VMware Tanzu Greenplum 6.13 Release Notes

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VMware Tanzu Greenplum 6.13 Release Notes

This document contains pertinent release information about VMware Tanzu Greenplum Database 6.13 releases. For previous versions of the release notes for Greenplum Database, go to VMware Tanzu Greenplum Database Documentation. For information about Greenplum Database end of life, see VMware Tanzu Greenplum Database end of life policy.

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

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

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

Release 6.13.0

Release Date: 2020-12-18

VMware Tanzu Greenplum 6.13.0 is a minor release that includes changed features and resolves several issues.

Features

Greenplum Database 6.13.0 includes these new and changed features:

  • This release introduces the new VMware Tanzu Greenplum Connector for Apache NiFi 1.0.0. The Connector provides a fast and simple, UI-based way to build data ingestion pipelines for Greenplum Database, code-free. The Connector is available as a separate download from VMware Tanzu Network. Refer to the VMware Tanzu Greenplum Connector for Apache NiFi documentation for installation, configuration, and usage information for the Connector.
  • Greenplum Streaming Server (GPSS) version 1.5.0 is included, which introduces many new and changed features and bug fixes. Refer to the GPSS Release Notes for more information on release content and to access the GPSS documentation.
    Note: If you have previously used GPSS in your Greenplum 6.x installation, you are required to perform upgrade actions as described in Upgrading the Streaming Server.
  • The distribution includes the advanced_password_check contrib module; you can use this module to specify password string quality policies for Greenplum Database. Refer to the advanced_password_check module documentation for more information.
  • The Greenplum Database Query Optimizer exposes a new server configuration parameter to enable index-only scans. These scans answer queries from an index alone without requiring any heap access. This configuration parameter is named optimizer_enable_indexonlyscan, and is enabled by default.

Resolved Issues

VMware Tanzu Greenplum 6.13.0 resolves these issues:

30994 - Cluster Management
Resolved an issue where gpstart could fail with an non-descript error when a segment host was unreachable during Greenplum Database initialization. gpstart now continues the startup process even if some cluster hosts are unreachable.
31028 - Cluster Management
When using gpconfig -s client_min_messages to set the client messaging level (for example "notice" or "warning"), the output showed "error" instead of the level configured by the user. This issue has been resolved.
10720 - Planner
Resolved a problem that could cause the Postgres Planner to crash or return incorrect results if a query used a grouping expression (rather than a column name) along with other ungrouped targets that referenced the group key.
10961 - Locking
Improved the locking behavior to avoid deadlocks that can occur when creating multiple indexes on an Append-Only table.
30951 - Query Optimizer
Resolves an issue where a query performed on a serial-type column of a replicated Greenplum table (created DISTRIBUTED REPLICATED) failed to return a consistent value on all segments.
30976 - Server: Execution
In some cases, Greenplum Database returned incorrect results when it ran certain system functions in an EntryDb (a special query executor (QE) that runs on the master instance). This issue is resolved; Greenplum now returns the error "This query is not currently supported by GPDB." when it encounters a function invocation that it does not support.
31011 - Server: Execution
Resolved a problem that could cause a segfault when spilling hash tables to disk. In Greenplum 6 this problem was reported with a materialized view query that produced a HashAggregate plan.
31073 - Segment Mirroring
Resolves an issue where the kernel Recv-Q buffer filled up on a Greenplum mirror segment instance when the mirror sent statistics to the statistics collector, but the collector was not running because the mirror was not in hot standby mode.
31082 - Server: Execution
Resolved an issue where the planner generated an incorrect plan for some queries that included a merge join and dynamic partition elimination. The storage needed for the merge join key was incorrectly allocated on the inner side of the plan tree. This led to a SIGSEGV when executing the sort node of the inner side of the merge join. The problem was resolved by ensuring that only the nodes that need to use the join key are provisioned with the right amount of storage, leaving the rest of the plan tree intact.
31090 - Storage: Segment Mirroring
pg_rewind was updated to reduce the number of lstat operations it performs, in order to improve the performance of incremental recovery with a large number of data files.
173157638 - Cluster Management
When the user specified a valid port range using the gpaddmirrors -p option, gpaddmirrors would generate an error similar to error: Value of port offset supplied via -p option produces ports outside of the valid range. Mirror port base range must be between 6432 and 61000. This issue has been resolved.

