some queries managed by Greenplum Database resource groups, the query failed due to an out of memory condition. This caused a segment failure and other issues. This issue is resolved. Resource groups have been enhanced to handle queries that consume a large amount of memory. See Changed Features.
30299 - Server: Execution
For some queries against a partitioned table with multiple column indexes that perform a dynamic index scan, Greenplum Database generated a SIGSEGV. The error occurred when Greenplum Database did not correctly manage dynamic index scan pointer memory. This issue is resolved.
30325 - Query Optimizer
For some queries that reference a view that is defined with a CTE (common table expression) query, and the main query also contains a predicate that is a subquery that references the view, GPORCA returns an error that states could not open temporary file. The error was caused by incorrect predicate pushdown during preprocessing. This issue is resolved.
30359 - Server: Segment Mirroring
A panic occurred during crash recovery for a mirror when replaying WAL records for a transaction that created an append-optimized table, truncated the table, and then aborted the transaction. This issue is resolved.
30354 - DISCARD
DISCARD TEMP might not drop temporary tables on segment instances. This issue is resolved.
30360 - Server: Security
Greenplum Database incorrectly logged the message time constraints added on superuser role every time a superuser role was checked. Now the message is logged only when time constraints are added to a superuser role.
30366 - Server: Execution
Using GRANT commands on partitioned tables across segments would cause the system to PANIC due to alterations in the cached plan. This issue has been resolved.
30371 - Server: Execution
The to_timestamp() function did not return an error for an out of range value. For example, select to_timestamp('20200340123456','YYYYMMDDHH24MISS'); returned a valid date and time 2020-04-09 12:34:56-07. This issue is resolved. Now the function returns an error.
30387 - Server: DML
After completing the execution of a user-defined function that changed the value of a server configuration parameter, Greenplum Database restored the original parameter value on the query dispatcher, but did not synchronize and restore the value to the query executors. This issue is resolved.
170787232 - Server: Query Dispatcher
A Query Dispatcher (QD) would run into local deadlock for some prepared statements that execute an UPDATE or DELETE command. This issue has been fixed by taking into consideration the server configuration parameter gp_enable_global_deadlock_detector.

Upgrading to Greenplum 6.4.0

Note: Greenplum 6 does not support direct upgrades from Greenplum 4 or Greenplum 5 releases, or from earlier Greenplum 6 Beta releases.

See Upgrading from an Earlier Greenplum 6 Release to upgrade your existing Greenplum 6.x software to Greenplum 6.4.0.

Deprecated Features

Deprecated features will be removed in a future major release of Greenplum Database. Pivotal Greenplum 6.x deprecates:

  • The analzyedb option --skip_root_stats (deprecated since 6.2).

    If the option is specified, a warning is issued stating that the option will be ignored.

  • The server configuration parameter gp_statistics_use_fkeys (deprecated since 6.2).
  • The following PXF configuration properties (deprecated since 6.2):
    • The PXF_USER_IMPERSONATION, PXF_PRINCIPAL, and PXF_KEYTAB settings in the pxf-env.sh file. You can use the pxf-site.xml file to configure Kerberos and impersonation settings for your new Hadoop server configurations.
    • The pxf.impersonation.jdbc property setting in the jdbc-site.xml file. You can use the pxf.service.user.impersonation property to configure user impersonation for a new JDBC server configuration.
  • The server configuration parameter gp_ignore_error_table (deprecated since 6.0).

    To avoid a Greenplum Database syntax error, set the value of this parameter to true when you run applications that execute CREATE EXTERNAL TABLE or COPY commands that include the now removed Greenplum Database 4.3.x INTO ERROR TABLE clause.

  • Specifying => as an operator name in the CREATE OPERATOR command (deprecated since 6.0).
  • The Greenplum external table C API (deprecated since 6.0).

    Any developers using this API are encouraged to use the new Foreign Data Wrapper API in its place.

  • Commas placed between a SUBPARTITION TEMPLATE clause and its corresponding SUBPARTITION BY clause, and between consecutive SUBPARTITION BY clauses in a CREATE TABLE command (deprecated since 6.0).

    Using this undocumented syntax will generate a deprecation warning message.

  • The timestamp format YYYYMMDDHH24MISS (deprecated since 6.0).

    This format could not be parsed unambiguously in previous Greenplum Database releases, and is not supported in PostgreSQL 9.4.

