2021

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Release notes for AnalyticDB for PostgreSQL (elastic storage mode) in 2021.

To update your instance to the latest minor engine version, see Update the minor engine version.

December 6, 2021 (V6.3.6.1)

New features

Materialized view: query rewrite

Query rewrite is now supported for materialized views, improving performance for JOIN operations, aggregate functions, subqueries, common table expressions (CTEs), and high-concurrency SQL statements.

Real-time materialized views are now supported for partitioned tables.

References:

Partitioned table: conflict handling

INSERT ON CONFLICT and COPY ON CONFLICT statements are now supported for partitioned tables.

References:

pg_cron V1.4: enhanced scheduled tasks

The pg_cron extension is updated to V1.4 with the following additions:

  • Scheduled tasks can run across databases.

  • Existing scheduled tasks can be modified.

  • Task names can be specified.

  • The cron.job_run_details table records execution details for each scheduled task run.

Reference: Use the pg_cron extension to configure scheduled tasks

Data reads during compute node specification changes

Before V6.3.6.1, all tables were unavailable (neither readable nor writable) during compute node specification changes, because data was redistributed across all tables. Starting from V6.3.6.1, all tables remain readable during the process. Only tables actively undergoing data redistribution are temporarily not writable.

Fixed issues

Issue

Unexpected gang size error errors in specific scenarios

Frequent FATAL: reader could not find writer proc entry errors in specific scenarios

Laser engine left join errors in specific scenarios

Data restoration failures for Basic Edition instances caused by an invalid synchronous_standby_names parameter

October 13, 2021 (V6.3.5.2)

New features

Auto-merge

Auto-merge automatically sorts and consolidates data in the background. It periodically checks table data, sorts newly inserted unordered data, and merges it with the existing ordered data.

Auto-merge supports only append-optimized (AO) tables that are configured with sort keys.

Reference: Auto-merge

Automatic closing of idle connections

Connections that have been idle for 6 hours are automatically closed.

Optimizations

Sorting acceleration

Sorting acceleration now applies when data is updated.

Reference: Configure sorting acceleration

Laser engine improvements

  • Improved Laser engine execution performance on Master nodes.

  • Improved ORDER BY performance on large datasets.

  • Improved COUNT DISTINCT performance.

Reference: Use the Laser computing engine

Increased maximum user connections

The maximum number of user connections is increased for the following instance specifications:

Instance specification

Previous limit

New limit

2 cores, 16 GB

300

550

4 cores, 32 GB

300

750

8 cores, 64 GB

400

950

AUTO VACUUM and AUTO ANALYZE

Multi-Master architecture AnalyticDB for PostgreSQL instances support AUTO VACUUM and AUTO ANALYZE.

Reference: Limits

Real-time materialized view enhancements

  • INSERT ON CONFLICT DO UPDATE and COPY ON CONFLICT DO UPDATE statements are now supported.

  • Fixed incorrect refresh of real-time materialized views in Multi-Master scenarios.

  • Replicated tables are now supported.

  • UPSERT clauses are now supported.

Reference: Real-time materialized views

PL/Java disabled by default

PL/Java is now disabled by default.

Reference: Create and use PL/Java UDFs

Fixed issues

Issue

Laser engine: pointer exceptions in specific hash join scenarios

Laser engine: errors in specific hash left join, hash right join, or hash full join scenarios

Laser engine: bitmap index scans on append-optimized column-oriented tables taking excessive time

Laser engine: execution failures when a large number of partitioned tables are involved

Column names containing totalrows or totaldeadrows were rejected

INT96-to-TIMESTAMP conversion failures in Parquet-formatted Object Storage Service (OSS) foreign tables

Archiving exceptions after a primary/secondary switchover caused by missing archiving programs or Python module import failures

Memory leaks when data is accessed or source files are modified while OSS foreign tables are being scanned

July 13, 2021 (V6.3.4.0)

New features

Laser engine enabled by default

The Laser computing engine is now enabled by default.

