2020

Category

Feature

Description

References

New feature

Partitioned table

The Merge Partitions feature is added to merge two partitioned tables.

• ALTER TABLE…MERGE PARTITION

• ALTER TABLE...MERGE SUBPARTITION

Compatibility with decoding in Oracle

Base64 decoding used in Oracle is supported. The BASE64_DECODE function can automatically identify an invalid encoded string and decode the first valid part of the string.

polar_enable_base64_decode

Date format

Dates in the YYYYMMDDHH24MISS format can be inserted or updated.

None

SYS.***_TAB_COLS view

The SYS.***_TAB_COLS view is supported. This view can be used to query columns of tables and views.

• ALL_TAB_COLS

• DBA_TAB_COLS

• USER_TAB_COLS

polar_utility plug-in

The polar_utility plug-in is added.

polar_utility

Stored procedure

Holdable refcursors can be returned by stored procedures.

None

DBMS_JOB package

The DBMS_JOB package is added. You can invoke the package or schedule it across databases by using a privileged account.

DBMS_JOB

Optimized feature

UTL_ENCODE

The UTL_ENCODE plug-in can be used by newly created standard users.

UTL_ENCODE

polar_agg plug-in

By default, the polar_agg plug-in is enabled.

None

fdw plug-in

The stability of the fdw plug-in is improved.

None

Fixed issue

The following issue is fixed: An error occurs when you execute SELECT INTO to query null values in a stored procedure.

The following issue is fixed: The constraints become invalid when an index scan is performed after you execute ALTER TABLE… EXCHANGE PARTITION.

Category

Feature

Description

References

New feature

DBLink

A database link can be established from a PolarDB for PostgreSQL (Compatible with Oracle) database to a self-managed PostgreSQL database hosted on an Elastic Compute Service (ECS) instance. This way, you can connect a PolarDB for PostgreSQL (Compatible with Oracle) database to a PostgreSQL database. You can also connect a PostgreSQL database to a PolarDB for Oracle database by using a database link in PostgreSQL. This way, the PolarDB for Oracle database and the PostgreSQL database can communicate with each other.

To create a database link in the console, choose Settings and Management > Databases on the cluster details page.

Create a database link from PolarDB for PostgreSQL (Compatible with Oracle) to PostgreSQL

Category

Feature

Description

References

New feature

ST_AsPNG

BYTEA-type images can be returned for vector pyramids. This feature can be used to visualize vector data.

ST_AsPNG

Raster data

The JPEG 2000 compression algorithm is supported. This algorithm is used to compress 16-bit raster data before the data is stored.

None

Optimized feature

st_dwithin

The ST_DWithin function is optimized to improve the performance of distance queries.

None

Fixed issue

The following issue is fixed: The intersection of trajectories on the t axis is improper.

The issues related to the memory topology indexes that are supported by Ganos are fixed.

Category

Feature

Description

Optimized feature

CreateDBLink

Database links can be created to connect PolarDB for PostgreSQL (Compatible with Oracle) databases to self-managed PostgreSQL databases that are hosted on ECS instances.

Category

Feature

Description

References

New feature

Compatibility

This minor version is compatible with PostgreSQL 11.9.

What is PolarDB for PostgreSQL (Compatible with Oracle)?

Failover

By default, the OnlinePromote feature is enabled. This feature reduces the amount of time that is consumed by a failover and improves cluster availability.

Automatic failover and manual failover

DBLink

Database links can be used to connect databases across PolarDB for PostgreSQL (Compatible with Oracle) clusters.

Database link overview

Fixed issue

The following issue is fixed: A node does not restart smoothly in some scenarios.

The following issue is fixed: In some scenarios, clusters do not respond due to OOM errors.

The following issue is fixed: In some scenarios, read-only nodes do not respond.

The following issue is fixed: An error occurs when the UTF-8 encoding format is converted into GBK after you run the client_encoding=gbk command.

The following issue is fixed: An error occurs when the first parameter of the NVL function is left empty.

Category

Feature

Description

References

New feature

DBLink

A database link can be created to connect a PolarDB for PostgreSQL (Compatible with Oracle) database to another PolarDB for PostgreSQL (Compatible with Oracle) database. This allows you to access data across PolarDB for PostgreSQL (Compatible with Oracle) databases.

