v2.0
- About MogDB
- MogDB Introduction
- Comparison Between MogDB and openGauss
- MogDB Release Notes
- High Availability and Performance
- Open Source Components
- Usage Limitations
- Terms of Use
- Quick Start
- Installation Guide
- Container Installation
- Simplified Installation Process
- Standard Installation
- Manual Installation
- Administrator Guide
- Routine Maintenance
- Starting and Stopping MogDB
- Using the gsql Client for Connection
- Routine Maintenance
- Checking OS Parameters
- Checking MogDB Health Status
- Checking Database Performance
- Checking and Deleting Logs
- Checking Time Consistency
- Checking The Number of Application Connections
- Routinely Maintaining Tables
- Routinely Recreating an Index
- Data Security Maintenance Suggestions
- Log Reference
- Primary and Standby Management
- MOT Engine
- Introducing MOT
- Using MOT
- Concepts of MOT
- Appendix
- Column-store Tables Management
- Backup and Restoration
- Importing and Exporting Data
- Importing Data
- Exporting Data
- Upgrade Guide
- Common Fault Locating Cases
- Core Fault Locating
- When the TPC-C is running and a disk to be injected is full, the TPC-C stops responding
- Standby Node in the Need Repair (WAL) State
- Insufficient Memory
- Service Startup Failure
- "Error:No space left on device" Is Displayed
- After You Run the du Command to Query Data File Size In the XFS File System, the Query Result Is Greater than the Actual File Size
- File Is Damaged in the XFS File System
- Primary Node Is Hung in Demoting During a Switchover
- Disk Space Usage Reaches the Threshold and the Database Becomes Read-only
- Slow Response to a Query Statement
- Analyzing the Status of a Query Statement
- Forcibly Terminating a Session
- Analyzing Whether a Query Statement Is Blocked
- Low Query Efficiency
- "Lock wait timeout" Is Displayed When a User Executes an SQL Statement
- Table Size Does not Change After VACUUM FULL Is Executed on the Table
- An Error Is Reported When the Table Partition Is Modified
- Different Data Is Displayed for the Same Table Queried By Multiple Users
- When a User Specifies Only an Index Name to Modify the Index, A Message Indicating That the Index Does Not Exist Is Displayed
- Reindexing Fails
- An Error Occurs During Integer Conversion
- "too many clients already" Is Reported or Threads Failed To Be Created in High Concurrency Scenarios
- B-tree Index Faults
- Routine Maintenance
- Security Guide
- Database Security Management
- Performance Tuning
- System Optimization
- SQL Optimization
- WDR Snapshot Schema
- TPCC Performance Tuning Guide
- Developer Guide
- Application Development Guide
- Development Specifications
- Development Based on JDBC