Upgrading from Greenplum 6.x to Greenplum 6.13

Note: Greenplum 6 supports direct upgrades, using gpupgrade, from Greenplum 5.x releases to Greenplum 6.x. For more information, see the gpupgrade documentation. See also 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.

See Upgrading from an Earlier Greenplum 6 Release to upgrade your existing Greenplum 6.x software to Greenplum 6.13.0.

Deprecated Features

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

  • The gpsys1 utility.
  • 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 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.

  • 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 supports direct upgrades, using gpupgrade, from Greenplum 5.x releases to Greenplum 6.x. For more information, see the gpupgrade documentation.

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

VMware Tanzu Greenplum 6 has these limitations:

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

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

Table 1. Key Known Issues in VMware Tanzu Greenplum 6.x
Issue Category Description
31010 Query Optimizer A view created in Greenplum Database 5.28.3 or older that specified an external table in the FROM clause, and that was migrated to Greenplum Database 6.x, always falls back to the Postgres Planner when queried.

Workaround: If you migrated a view from Greenplum Database 5.28.3 or earlier, and the view specified an external table in the FROM clause, you must drop and recreate the view in Greenplum 6.x to ensure that the Query Optimizer is exercised when you query the view.

N/A Backup/Restore Restoring the Greenplum Database backup for a table fails in Greenplum 6 versions earlier than version 6.10 when a replicated table has an inheritance relationship to/from another table that was assigned via an ALTER TABLE ... INHERIT statement after table creation.
Workaround: Use the following SQL commands to determine if Greenplum Database includes any replicated tables that inherit from a parent table, or if there are replicated tables that are inherited by a child table:
SELECT inhrelid::regclass FROM pg_inherits,
  gp_distribution_policy dp
WHERE inhrelid=dp.localoid AND dp.policytype='r';
SELECT inhparent::regclass FROM pg_inherits,
  gp_distribution_policy dp
WHERE inhparent=dp.localoid AND dp.policytype='r';

If these queries return any tables, you may choose to run gprestore with the -–on-error-continue flag to not fail the entire restore when this issue is hit. Or, you can specify the list of tables returned by the queries to the -–exclude-table-file option to skip those tables during restore. You must recreate and repopulate the affected tables after restore.

N/A Spark Connector This version of Greenplum is not compatible with Greenplum-Spark Connector versions earlier than version 1.7.0, due to a change in how Greenplum handles distributed transaction IDs.
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.

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.

30594 Resource Management Resource queue-related statistics may be inaccurate in certain cases. VMware recommends that you use the resource group resource management scheme that is available in Greenplum 6.
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.
30537 Postgres Planner The Postgres Planner generates a very large query plan that causes out of memory issues for the following type of CTE (common table expression) query: the WITH clause of the CTE contains a partitioned table with a large number partitions, and the WITH reference is used in a subquery that joins another partitioned table.

Workaround: If possible, use the GPORCA query optimizer. With the server configuration parameter optimizer=on, Greenplum Database attempts to use GPORCA for query planning and optimization when possible and falls back to the Postgres Planner when GPORCA cannot be used. Also, the specified type of query might require a long time to complete.

170824967 gpfdists 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.
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.

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.
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

VMware Tanzu 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 Streaming Server
  • Data Direct ODBC/JDBC Drivers
  • gpcopy utility for copying or migrating objects between Greenplum systems
  • Support for managing Greenplum Database using VMware Tanzu Greenplum Command Center
  • Support for full text search and text analysis using VMware Tanzu GPText
  • Greenplum backup plugin for DD Boost
  • Backup/restore storage plugin API