To create a database link in the console, choose Settings and Management > Databases on the cluster details page.

Database link overview

Category

Feature

Description

New feature

CreateDBLink

This operation can be called to create a database link for a PolarDB for PostgreSQL (Compatible with Oracle) cluster.

DescribeDBLinks

This operation can be called to query database links for a PolarDB for PostgreSQL (Compatible with Oracle) cluster.

DeleteDBLink

This operation can be called to delete a database link for a PolarDB for PostgreSQL (Compatible with Oracle) cluster.

Category

Feature

Description

References

New feature

Audit log

Precompiled SQL statements in audit logs can be displayed as executable SQL statements.

None

Hash partitioning

The syntax that is used to create a specified number of hash partitioned tables is added.

CREATE TABLE ... PARTITION BY HASH

Partitioned table

The name of a partition or a subpartition can be specified when you query data of a specific partition.

Query a specified partition

HOST parameter

The HOST parameter is supported. This parameter is used to obtain the HOST value of a client.

None

Optimized feature

View

The query_id field is added to optimize the polar_stat_activity view.

None

Compatibility

The minor version is updated to 11.8. Several stability issues are fixed.

None

Fixed issue

The following issue is fixed: A semi-synchronization cannot time out.

The following issue is fixed: The CONNECT BY clause cannot be used together with the WITH clause.

Category

Feature

Description

References

New feature

Trajectory data type

GiST indexes are supported for trajectories. In addition, six operator families of different dimensions are provided to meet multi-dimensional analysis requirements.

None

The BoxND data type is supported. This data type is used to describe the bounding box of a spatio-temporal extent or a storage trajectory.

None

The following operators are supported: the && operator, the @> operator, and the <@ operator. These operators are used to compare the spatio-temporal relationships between two specified objects from various dimensions. The && operator is used to check whether the two specified objects intersect. The @> operator is used to check whether the left operand-specified object includes the right operand-specified object. The <@ operator is used to check whether the left operand-specified object is included in the right operand-specified object.

None

The ST_ndIntersects, ST_ndDWithin, ST_ndContains, and ST_ndWithin functions are supported to process trajectories.

• ST_{Z|T|2D|2DT|3D|3DT}Intersects

• ST_{2D|2DT|3D|3DT}DWithin

• ST_{T|2D|2DT|3D|3DT}Contains

• ST_{T|2D|2DT|3D|3DT}Within

Trajectory statistics can be collected. Scan costs can be estimated based on these trajectory statistics.

None

TrajGist indexes are supported. This provides an optimized indexing method.

None

ganos_update function

The ganos_update function is supported. You can run the select ganos_update() ; command to update all Ganos extensions to the latest version.

None

Optimized feature

Spatio-temporal range query

Spatio-temporal range queries are optimized. The query performance is improved by using optimized GiST index-based two-phase queries.

None

Vector pyramid

Source data from all the coordinate systems that provide spatial reference identifiers (SRIDs) is supported. The source data can be tiles that are based on the EPSG:3857 or EPSG:4326 coordinate reference system.

None

The pixelSize parameter is supported. This parameter is used to aggregate point data and reduce the number of tiles.

None

Fixed issue

The following issue is fixed: Ganos rasters fail to be updated in some scenarios.

The following issue is fixed: An unexpected exit may occur after the binary files of Ganos are upgraded to later versions.

The following issue is fixed: The data volume of top-level tiles is excessively large after the point data of vector pyramids is built by using the default parameters.

Category

Feature

Description

References

New feature

GROUP_ID function

The GROUP_ID() function is supported.

GROUP_ID

Partitioned table

The CREATE INDEX CONCURRENTLY statement is supported. This way, you can concurrently create indexes on partitioned tables.

None

Support for making indexes of standard tables invisible

The ALTER INDEX [NAME] INVISIBLE statement is supported. You can execute this statement to make an index of a standard table invisible.

None

ali_decoding plug-in

The ali_decoding plug-in is supported. This plug-in is used to synchronize incremental DML statements between databases.

None

pg_cron plug-in

The pg_cron plug-in is supported. This plug-in is used to query the records of scheduled tasks.

PG_CRON

to_char()

Strings can be specified in the TO_CHAR() function.

None

Data type

The following operators are added to compare the prid_ data type of the ROWID column with a string data type such as TEXT. These operators are also used to compare a string data type such as TEXT with the prid_ data type of the ROWID column.

