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Kernel Requirement Logs

Updated at: Sep 17, 2021 GMT+08:00
Table 1 8.1.1 kernel requirements

New Feature

Description

Reference

2048 nodes in a GaussDB(DWS) cluster

Supported up to 2048 nodes in a cluster.

"System Overview > Technical Specifications" in the Developer Guide

Query bands in a resource pool queue

  1. Added the load identification based on query bands.
  2. Added the system catalog PG_WORKLOAD_ACTION and system view PG_QUERYBAND_ACTION.
  3. Added resource management functions gs_wlm_set_queryband_action, gs_wlm_set_queryband_order, and gs_wlm_get_queryband_action.
  1. "Resource Load Management > Resource Management Preparation" in the Developer Guide
  2. "System Catalogs and System Views" in the Developer Guide
  3. "Functions and Operators > System Administration Functions > Resource Management Functions" in the SQL Syntax

Schema space control

  1. Added "Viewing Schema Space Information" to "Schema Space Control".
  2. Added the system view PG_TOTAL_SCHEMA_INFO.
  1. "Resource Load Management > Resource Management Preparation > Schema Space Control" in the Developer Guide
  2. "System Catalogs and System Views > System Views > PG_TOTAL_SCHEMA_INFO" in the Developer Guide

Resource monitoring performance tuning

  1. Added functions pgxc_wlm_get_schema_space(cstring) and pgxc_wlm_analyze_schema_space(cstring).
  2. Added system views PGXC_TOTAL_SCHEMA_INFO, PGXC_TOTAL_SCHEMA_INFO_ANALYZE, and GS_WLM_SQL_ALLOW.
  1. "Functions and Operators > System Administration Functions > Resource Management Functions" in the SQL Syntax
  2. "System Catalogs and System Views > System Views" in the Developer Guide

Lightweight UPDATE

  1. Added descriptions about column-store tables and the lightweight UPDATE operation on column-store tables to "Precautions".
  2. Added the GUC parameter enable_light_colupdate.
  1. "DML Syntax > UPDATE" in the SQL Syntax
  2. "GUC Parameters > Developer Operations" in the Developer Guide

Primary key CU of column-store tables

Column-store tables support primary key constraints.

  1. "Development and Design Proposal > Database Object Design > Constraint Design" in the Developer Guide
  2. "DDL Syntax > ALTER TABLE/CREATE INDEX" in the SQL Syntax

Space management

Added the GUC parameter bi_page_reuse_factor.

"GUC Parameters > Resource Consumption > Disk Space" in the Developer Guide

GDS productization

Added system views PGXC_BULKLOAD_PROGRESS, PGXC_BULKLOAD_STATISTICS, and PG_BULKLOAD_STATISTICS.

"System Catalogs and System Views > System Views" in the Developer Guide

Hot and cold data storage

  1. Added the description of REFRESH STORAGE to "ALTER TABLE".
  2. Added the functions and descriptions of COLVERSION and STORAGE_POLICY to "CREATE TABLE".
  3. Added the function and description of the OBS tablespace to "CREATE TABLESPACE".

"DDL Syntax" in the SQL Syntax

C function in SM4 CBC mode

Added security functions gs_encrypt(encryptstr, keystr, cryptotype, cryptomode, hashmethod), gs_decrypt(decryptstr, keystr, cryptotype, cryptomode, hashmethod), and gs_hash(hashstr, hashmethod).

Modified the description of gs_encrypt_aes128(encryptstr, keystr) and gs_decrypt_aes128(decryptstr, keystr).

"Functions and Operators > Security Functions" in the SQL Syntax

Support for the built-in MEDIAN function

Added the function median(expression).

"Functions and Operators > Aggregate Functions" in the SQL Syntax

WDR report

  1. Added "WDR Performance Analysis".
  2. Added WDR-related functions.
  3. Added functions starting with pg_stat_get_db_total_.
  4. Added the system catalogs SNAPSHOT and TABLES_SNAP_TIMESTAMP and system catalogs for performance view snapshots.
  5. Added the following system views:

    PGXC_REPLICATION_SLOTS

    PGXC_SETTINGS

    PGXC_STAT_BGWRITER

    PGXC_INSTANCE_TIME

    PGXC_OS_RUN_INFO

    GLOBAL_WORKLOAD_TRANSACTION

    PV_REDO_STAT and PGXC_REDO_STAT

    GLOBAL_REDO_STAT

    GS_REL_IOSTAT

    PGXC_REL_IOSTAT

    GLOBAL_REL_IOSTAT

    GS_NODE_STAT_RESET_TIME

    GS_WAIT_EVENTS

    PGXC_WAIT_EVENTS

  1. WDR Performance Analysis in the Developer Guide
  2. "Functions and Operators > System Administration Functions > Other Functions" in the SQL Syntax
  3. "Functions and Operators > Statistics Information Functions" in the SQL Syntax
  4. "System Catalogs and System Views > System Catalogs" in the Developer Guide
  5. "System Catalogs and System Views > System Views" in the Developer Guide

Adjusting the cascade delete for tables with views

  1. Added the description of rebuilding a view.
  2. Added the following description to the REBUILD parameter of ALTER VIEW: Only fields of the character, number, and time types in the base table can be modified. When view_independent is set to on, views can be automatically rebuilt.
  1. "Database Quick Start > Creating and Managing Views" in the Getting Started
  2. "DDL Syntax > ALTER VIEW" in the SQL Syntax

Custom data redaction

  1. Optimized data redaction.
  2. Provided data redaction functions in different forms.
  3. Updated the columns in the system catalog PG_REDACTION_COLUMN and system view REDACTION_COLUMNS.
  4. Added the syntax ALTER REDACTION POLICY, CREATE REDACTION POLICY, and DROP REDACTION POLICY.
  1. "Database Security Management > Data Masking" in the Developer Guide
  2. "Functions and Operators > Data Masking Functions" in the SQL Syntax
  3. "System Catalogs and System Views > System Catalogs/System Views" in the Developer Guide
  4. "DDL Syntax > ALTER/CREATE/DROP REDACTION POLICY" in the SQL Syntax

After the password expires, a user can log in to the database only after changing the password.

1. "Keyword" in the SQL Syntax

Added EXPIRATION (non-reserved).

2. Added the security function gs_password_expiration, and the description that the system prompts users to change their passwords after the gs_password_deadline password expires. This is related to the GUC parameter password_effect_time.

3. Added PASSWORD EXPIRATOIN period to the syntax ALTER ROLE, ALTER USER, and CREATE USER.

4. Added the following description to CREATE ROLE: number of days before the login password of a role expires. Users need to change the password before it expires. If the login password expires, the user cannot log in to the system. In this case, the user needs to ask the administrator to set a new login password and use it to log in to the system.

5. Added the columns rolauthinfo, rolpwdexpire, and rolpwdtim to the system catalog PG_AUTHID.

  1. "Keyword" in the SQL Syntax
  2. "Functions and Operators > Security Functions" in the SQL Syntax
  3. "DDL Syntax > ALTER ROLE /ALTER USER/CREATE USER" in the SQL Syntax
  4. "DDL Syntax > CREATE ROLE" in the SQL Syntax
  5. "System Catalogs and System Views > System Catalogs > PG_AUTHID" in the Developer Guide

Increasing the hash table size

Added the GUC parameter expand_hashtable_ratio.

"GUC Parameters > Query Planning > Other Optimizer Options" in the SQL Syntax

SMP adaptation enabled

Added "Suggestions for SMP Parameter Settings".

"Query Performance Optimization > Query Improvement > Configuring the SMP > Suggestions for SMP Parameter Settings"

PRETTY as the default value of EXPLAIN

Changed the default display format of EXPLAIN to PRETTY.

Added the statistics of filtering and projection time to the new operator. The statistics and the operator execution time are displayed in the same row.

"Query Performance Optimization > Query Analysis > Introduction to the SQL Execution Plan" in the Developer Guide

Enhanced concurrent SMP

  1. Added the constraint of SMP: the short query scenario where the plan generation time accounts for a large proportion.
  2. Added the description of setting query_dop to 1 in the short query scenario.
  3. Added the GUC parameter query_dop_ratio.
  1. "Query Improvement > Configuring the SMP > Application Scenarios and Restrictions" in the Developer Guide
  2. "Query Improvement > Configuring the SMP > SMP Manual Optimization Suggestions" in the Developer Guide
  3. "GUC Parameters > Query Planning > Other Optimizer Options" in the SQL Syntax

row2vec optimization

Added the GUC parameter enable_row_fast_numeric.