- Overview
- JDBC Package, Driver Class, and Environment Class
- Development Process
- Loading the Driver
- Connecting to a Database
- Connecting to the Database (Using SSL)
- Running SQL Statements
- Processing Data in a Result Set
- Closing a Connection
- Example: Common Operations
- Example: Retrying SQL Queries for Applications
- Example: Importing and Exporting Data Through Local Files
- Example 2: Migrating Data from a MY Database to MogDB
- Example: Logic Replication Code
- JDBC API Reference
- java.sql.Connection
- java.sql.CallableStatement
- java.sql.DatabaseMetaData
- java.sql.Driver
- java.sql.PreparedStatement
- java.sql.ResultSet
- java.sql.ResultSetMetaData
- java.sql.Statement
- javax.sql.ConnectionPoolDataSource
- javax.sql.DataSource
- javax.sql.PooledConnection
- javax.naming.Context
- javax.naming.spi.InitialContextFactory
- CopyManager
- Development Based on ODBC
- Development Based on libpq
- Development Based on libpq
- libpq API Reference
- Database Connection Control Functions
- Database Statement Execution Functions
- Functions for Asynchronous Command Processing
- Functions for Canceling Queries in Progress
- Example
- Connection Characters
- Commissioning
- Appendices
- Stored Procedure
- User Defined Functions
- Autonomous Transaction
- Logical Replication
- Logical Decoding
- Foreign Data Wrapper
- Materialized View
- Materialized View Overview
- Full Materialized View
- Incremental Materialized View
- AI Features
- Overview
- Predictor: AI Query Time Forecasting
- X-Tuner: Parameter Optimization and Diagnosis
- SQLdiag: Slow SQL Discovery
- A-Detection: Status Monitoring
- Index-advisor: Index Recommendation
- DeepSQL
- Application Development Guide
- Reference Guide
- System Catalogs and System Views
- Overview of System Catalogs and System Views
- System Catalogs
- GS_AUDITING_POLICY
- GS_AUDITING_POLICY_ACCESS
- GS_AUDITING_POLICY_FILTERS
- GS_AUDITING_POLICY_PRIVILEGES
- GS_CLIENT_GLOBAL_KEYS
- GS_CLIENT_GLOBAL_KEYS_ARGS
- GS_COLUMN_KEYS
- GS_COLUMN_KEYS_ARGS
- GS_ENCRYPTED_COLUMNS
- GS_MASKING_POLICY
- GS_MASKING_POLICY_ACTIONS
- GS_MASKING_POLICY_FILTERS
- GS_MATVIEW
- GS_MATVIEW_DEPENDENCY
- GS_OPT_MODEL
- GS_POLICY_LABEL
- GS_WLM_INSTANCE_HISTORY
- GS_WLM_OPERATOR_INFO
- GS_WLM_PLAN_ENCODING_TABLE
- GS_WLM_PLAN_OPERATOR_INFO
- GS_WLM_USER_RESOURCE_HISTORY
- PG_AGGREGATE
- PG_AM
- PG_AMOP
- PG_AMPROC
- PG_APP_WORKLOADGROUP_MAPPING
- PG_ATTRDEF
- PG_ATTRIBUTE
- PG_AUTHID
- PG_AUTH_HISTORY
- PG_AUTH_MEMBERS
- PG_CAST
- PG_CLASS
- PG_COLLATION
- PG_CONSTRAINT
- PG_CONVERSION
- PG_DATABASE
- PG_DB_ROLE_SETTING
- PG_DEFAULT_ACL
- PG_DEPEND
- PG_DESCRIPTION
- PG_DIRECTORY
- PG_ENUM
- PG_EXTENSION
- PG_EXTENSION_DATA_SOURCE