• <

• <=

• >

• >=

• =

• <>

None

View

The views that display process status statistics are added.

None

The views that display time consumption statistics for SQL statements are added.

None

Audit log

SQL errors are recorded in audit logs.

None

Fixed issue

The following issue is fixed: In specific scenarios, page prefetching may cause deadlocks.

The following issue is fixed: A JOIN query fails to retrieve the accurate partition during partition pruning.

Category

Feature

Description

References

New feature

Support for the subset raster in a NetCDF raster file that has multiple subsets

The subset raster in a NetCDF raster file that has multiple subsets can be imported. You can specify the subset name to import the subset raster.

None

Custom metadata and time series information of rasters

The ST_MetaItems function is supported. This function is used to obtain the names of all custom metadata items.

ST_MetaItems

The ST_MetaData function is supported. This function is used to obtain custom metadata items of a raster and return custom metadata items in the JSON format.

ST_MetaData

The ST_SetMetaData function is supported. This function is used to specify a metadata item.

ST_SetMetaData

The ST_BeginDateTime function is supported. This function is used to obtain the start time of a raster.

ST_BeginDateTime

The ST_EndDateTime function is supported. This function is used to obtain the end time of a raster.

ST_EndDateTime

The ST_SetBeginDateTime function is supported. This function is used to configure the start time of a raster.

ST_SetBeginDateTime

The ST_SetEndDateTime function is supported. This function is used to configure the end time of a raster.

ST_SetEndDateTime

The ST_SetDateTime function is supported. This function is used to configure the start time and end time of a raster and the time when a band is obtained.

ST_SetDateTime

Support for converting a raster into a BYTEA-type image

The ST_AsImage function is supported. This function is used to convert a raster into a BYTEA-type image.

ST_AsImage

The ST_AsPng function is supported. This function is used to convert a raster into a BYTEA-type PNG image.

ST_AsPNG

The ST_AsJPEG function is supported. This function is used to convert a raster into a BYTEA-type JPEG image.

ST_AsJPEG

Support for the GeomGrid data type and operations

The GeomGrid data type is supported.

GeomGrid SQL reference

The ST_AsText function is supported. This function is used to convert a grid into a text representation.

ST_AsText

The ST_AsGeometry function is supported. This function is used to obtain the geometric representation of a grid.

ST_AsGeometry

The ST_AsBinary function is supported. This function is used to convert a grid into a binary representation.

ST_AsBinary

The ST_AsBox function is supported. This function is used to obtain the box representation of a grid.

ST_AsBox

The ST_AsGrid function is supported. This function is used to query the grids that intersect with a geometric object.

ST_AsGrid

The ST_GridFromText function is supported. This function is used to convert a grid from a text representation into a GeomGrid representation.

ST_GridFromText

The ST_GridFromBinary function is supported. This function is used to convert a grid from a binary representation into a GeomGrid representation.

ST_GridFromBinary

The ST_Intersects function is supported. This function is used to identify the spatial relationship between two raster objects or between a raster object and a geometric object. This function allows you to check whether the first specified object intersects with the second specified object.

ST_Intersects

The ST_Contains function is supported. This function is used to identify the spatial relationship between two raster objects or between a raster object and a geometric object. This function allows you to check whether the first specified object contains the second specified object.

ST_Contains

The ST_Within function is supported. This function is used to identify the spatial relationship between two grid objects or between a grid object and a geometric object. This function allows you to check whether the first specified object is within the second specified object.

ST_Within

Rapid display and storage of vector data

The ST_BuildPyramid function is supported. This function is used to create a vector pyramid.

ST_BuildPyramid

The ST_DeletePyramid function is supported. This function is used to delete a vector pyramid.

ST_DeletePyramid

The ST_Tile function is supported. This function is used to obtain vector data in the MVT format.

ST_Tile

Fixed issue

The following issue is fixed: In some cases, OOM errors occur when you create pyramids.

The following issue is fixed: Trajectory objects on January 1, 2000 cannot be created.

The following issue is fixed: In some scenarios, an invalid trajectory is returned when the ST_Intersection function is used for trajectory objects.

The following issue is fixed: The system stops responding during a Ganos upgrade.

This minor version is compatible with PostGIS 2.5.4.