"GUC Parameters > Developer Operations" in the Developer Guide

MySQL compatibility

  1. Added the negative processing of concat, log(x), left, and right, last_day and next_day return types of int + unknown operations, and compatibility differences of the operator ^.
  2. Added the keywords IFNULL and TIMESTAMPDIFF.
  3. Added the description of processing CASE, COALESCE, IF, and IFNULL in MySQL-compatible mode.
  4. Added the MySQL-compatible schema and example of the behavior_compat_options option.
  5. The SELELCT, SELECT INTO, and VALUES support [ OFFSET start [ ROW | ROWS ] ] | LIMIT start, { count | ALL } } ].
  6. Added MySQL compatibility to the DBCOMPATIBILITY of CREATE DATABASE.
  7. Added the following content: compatibility differences between concat(str1, str2), left(str text, n int), and right(str text, n int) for character processing functions and operators; compatibility differences between log(x) and ^ for numeric operation functions and operators; time and date processing functions and operators, timestampdiff(field, timestamp1, timestamp2) /to_days(timestamp) /data_format; conditional expression functions, including if(bool_expr, expr1, expr2), ifnull(expr1, expr2), and isnull(expr).
  1. "Syntax Compatibility Differences Among Oracle, Teradata, and MySQL" in the Developer Guide
  2. "Keyword" in the SQL Syntax
  3. "Type Conversion > UNION, CASE, and Related Constructs" in the SQL Syntax
  4. "GUC Parameters > Miscellaneous Parameters > behavior_compat_options" in the Developer Guide
  5. "DML Syntax > SEELCT/SELECT INTO/VALUES" in the SQL Syntax
  6. "DDL Syntax > CREATE DATABASE"

    in the SQL Syntax

  7. "Functions and Operators > Character Processing Functions and Operators/Mathematical Functions and Operators/Date and Time Processing Functions and Operators/Conditional Expression Functions" in the SQL Syntax

Support for UPSERT

Added the UPSERT syntax.

Added IGNORE, AS, ON DUPLICATE KEY, and ON CONFLICT to the INSERT syntax.

"DML Syntax > INSERT > UPSERT" in the SQL Syntax

Support for the INSERT, UPDATE, and DELETE functions of views

Added Updatable Views to "CREATE VIEW".

"DDL Syntax > CREATE VIEW" in the SQL Syntax

One-click onsite information collection

Added the STATS boolean parameter to the EXPLAIN syntax.

"DML Syntax > EXPLAIN" in the SQL Syntax

One-click relationship analysis of a lock wait

  1. Added the lock information function pgxc_get_lock_conflicts().
  2. Added the system views PGXC_DEADLOCK and PGXC_LOCK_CONFLICTS.
  1. "Functions and Operators > System Information Functions" in the SQL Syntax
  2. "System Catalogs and System Views > System Views" in the Developer Guide

Combination with an empty string of the CHAR type

Added the configuration item bpchar_text_without_rtrim to the parameter behavior_compat_option.

"GUC Parameters > Miscellaneous Parameters > behavior_compat_options" in the Developer Guide

Support for Python 3.x

Supported Python 3.

"Importing Data > Using GDS to Import Data from a Remote Server" in the Developer Guide

When to_date and to_timestamp process an empty string, 0001-01-01 is returned, and null is returned for TD.

  1. Added "Syntax Compatibility Differences Among Oracle, Teradata, and MySQL".
  2. Added the configuration item convert_empty_str_to_null_td to behavior_compat_options.
  1. "Syntax Compatibility Differences Among Oracle, Teradata, and MySQL" in the Developer Guide
  2. "GUC Parameters > Miscellaneous Parameters > behavior_compat_options" in the Developer Guide

Support for INSERT OVERWRITE

The INSERT OVERWRITE syntax is supported.

"DML Syntax > INSERT" in the SQL Syntax

Obtaining all views queried by the current user

Added the view GS_VIEW_DEPENDENCY_PATH.

"System Catalogs and System Views > System Views" in the Developer Guide

Support for percentile_disc and percentile_cont

Added the following aggregate functions:

percentile_disc(const) within group(order by expression)

percentile_cont(const) within group(order by expression)

"Functions and Operators > Aggregate Functions" in the SQL Syntax

ROUNDROBIN added for specifying the distribution mode during table creation

CREATE TABLE ... DISTRIBUTE BY ROUNDROBIN

"DML Syntax > ALTER TABLE/CREATE TABLE/CREATE TABLE AS/CREATE TABLE PARTITION/CREATE INDEX" in the SQL Syntax

"DML Syntax > MERGE INTO" in the SQL Syntax

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