- PG_FOREIGN_DATA_WRAPPER
- PG_FOREIGN_SERVER
- PG_FOREIGN_TABLE
- PG_INDEX
- PG_INHERITS
- PG_JOB
- PG_JOB_PROC
- PG_LANGUAGE
- PG_LARGEOBJECT
- PG_LARGEOBJECT_METADATA
- PG_NAMESPACE
- PG_OBJECT
- PG_OPCLASS
- PG_OPERATOR
- PG_OPFAMILY
- PG_PARTITION
- PG_PLTEMPLATE
- PG_PROC
- PG_RANGE
- PG_RESOURCE_POOL
- PG_REWRITE
- PG_RLSPOLICY
- PG_SECLABEL
- PG_SHDEPEND
- PG_SHDESCRIPTION
- PG_SHSECLABEL
- PG_STATISTIC
- PG_STATISTIC_EXT
- PG_SYNONYM
- PG_TABLESPACE
- PG_TRIGGER
- PG_TS_CONFIG
- PG_TS_CONFIG_MAP
- PG_TS_DICT
- PG_TS_PARSER
- PG_TS_TEMPLATE
- PG_TYPE
- PG_USER_MAPPING
- PG_USER_STATUS
- PG_WORKLOAD_GROUP
- PLAN_TABLE_DATA
- STATEMENT_HISTORY
- System Views
- GS_AUDITING
- GS_AUDITING_ACCESS
- GS_AUDITING_PRIVILEGE
- GS_CLUSTER_RESOURCE_INFO
- GS_INSTANCE_TIME
- GS_LABELS
- GS_MASKING
- GS_MATVIEWS
- GS_SESSION_MEMORY
- GS_SESSION_CPU_STATISTICS
- GS_SESSION_MEMORY_CONTEXT
- GS_SESSION_MEMORY_DETAIL
- GS_SESSION_MEMORY_STATISTICS
- GS_SQL_COUNT
- GS_WLM_CGROUP_INFO
- GS_WLM_PLAN_OPERATOR_HISTORY
- GS_WLM_REBUILD_USER_RESOURCE_POOL
- GS_WLM_RESOURCE_POOL
- GS_WLM_USER_INFO
- GS_STAT_SESSION_CU
- GS_TOTAL_MEMORY_DETAIL
- MPP_TABLES
- PG_AVAILABLE_EXTENSION_VERSIONS
- PG_AVAILABLE_EXTENSIONS
- PG_COMM_DELAY
- PG_COMM_RECV_STREAM
- PG_COMM_SEND_STREAM
- PG_COMM_STATUS
- PG_CONTROL_GROUP_CONFIG
- PG_CURSORS
- PG_EXT_STATS
- PG_GET_INVALID_BACKENDS
- PG_GET_SENDERS_CATCHUP_TIME
- PG_GROUP
- PG_GTT_RELSTATS
- PG_GTT_STATS
- PG_GTT_ATTACHED_PIDS
- PG_INDEXES
- PG_LOCKS
- PG_NODE_ENV
- PG_OS_THREADS
- PG_PREPARED_STATEMENTS
- PG_PREPARED_XACTS
- PG_REPLICATION_SLOTS
- PG_RLSPOLICIES
- PG_ROLES
- PG_RULES
- PG_SECLABELS
- PG_SETTINGS
- PG_SHADOW
- PG_STATS
- PG_STAT_ACTIVITY
- PG_STAT_ALL_INDEXES
- PG_STAT_ALL_TABLES
- PG_STAT_BAD_BLOCK
- PG_STAT_BGWRITER
- PG_STAT_DATABASE
- PG_STAT_DATABASE_CONFLICTS
- PG_STAT_USER_FUNCTIONS
- PG_STAT_USER_INDEXES
- PG_STAT_USER_TABLES
- PG_STAT_REPLICATION
- PG_STAT_SYS_INDEXES
- PG_STAT_SYS_TABLES
- PG_STAT_XACT_ALL_TABLES
- PG_STAT_XACT_SYS_TABLES
- PG_STAT_XACT_USER_FUNCTIONS
- PG_STAT_XACT_USER_TABLES
- PG_STATIO_ALL_INDEXES
- PG_STATIO_ALL_SEQUENCES
- PG_STATIO_ALL_TABLES
- PG_STATIO_SYS_INDEXES
- PG_STATIO_SYS_SEQUENCES
- PG_STATIO_SYS_TABLES
- PG_STATIO_USER_INDEXES
- PG_STATIO_USER_SEQUENCES
- PG_STATIO_USER_TABLES
- PG_TABLES
- PG_TDE_INFO
- PG_THREAD_WAIT_STATUS
- PG_TIMEZONE_ABBREVS
- PG_TIMEZONE_NAMES
- PG_TOTAL_MEMORY_DETAIL
- PG_TOTAL_USER_RESOURCE_INFO
- PG_TOTAL_USER_RESOURCE_INFO_OID
- PG_USER
- PG_USER_MAPPINGS
- PG_VARIABLE_INFO
- PG_VIEWS
- PLAN_TABLE
- GS_FILE_STAT
- GS_OS_RUN_INFO
- GS_REDO_STAT
- GS_SESSION_STAT
- GS_SESSION_TIME
- GS_THREAD_MEMORY_CONTEXT
- Functions and Operators
