Updated on 2023-10-12 GMT+08:00

Top FAQs

Recently, we have collected FAQs about GaussDB(DWS) through Intelligent chatbot. You can find answers to your questions on this page.

Syntax Usage

Table 1 Syntax Usage

Ranking

FAQ

Page URL

1

  • How do I query the number of bits in a query string?
  • How do I truncate a substring?
  • How do I replace some strings in the returned result?
  • How do I return the first several characters of a string?
  • How do I filter out the header and tail of a string?
  • How do I get the number of bytes of a specified string?

Character Processing Functions and Operators

2

  • How do I create a partition table?
  • What are the supported table partition types?

CREATE TABLE PARTITION

3

  • How do I view all schemas?
  • How do I view all tables in a schema?

Schema

4

  • How do I add a table column?
  • How do I change a data type?
  • How do I adding a NOT NULL constraint to a column?
  • How do I set the primary key?
  • How do I alter table attributes?

ALTER TABLE

5

  • How do I use date functions?
  • How do I use pg_sleep()?
  • How do I perform month subtraction?
  • How do I use functions to change date types?

Time and Date Processing Functions and Operators

6

  • How do I change distribution columns?
  • How do I change the distribution column to another column?
  • Why does the data in the distribution column cannot be updated, and the message "Distributed key column can't be updated in current version" is displayed?

How Do I Change Distribution Columns

7

  • How do I manage partitions?
  • How do I add or delete a partition?
  • How do I rename a partition?
  • How do I query data in a partition?

Creating and Managing Partitioned Tables

8

  • How do I query the number of rows in a partition?
  • How do I merge two partitions?

ALTER TABLE PARTITION

9

How do I call the stored procedure?

CALL

10

  • How do I create a table?
  • create table like

CREATE TABLE

11

  • What is the command for authorization?
  • How do I use the grant syntax?
  • How do I grant the rights of a user to other users?
  • How do I grant table permissions to a user?
  • How do I granting database permissions to a user?
  • What are the foreign table permissions?

GRANT

12

  • How do I use the REPLACE function?
  • How do I use to_timestamp?
  • How do I covert a timestamp to a specified format?
  • How do I use current_timestamp?
  • How do I use to_number?

Type Conversion Functions

Database Management

Table 2 Database management

Ranking

FAQ

Page URL

1

  • How do I view table definitions?
  • How do I view the DDL?
  • How do I view the structure of views?
  • How do I querying the size of a database or a table?

Querying the Table and Database Size

2

  • How do I clearing tablespaces?
  • How do I use the VACUUM FULL syntax?
  • How do I improve the query performance after a large number of adding, deleting, and modifying operations?

VACUUM

3

  • How do I check whether a user has permissions on the current table?
  • How do I check whether a user has a certain permission on a table?

How Do I View the Table Permissions of a User?

4

  • How do I query and terminate blocked statements?
  • How do I query active statements?
  • How do I terminate a session?
  • What should I do when lock waiting times out?

Analyzing SQL Statements That Are Being Executed

5

  • Is there a detailed description for SQL execution plans?
  • How do I view the execution plan?
  • What are the differences between Nested Loop, Hash Join, and Merge Join?

Deep Dive on the SQL Execution Plan

6

  • How do I Cancel THE read-only status?
  • What should I do when the database enters the read-only state?

A GaussDB(DWS) Cluster Becomes Read-Only and Is Locked and Data Cannot Be Written

7

  • How do I collect statistics?

ANALYZE | ANALYSE

8

  • How do I configure the optimizer?
  • How do I enable or disable nestloop?
  • How do I enable or disable mergejoin?
  • What are the parameters that affect the execution plan?

Optimizer Method Configuration

9

  • How do I changing the database time zone?
  • How do I change the time zone?

How to Change a Database's Default Time Zone When the Database Time Is Different from the System Time?

10

  • How do I query function definitions?
  • How do I use the access privilege inquiry functions?
  • How do I query view definitions?

System Information Functions

11

  • What are the technical specifications?
  • What are the supported partition table sizes?
  • What is the maximum data volume in a single table?
  • What is the maximum number of columns supported by a table?

Technical Specifications

12

  • What are the developer operations?
  • How do I specify whether to enable the optimizer's use of a distributed framework?

Developer Options

Cluster Management

Table 3 Cluster management

Ranking

FAQ

Page URL

1

  • What should I do when disk usage is too high?
  • What should I do if the disk is full?
  • What should I do if the cluster becomes read-only?
  • What should I do if a disk alarm is generated?
  • How do I set the disk threshold?
  • How do I enable disk alarm subscription?

A GaussDB(DWS) Cluster Becomes Read-Only and Is Locked and Data Cannot Be Written

2

  • How do I view basic cluster information?
  • How do I viewing the EIP of a cluster?
  • How do I viewing the database connection address?
  • What are the cluster flavors?
  • What is the basic disk information?

Viewing Cluster Details

3

How do I purchase a cluster?

Creating a Cluster

4

  • What should I do if the cluster is unbalanced?
  • How do I perform primary/standby cluster switchover?

Performing a Primary/Standby Switchback