Category

Feature

Description

References

New feature

View

The views that display SQL execution statistics are added.

None

The views that display queries per second (QPS) statistics are added.

None

The views that display CGroup status statistics are added.

None

Privileged account

The SELECT permissions on dba_* views are granted to the accounts that have the polar_superuser permissions.

None

Fixed issue

The following issue is fixed: A display error is returned for the polar_stat_io_info view.

The following issue is fixed: The AWR system wait information is missing.

The following issue is fixed: An error occurs during partition pruning for a partitioned table.

The following issue is fixed: An error occurs when the Segmented Least Recently Used (SLRU) algorithm is used to calculate the memory size.

The following issue is fixed: Read-only nodes are recreated due to a playback latency.

Category

Feature

Description

References

New feature

Support for Cloud Optimized GeoTIFF (COG) files

The COG files are supported. The pyramid information that is stored in COG files can be read.

None

ST_AddZ function

The ST_AddZ function is supported. This function is used to specify the Z coordinate of a geometry object based on the pixel value of the raster that is converted from the geometry object.

ST_AddZ

Enhanced capabilities for obtaining the spatial extent information about raster objects

The ST_Extent function is supported. This function is used to retrieve the spatial extent of a raster object and return the box representation of the raster object.

ST_Extent

The ST_Envelope function is supported. This function is used to retrieve the spatial extent of a raster object and return the spatial extent in the format of a geometry object.

ST_Envelope

The ST_ConvexHull function is supported. This function is used to retrieve the spatial extent of a raster object and return the spatial extent in the format of a geometry object.

ST_ConvexHull

The ST_Height function is supported. This function is used to retrieve the pixel height of a raster object.

ST_Height

The ST_Width function is supported. This function is used to retrieve the pixel width of a raster object.

ST_Width

Fixed issue

The following issue is fixed: Performance bottlenecks occur when raster objects that are stored in external storage locations use a chunking dimension of 1 × n. You can configure storage parameters to customize the size of the chunking dimension.

The following issue is fixed: The returned values are different from the coordinate values when you use the ST_Values function to obtain values in some directions.

The following issue is fixed: The ST_BestPyramidLevel function returns a negative value.

The following issue is fixed: The ST_BuildPyramid function repeatedly creates pyramids.

The following issue is fixed: The block table of a raster table is not deleted when you truncate the raster table.

The following issue is fixed: The ST_ExportTo function is invalid for CreateOption in some cases.

The following issue is fixed: If a table name contains uppercase and lowercase letters, the ST_ClearChunks function fails.

The following issue is fixed: An external pyramid cannot create an overview.

The following issue is fixed: Raster objects that have external pyramids cannot create internal pyramids.

The following issue is fixed: Invalid results are returned when you calculate the raster data that contains NaN values.

Category

Feature

Description

References

New feature

Pivot syntax

An alias can be specified for a table or a subquery in the Pivot syntax.

None

ROWID pseudocolumn

The ROWID pseudocolumn and the ROWIDTOCHAR and CHARTOROWID functions are supported.

None

Built-in functions

The LNNVL, DUMP, SYS_CONTEXT, USERENV, TZ_OFFSET, and VSIZE functions are supported.

None

DBMS_JOB and DBMS_SCHEDULER

DBMS_JOB and DBMS_SCHEDULER are supported. They are used to maintain and manage jobs.

None

Temporary tables

Temporary tables can be written to local storage. This improves the read and write performance of temporary tables.

None

Event trigger

Logical replication can be performed on events captured by the event trigger. Accounts that have the polar_superuser permissions can perform logical replication.

None

Custom resource group

Requests can be initiated by custom resource groups.

None

Optimized feature

Process of recovery from a failure

The process to recover from a failure is optimized. This reduces the amount of time that is required to recover from a severe failure.

None

Fixed issue

The following issue is fixed: Accounts that have the polar_superuser permissions cannot use the Index Advisor.

Category

Feature

Description

References

New feature

Enhanced interfaces that are used to access raster metadata

The ST_XMin function is supported. This function is used to obtain the minimum value in a set of rasters on the X-axis.

ST_XMin

The ST_YMin function is supported. This function is used to obtain the minimum value in a set of rasters on the Y-axis.

ST_YMin

The ST_XMax function is supported. This function is used to obtain the maximum value in a set of rasters on the X-axis.