- Logical Operators
- Comparison Operators
- Character Processing Functions and Operators
- Binary String Functions and Operators
- Bit String Functions and Operators
- Mode Matching Operators
- Mathematical Functions and Operators
- Date and Time Processing Functions and Operators
- Type Conversion Functions
- Geometric Functions and Operators
- Network Address Functions and Operators
- Text Search Functions and Operators
- JSON Functions
- HLL Functions and Operators
- SEQUENCE Functions
- Array Functions and Operators
- Range Functions and Operators
- Aggregate Functions
- Window Functions
- Security Functions
- Encrypted Equality Functions
- Set Returning Functions
- Conditional Expression Functions
- System Information Functions
- System Administration Functions
- Statistics Information Functions
- Trigger Functions
- Global Temporary Table Functions
- AI Feature Functions
- Other System Functions
- Internal Functions
- Obsolete Functions
- Supported Data Types
- SQL Syntax
- ABORT
- ALTER AGGREGATE
- ALTER AUDIT POLICY
- ALTER DATABASE
- ALTER DATA SOURCE
- ALTER DEFAULT PRIVILEGES
- ALTER DIRECTORY
- ALTER EXTENSION
- ALTER FOREIGN TABLE
- ALTER FUNCTION
- ALTER GROUP
- ALTER INDEX
- ALTER LANGUAGE
- ALTER LARGE OBJECT
- ALTER MASKING POLICY
- ALTER MATERIALIZED VIEW
- ALTER OPERATOR
- ALTER RESOURCE LABEL
- ALTER ROLE
- ALTER ROW LEVEL SECURITY POLICY
- ALTER RULE
- ALTER SCHEMA
- ALTER SEQUENCE
- ALTER SERVER
- ALTER SESSION
- ALTER SYNONYM
- ALTER SYSTEM KILL SESSION
- ALTER SYSTEM SET
- ALTER TABLE
- ALTER TABLE PARTITION
- ALTER TABLESPACE
- ALTER TEXT SEARCH CONFIGURATION
- ALTER TEXT SEARCH DICTIONARY
- ALTER TRIGGER
- ALTER TYPE
- ALTER USER
- ALTER USER MAPPING
- ALTER VIEW
- ANALYZE | ANALYSE
- BEGIN
- CALL
- CHECKPOINT
- CLOSE
- CLUSTER
- COMMENT
- COMMIT | END
- COMMIT PREPARED
- COPY
- CREATE AGGREGATE
- CREATE AUDIT POLICY
- CREATE CAST
- CREATE CLIENT MASTER KEY
- CREATE COLUMN ENCRYPTION KEY
- CREATE DATABASE
- CREATE DATA SOURCE
- CREATE DIRECTORY
- CREATE EXTENSION
- CREATE FOREIGN TABLE
- CREATE FUNCTION
- CREATE GROUP
- CREATE INCREMENTAL MATERIALIZED VIEW
- CREATE INDEX
- CREATE LANGUAGE
- CREATE MASKING POLICY
- CREATE MATERIALIZED VIEW
- CREATE OPERATOR
- CREATE ROW LEVEL SECURITY POLICY
- CREATE PROCEDURE
- CREATE RESOURCE LABEL
- CREATE ROLE
- CREATE RULE
- CREATE SCHEMA
- CREATE SEQUENCE
- CREATE SERVER
- CREATE SYNONYM
- CREATE TABLE
- CREATE TABLE AS
- CREATE TABLE PARTITION
- CREATE TABLESPACE
- CREATE TEXT SEARCH CONFIGURATION
- CREATE TEXT SEARCH DICTIONARY
- CREATE TRIGGER
- CREATE TYPE
- CREATE USER
- CREATE USER MAPPING
- CREATE VIEW
- CURSOR
- DEALLOCATE
- DECLARE
- DELETE
- DO
- DROP AGGREGATE
- DROP AUDIT POLICY