  • The createlang and droplang utilities (deprecated since 6.0).
  • The pg_resqueue_status system view (deprecated since 6.0).

    Use the gp_toolkit.gp_resqueue_status view instead.

  • The GLOBAL and LOCAL modifiers when creating a temporary table with the CREATE TABLE and CREATE TABLE AS commands (deprecated since 6.0).

    These keywords are present for SQL standard compatibility, but have no effect in Greenplum Database.

  • The Greenplum Platform Extension Framework (PXF) HDFS profile names for the Text, Avro, JSON, Parquet, and SequenceFile data formats (deprecated since 5.16).

    Refer to Connectors, Data Formats, and Profiles in the PXF Hadoop documentation for more information.

  • Using WITH OIDS or oids=TRUE to assign an OID system column when creating or altering a table (deprecated since 6.0).
  • Allowing superusers to specify the SQL_ASCII encoding regardless of the locale settings (deprecated since 6.0).

    This choice may result in misbehavior of character-string functions when data that is not encoding-compatible with the locale is stored in the database.

  • The @@@ text search operator (deprecated since 6.0).

    This operator is currently a synonym for the @@ operator.

  • The unparenthesized syntax for option lists in the VACUUM command (deprecated since 6.0).

    This syntax requires that the options to the command be specified in a specific order.

  • The plain pgbouncer authentication type (auth_type = plain) (deprecated since 4.x).

Migrating Data to Greenplum 6

Note: Greenplum 6 does not support direct upgrades from Greenplum 4 or Greenplum 5 releases, or from earlier Greenplum 6 Beta releases.

See Migrating Data from Greenplum 4.3 or 5 for guidelines and considerations for migrating existing Greenplum data to Greenplum 6, using standard backup and restore procedures.

Known Issues and Limitations

Pivotal Greenplum 6 has these limitations:

  • Upgrading a Greenplum Database 4 or 5 release, or Greenplum 6 Beta release, to Pivotal Greenplum 6 is not supported.
  • MADlib, GPText, and PostGIS are not yet provided for installation on Ubuntu systems.
  • Greenplum 6 is not supported for installation on DCA systems.
  • Greenplum for Kubernetes is not yet provided with this release.

The following table lists key known issues in Pivotal Greenplum 6.x.

Table 1. Key Known Issues in Pivotal Greenplum 6.x
Issue Category Description
10216 ALTER TABLE, ALTER DOMAIN In some cases, heap table data is lost when performing concurrent ALTER TABLE or ALTER DOMAIN commands where one command alters a table column and the other rewrites or redistributes the table data. For example, performing concurrent ALTER TABLE commands where one command changes a column data type from int to text might cause data loss. This issue might also occur when altering a table column during the data distribution phase of a Greenplum system expansion. Greenplum Database did not correctly capture the current state of the table during command execution.

This issue is resolved in Pivotal Greenplum 6.9.0.

N/A Metrics collector Setting the gpcc_enable_query_profiling configuration parameter to on may cause Greenplum Database to crash. This affects Greenplum Database versions 6.3, 6.4, and 6.5.

Workaround: Install Greenplum Command Center 6.2.0 and upgrade the metrics_collector extension with the gppkg package included with Greenplum Command Center 6.2.0.

N/A PXF Starting in 6.x, Greenplum does not bundle cURL and instead loads the system-provided library. PXF requires cURL version 7.29.0 or newer. The officially-supported cURL for the CentOS 6.x and Red Hat Enterprise Linux 6.x operating systems is version 7.19.*. Greenplum Database 6 does not support running PXF on CentOS 6.x or RHEL 6.x due to this limitation.

Workaround: Upgrade the operating system of your Greenplum Database 6 hosts to CentOS 7+ or RHEL 7+, which provides a cURL version suitable to run PXF.

N/A Logging In some cases, it is safe to ignore certain FATAL messages that Greenplum Database writes to the logs:
  • The Greenplum Database master or standby master host, or a primary or mirror segment, may log the FATAL message the database system is starting up when the instance is in a startup phase and it is not ready to accept a connection.
  • The Greenplum Database master or primary may log the FATAL message the database system is shutting down when Greenplum attempts to open a connection while the instance is in shutdown mode.
29703 Loading Data from External Tables Due to limitations in the Greenplum Database external table framework, Greenplum Database cannot log the following types of errors that it encounters while loading data:
  • data type parsing errors
  • unexpected value type errors
  • data type conversion errors
  • errors returned by native and user-defined functions
LOG ERRORS returns error information for data exceptions only. When it encounters a parsing error, Greenplum terminates the load job, but it cannot log and propagate the error back to the user via gp_read_error_log().