Reference: Use the Laser computing engine

Parallel query enabled by default

Parallel query for individual tables is now enabled by default.

Reference: Configure parallel query

Sorting acceleration

Sorting acceleration pushes SORT, AGG, and JOIN operators down to the storage layer, accelerating queries based on the physical order of data. Run SORT <tablename> to sort the data of a table and activate storage-layer acceleration for that table.

Reference: Configure sorting acceleration

Minor version query via GUC parameter

Use the following Global User Configuration (GUC) parameter to query the minor engine version of your instance:

show adbpg_version;

Reference: View the minor engine version

Backup and restore

Multi-Master architecture AnalyticDB for PostgreSQL supports the backup and restore feature.

Optimizations

Real-time materialized view performance

Real-time materialized view performance is improved. The MAX and MIN aggregate functions can now be used in DELETE and UPDATE statements. CTEs can now be used in change statements executed on base tables.

Reference: Real-time materialized views

Fixed issues

Issue

Distributed transaction performance enhancement for Multi-Master instances

For Multi-Master instances, each Master node no longer needs to request a distributed transaction ID from the GTM when executing distributed transactions. Instead, it can generate the ID locally. This eliminates the GTM single-point bottleneck under high concurrency, improving distributed transaction capability, especially for high-concurrency data import scenarios.

None

Panic errors in the checkpoint process on the secondary server after truncating an AO table multiple times within a transaction and then aborting the transaction

Fixed an issue where deadlocks could not be detected after more than two distributed transactions were initiated within the same session on a Secondary Master of a Multi-Master instance.

May 28, 2021

New features

auto-vacuum

auto-vacuum automatically runs VACUUM on tables. By default, it triggers when more than 50% of a table's rows have been deleted, removing dead rows to keep query performance stable. auto-vacuum checks for tables that have a large number of INSERT, UPDATE, or DELETE operations.

For Multi-Master instances, only changes on the primary Master can currently be tracked. Changes on secondary Masters do not trigger AUTO VACUUM.

Reference: Configure scheduled maintenance tasks to clear junk data

auto-analyze

auto-analyze automatically runs ANALYZE on tables that have a significant number of INSERT, UPDATE, or DELETE operations. By default, it triggers when more than 10% of a table's rows are affected, keeping table statistics up to date for accurate query plans.

For Multi-Master instances, only changes on the primary Master can currently be tracked. Changes on secondary Masters do not trigger AUTO ANALYZE.

Reference: Use the ANALYZE statement to collect statistics on AnalyticDB for PostgreSQL

BRIN index (Block Range Index)

BRIN indexes are now supported for compressed AO tables. They can be used to query large-range data from an ordered table or filter out data blocks that are not needed to reduce I/O. Compared to B-tree indexes on large datasets, BRIN indexes provide similar or superior performance while requiring significantly less storage and are faster to build.

Reference: Manage indexes

Parallel query (Preview)

The rds_segment_expansion_coeff parameter enables session-level parallel query. It specifies a multiplier of cores allocated to a single query. The default value is 1 (INTEGER type).

This parameter improves performance linearly for compute-intensive queries that run longer than 3 seconds when queries per second (QPS) is low. Effective scenarios include aggregate queries on individual tables (such as TPC-H Q1 and TPC-H Q6) and joins between large and small tables. It provides limited improvement for I/O-intensive queries and high disk usage scenarios, and may reduce performance for network-intensive queries.

Real-time materialized view (Preview)

Real-time materialized views are now available. Unlike standard materialized views, they stay up to date automatically when the underlying data changes—no manual REFRESH statements needed.

Reference: Real-time materialized views

Optimizations

Instance endpoint enhancements

  • DDL operations can now be performed between the BEGIN and ROLLBACK/COMMIT transaction blocks via instance endpoints.

  • TEMP TABLE and TEMP VIEW operations are now supported for session-level queries via instance endpoints.