- DROP CAST
- DROP CLIENT MASTER KEY
- DROP COLUMN ENCRYPTION KEY
- DROP DATABASE
- DROP DATA SOURCE
- DROP DIRECTORY
- DROP EXTENSION
- DROP FOREIGN TABLE
- DROP FUNCTION
- DROP GROUP
- DROP INDEX
- DROP LANGUAGE
- DROP MASKING POLICY
- DROP MATERIALIZED VIEW
- DROP OPERATOR
- DROP OWNED
- DROP RESOURCE LABEL
- DROP ROW LEVEL SECURITY POLICY
- DROP PROCEDURE
- DROP ROLE
- DROP RULE
- DROP SCHEMA
- DROP SEQUENCE
- DROP SERVER
- DROP SYNONYM
- DROP TABLE
- DROP TABLESPACE
- DROP TEXT SEARCH CONFIGURATION
- DROP TEXT SEARCH DICTIONARY
- DROP TRIGGER
- DROP TYPE
- DROP USER
- DROP USER MAPPING
- DROP VIEW
- EXECUTE
- EXPLAIN
- EXPLAIN PLAN
- FETCH
- GRANT
- INSERT
- LOCK
- MOVE
- MERGE INTO
- PREPARE
- PREPARE TRANSACTION
- REASSIGN OWNED
- REFRESH INCREMENTAL MATERIALIZED VIEW
- REFRESH MATERIALIZED VIEW
- REINDEX
- RELEASE SAVEPOINT
- RESET
- REVOKE
- ROLLBACK
- ROLLBACK PREPARED
- ROLLBACK TO SAVEPOINT
- SAVEPOINT
- SELECT
- SELECT INTO
- SET
- SET CONSTRAINTS
- SET ROLE
- SET SESSION AUTHORIZATION
- SET TRANSACTION
- SHOW
- SHUTDOWN
- START TRANSACTION
- TRUNCATE
- UPDATE
- VACUUM
- VALUES
- SQL Reference
- MogDB SQL
- Keywords
- Constant and Macro
- Expressions
- Type Conversion
- Full Text Search
- Introduction
- Tables and Indexes
- Controlling Text Search
- Additional Features
- Parser
- Dictionaries
- Configuration Examples
- Testing and Debugging Text Search
- Limitations
- System Operation
- Controlling Transactions
- DDL Syntax Overview
- DML Syntax Overview
- DCL Syntax Overview
- Appendix
- GUC Parameters
- GUC Parameter Usage
- File Location
- Connection and Authentication
- Resource Consumption
- Parallel Import
- Write Ahead Log
- HA Replication
- Memory Table
- Query Planning
- Error Reporting and Logging
- Alarm Detection
- Statistics During the Database Running
- Load Management
- Automatic Vacuuming
- Default Settings of Client Connection
- Lock Management
- Version and Platform Compatibility
- Faut Tolerance
- Connection Pool Parameters
- MogDB Transaction
- Developer Options
- Auditing
- Upgrade Parameters
- Miscellaneous Parameters
- Wait Events
- Query
- System Performance Snapshot
- Equality Query in a Fully-encrypted Database
- Global Temporary Table
- Scheduled Task
- Thread Pool
- Appendix
- Information Schema
- DBE_PERF
- DBE_PERF Overview
- OS
- Instance
- Memory
- File
- Object
- STAT_USER_TABLES
- SUMMARY_STAT_USER_TABLES
- GLOBAL_STAT_USER_TABLES
- STAT_USER_INDEXES
- SUMMARY_STAT_USER_INDEXES
- GLOBAL_STAT_USER_INDEXES
- STAT_SYS_TABLES
- SUMMARY_STAT_SYS_TABLES
- GLOBAL_STAT_SYS_TABLES
- STAT_SYS_INDEXES
- SUMMARY_STAT_SYS_INDEXES
- GLOBAL_STAT_SYS_INDEXES
- STAT_ALL_TABLES
- SUMMARY_STAT_ALL_TABLES