Workaround: Clean the input data before loading it into Greenplum Database.

30522 Logging Greenplum Database may write a FATAL message to the standby master or mirror log stating that the database system is in recovery mode when the instance is synchronizing with the master and Greenplum attempts to contact it before the operation completes. Ignore these messages and use gpstate -f output to determine if the standby successfully synchronized with the Greenplum master; the command returns Sync state: sync if it is synchronized.
170824967 gpfidsts For Greenplum Database 6.x, a command that accesses an external table that uses the gpfdists protocol fails if the external table does not use an IP address when specifying a host system in the LOCATION clause of the external table definition.
n/a Materialized Views By default, certain gp_toolkit views do not display data for materialized views. If you want to include this information in gp_toolkit view output, you must redefine a gp_toolkit internal view as described in Including Data for Materialized Views.
168689202 PXF PXF fails to run any query on Java 11 that specifies a Hive* profile due to this Hive known issue: ClassCastException when initializing HiveMetaStoreClient on JDK10 or newer.

Workaround: Run PXF on Java 8 or use the PXF JDBC Connector to access Hive.

168957894 PXF The PXF Hive Connector does not support using the Hive* profiles to access Hive transactional tables.

Workaround: Use the PXF JDBC Connector to access Hive.

169200795 Greenplum Stream Server When loading Kafka data into Greenplum Database in UPDATE and MERGE modes, GPSS requires that a MAPPING exist for each column name identified in the MATCH_COLUMNS and UPDATE_COLUMNS lists.
170202002 Greenplum-Kafka Integration Updating the METADATA:SCHEMA property and restarting a previously-run load job could cause gpkafka to re-read Kafka messages published to the topic, and load duplicate messages into Greenplum Database.
168548176 gpbackup When using gpbackup to back up a Greenplum Database 5.7.1 or earlier 5.x release with resource groups enabled, gpbackup returns a column not found error for t6.value AS memoryauditor.
164791118 PL/R PL/R cannot be installed using the deprecated createlang utility, and displays the error:
createlang: language installation failed: ERROR:
no schema has been selected to create in
Workaround: Use CREATE EXTENSION to install PL/R, as described in the documentation.
30437 JDBC Driver JDBC cached query plans do not store the partition selector parameter that is required for performing partition elimination. If you create a JDBC prepared statement that operates against a partitioned table, partition elimination is performed the first 5 times the query is executed. After that point, the JDBC driver may choose to cache the query plan, in which case partition elimination is no longer performed and the query may suffer from extremely degraded performance.

Workaround: Use the DataDirect JDBC driver version (F000450.U000214) or later, introduced in Greenplum 6.1, and set the prepareThreshold connection parameter to a very large value. For example: jdbc:Pivotal:greenplum://<ip>:<port>;DatabaseName=<name>;prepareThreshold=1000000000 See PrepareThreshold in the DataDirect documentation.

9460 CREATE UNIQUE INDEX When you create a unique index on a partitioned table, Greenplum Database does not check to ensure that the index contains the table partition keys, which are required to enforce uniqueness. Workaround: To avoid duplicate rows, manually specify partition keys when executing CREATE UNIQUE INDEX on a partitioned table.
N/A Greenplum Client/Load Tools on Windows The Greenplum Database client and load tools on Windows have not been tested with Active Directory Kerberos authentication.

Differences Compared to Open Source Greenplum Database

Pivotal Greenplum 6.x includes all of the functionality in the open source Greenplum Database project and adds:
  • Product packaging and installation script
  • Support for QuickLZ compression. QuickLZ compression is not provided in the open source version of Greenplum Database due to licensing restrictions.
  • Support for data connectors:
    • Greenplum-Spark Connector
    • Greenplum-Informatica Connector
    • Greenplum-Kafka Integration
    • Greenplum Stream Server
  • Data Direct ODBC/JDBC Drivers
  • gpcopy utility for copying or migrating objects between Greenplum systems
  • Support for managing Greenplum Database using Pivotal Greenplum Command Center
  • Support for full text search and text analysis using Pivotal GPText
  • Greenplum backup plugin for DD Boost
  • Backup/restore storage plugin API (Beta)