ST_XMax

The ST_YMax function is supported. This function is used to obtain the maximum value in a set of rasters on the Y-axis.

ST_YMax

The ST_ChunkHeight function is supported. This function is used to obtain the height of a raster tile.

ST_ChunkHeight

The ST_ChunkWidth function is supported. This function is used to obtain the width of a raster tile.

ST_ChunkWidth

The ST_ChunkBands function is supported. This function is used to obtain the number of bands of a raster tile.

ST_ChunkBands

ST_SrFromEsriWkt function

The ST_SrFromEsriWkt function is supported. This function is used to convert the format of a spatial reference string from Esri into Open Geospatial Consortium (OGC).

ST_SrFromEsriWkt

Raster data type

Raster data files can be compressed by using the Zstandard (zstd) compression algorithm or the Snappy compression library.

None

Point cloud data type

Point cloud files can be copied in binary mode.

None

Environment variables

The PROJ_LIB and GDAL_DATA environment variables can be configured, and the relevant data can be deployed.

None

Fixed issue

The following issue is fixed: Databases do not respond due to invalid OSS paths.

The following issue is fixed: After raster data is imported to databases, the SRIDs of some raster data are inconsistent with the original SRIDs.

Category

Feature

Description

References

New feature

NVL2 function

The NVL2 function is supported. This function is used to return the value of the second or third parameter based on whether the value of the first parameter is NULL or an empty string.

None

polar_proxy_utils plug-in

The polar_proxy_utils plug-in is supported. This plug-in is used to manage proxy-related features. This plug-in allows you to configure read-only Universal Disk Format (UDF) files and read-only tables. This plug-in also allows you to use a cluster endpoint to route requests for accessing read-only UDF files and read-only tables to the read-only nodes in the cluster.

None

polar_resource_group plug-in

The polar_resource_group plug-in is supported. This plug-in is used to customize resource groups. You can use the custom resource groups to isolate resources such as CPUs and memory on a per-user, per-database, or per-session basis.

None

Optimized feature

Reliability and availability

The compute nodes of databases are decoupled from file systems. This allows you to perform O&M operations on the file systems. This improves the reliability and availability of databases.

None

Transaction processing

The snapshot of the active transaction list is replaced with a commit sequence number (CSN). Each CSN is a monotonically increasing identifier. This improves the transaction processing performance of databases.

None

Execution plan

Execution plans are optimized to prevent obsolete statistics from being used.

None

Fixed issue

The following issue is fixed: A database process failure occurs when the timescaledb plug-in fails to request memory resources.

The following issue is fixed: The I/O monitoring feature does not provide data statistics after a process exits.

The following issue is fixed: A null pointer exception may occur after lock_debug is enabled.

The following issue is fixed: The pg_cron plug-in becomes unavailable.

Known issues of distributed shared memory (DSM) deadlocks in the community edition are fixed.

The following issue is fixed: The number of connections exceeds the upper limit.

Category

Feature

Description

References

New feature

TO_SINGLE_BYTE function

The TO_SINGLE_BYTE function is supported. This function is used to convert multi-byte characters in a string into single-byte characters.

TO_SINGLE_BYTE and TO_MULTI_BYTE functions

TO_MULTI_BYTE function

The TO_MULTI_BYTE function is supported. This function is used to convert single-byte characters in a string into multi-byte characters.

TO_SINGLE_BYTE and TO_MULTI_BYTE functions

REGEXP_LIKE function

The REGEXP_LIKE function is supported. You can use this function in a way similar to how the LIKE conditional expression is used. The REGEXP_LIKE function complies with the POSIX regular expression standard.

None

RATIO_TO_REPORT function

The RATIO_TO_REPORT function is supported. This function is used to calculate the ratio of a value to the sum of a set of values.

None

DBMS_UTILITY.FORMAT_ERROR_STACK function

The DBMS_UTILITY.FORMAT_ERROR_STACK function (macro) is supported. This function is used to return stack information and error messages layer by layer.

None

UTL_I18N.ESCAPE_REFERENCE and UTL_I18N.UNESCAPE_REFERENCE functions

The UTL_I18N.ESCAPE_REFERENCE and UTL_I18N.UNESCAPE_REFERENCE functions are supported. These functions provide escape and unescape mechanisms for HTML or XML characters.

None

INSERT ALL statement

The INSERT ALL statement is supported. You can execute the INSERT ALL statement to insert data into multiple tables at a time.

None

polar_concurrency_control plug-in

The polar_concurrency_control plug-in is supported. This plug-in is used to configure a concurrency limit on transaction executions, SQL queries, stored procedures, and DML operations. You can customize large queries and configure a concurrency limit on large queries to improve the execution efficiency in high concurrency scenarios.

None

pldebugger plug-in

The pldebugger plug-in is supported. This plug-in is used to debug local stored procedures. You can use the client pgAdmin4 V4.19 or later.

pldebugger

oss_fdw plug-in

The oss_fdw plug-in is supported. This plug-in is used to support external tables of Alibaba Cloud OSS. You can use OSS external tables to write data of databases to OSS or load data from OSS to databases. You can use multiple external tables in parallel or compress data during imports and exports. This improves the performance of data imports and exports. You can also use this feature to separate hot data from cold data that are stored in a wide range of storage media.

Read and write foreign data files by using oss_fdw

Optimized feature

ROUND function

The ROUND function is optimized to support the Interval data type. The returned values are measured in days.

ROUND

polar_stat_activity view

The polar_stat_activity view is optimized. The wait_info and wait_time columns are added. The wait_info column displays the object for which the current process is waiting. The wait_time column displays the amount of time for which the process needs to wait. If the object is a process, the process identifier (PID) is displayed. If the object is a file, the file descriptor (FD) is displayed.

None

Index

The pre-extension feature is supported. This feature automatically adds additional index pages when index pages are insufficient for new indexes. This improves the execution performance when data is inserted into a table that has indexes.

None

Category

Feature

Description

References

New feature

MD5 functions

The ST_MD5Sum function is supported. This function is used to obtain the MD5 hash value of a raster object.

ST_MD5Sum

The ST_SetMD5Sum function is supported. This function is used to configure the MD5 hash value of a raster object.

ST_SetMD5Sum

Authentication method of spatial raster objects that are stored in OSS

The ST_AKId function is supported. This function is used to obtain the AccessKey ID that is used to access a raster object stored in OSS.

ST_AKId

The ST_SetAccessKey function is supported. This function is used to configure the AccessKey ID and the AccessKey secret that are used to access a raster object stored in OSS.

ST_SetAccessKey

The ST_SetAKId function is supported. This function is used to configure the AccessKey ID that is used to access a raster object stored in OSS.

ST_SetAKId

The ST_SetAKSecret function is supported. This function is used to configure the AccessKey secret that is used to access a raster object stored in OSS.

ST_SetAKSecret

Functions that are used to manage spatial raster metadata

The ST_ScaleX function is supported. This function is used to obtain the pixel width of a raster object on the X-axis of the spatial reference system.

ST_ScaleX

The ST_ScaleY function is supported. This function is used to obtain the pixel width of a raster object on the Y-axis of the spatial reference system.

ST_ScaleY

The ST_SetScale function is supported. This function is used to configure the pixel width of a raster object in the spatial reference system.

ST_ScaleY

The ST_SkewX function is supported. This function is used to obtain the skew of a raster object on the X-axis of the spatial reference system.

ST_SkewX

The ST_SkewY function is supported. This function is used to obtain the skew of a raster object on the Y-axis of the spatial reference system.

ST_SkewY

The ST_SetSkew function is supported. This function is used to specify the skew of a raster object in the spatial reference system.

ST_SetSkew

The ST_UpperLeftX function is supported. This function is used to obtain the upper-left X-coordinate of a raster object in the spatial reference system.

ST_UpperLeftX

The ST_UpperLeftY function is supported. This function is used to obtain the upper-left Y-coordinate of a raster object in the spatial reference system.

ST_UpperLeftY

The ST_SetUpperLeft function is supported. This function is used to configure the upper-left coordinates of a raster object in the spatial reference system.

ST_SetUpperLeft

The ST_PixelWidth function is supported. This function is used to obtain the pixel width of a raster object in the spatial reference system.

ST_PixelWidth

The ST_PixelHeight function is supported. This function is used to obtain the pixel height of a raster object in the spatial reference system.

ST_PixelHeight

Fixed issue

The following issue is fixed: Aggregate functions result in extension upgrade failures.