- GLOBAL_STAT_ALL_TABLES
- STAT_ALL_INDEXES
- SUMMARY_STAT_ALL_INDEXES
- GLOBAL_STAT_ALL_INDEXES
- STAT_DATABASE
- SUMMARY_STAT_DATABASE
- GLOBAL_STAT_DATABASE
- STAT_DATABASE_CONFLICTS
- SUMMARY_STAT_DATABASE_CONFLICTS
- GLOBAL_STAT_DATABASE_CONFLICTS
- STAT_XACT_ALL_TABLES
- SUMMARY_STAT_XACT_ALL_TABLES
- GLOBAL_STAT_XACT_ALL_TABLES
- STAT_XACT_SYS_TABLES
- SUMMARY_STAT_XACT_SYS_TABLES
- GLOBAL_STAT_XACT_SYS_TABLES
- STAT_XACT_USER_TABLES
- SUMMARY_STAT_XACT_USER_TABLES
- GLOBAL_STAT_XACT_USER_TABLES
- STAT_XACT_USER_FUNCTIONS
- SUMMARY_STAT_XACT_USER_FUNCTIONS
- GLOBAL_STAT_XACT_USER_FUNCTIONS
- STAT_BAD_BLOCK
- SUMMARY_STAT_BAD_BLOCK
- GLOBAL_STAT_BAD_BLOCK
- STAT_USER_FUNCTIONS
- SUMMARY_STAT_USER_FUNCTIONS
- GLOBAL_STAT_USER_FUNCTIONS
- Workload
- Session/Thread
- SESSION_STAT
- GLOBAL_SESSION_STAT
- SESSION_TIME
- GLOBAL_SESSION_TIME
- SESSION_MEMORY
- GLOBAL_SESSION_MEMORY
- SESSION_MEMORY_DETAIL
- GLOBAL_SESSION_MEMORY_DETAIL
- SESSION_STAT_ACTIVITY
- GLOBAL_SESSION_STAT_ACTIVITY
- THREAD_WAIT_STATUS
- GLOBAL_THREAD_WAIT_STATUS
- LOCAL_THREADPOOL_STATUS
- GLOBAL_THREADPOOL_STATUS
- SESSION_CPU_RUNTIME
- SESSION_MEMORY_RUNTIME
- STATEMENT_IOSTAT_COMPLEX_RUNTIME
- Transaction
- Query
- STATEMENT
- SUMMARY_STATEMENT
- STATEMENT_COUNT
- GLOBAL_STATEMENT_COUNT
- SUMMARY_STATEMENT_COUNT
- GLOBAL_STATEMENT_COMPLEX_HISTORY
- GLOBAL_STATEMENT_COMPLEX_HISTORY_TABLE
- GLOBAL_STATEMENT_COMPLEX_RUNTIME
- STATEMENT_RESPONSETIME_PERCENTILE
- STATEMENT_USER_COMPLEX_HISTORY
- STATEMENT_COMPLEX_RUNTIME
- STATEMENT_COMPLEX_HISTORY_TABLE
- STATEMENT_COMPLEX_HISTORY
- STATEMENT_WLMSTAT_COMPLEX_RUNTIME
- STATEMENT_HISTORY
- Cache/IO
- STATIO_USER_TABLES
- SUMMARY_STATIO_USER_TABLES
- GLOBAL_STATIO_USER_TABLES
- STATIO_USER_INDEXES
- SUMMARY_STATIO_USER_INDEXES
- GLOBAL_STATIO_USER_INDEXES
- STATIO_USER_SEQUENCES
- SUMMARY_STATIO_USER_SEQUENCES
- GLOBAL_STATIO_USER_SEQUENCES
- STATIO_SYS_TABLES
- SUMMARY_STATIO_SYS_TABLES
- GLOBAL_STATIO_SYS_TABLES
- STATIO_SYS_INDEXES
- SUMMARY_STATIO_SYS_INDEXES
- GLOBAL_STATIO_SYS_INDEXES
- STATIO_SYS_SEQUENCES
- SUMMARY_STATIO_SYS_SEQUENCES
- GLOBAL_STATIO_SYS_SEQUENCES
- STATIO_ALL_TABLES
- SUMMARY_STATIO_ALL_TABLES
- GLOBAL_STATIO_ALL_TABLES
- STATIO_ALL_INDEXES
- SUMMARY_STATIO_ALL_INDEXES
- GLOBAL_STATIO_ALL_INDEXES
- STATIO_ALL_SEQUENCES
- SUMMARY_STATIO_ALL_SEQUENCES
- GLOBAL_STATIO_ALL_SEQUENCES
- GLOBAL_STAT_DB_CU
- GLOBAL_STAT_SESSION_CU
- Utility
- REPLICATION_STAT
- GLOBAL_REPLICATION_STAT
- REPLICATION_SLOTS
- GLOBAL_REPLICATION_SLOTS
- BGWRITER_STAT
- GLOBAL_BGWRITER_STAT
- GLOBAL_CKPT_STATUS
- GLOBAL_DOUBLE_WRITE_STATUS
- GLOBAL_PAGEWRITER_STATUS
- GLOBAL_RECORD_RESET_TIME
- GLOBAL_REDO_STATUS
- GLOBAL_RECOVERY_STATUS
- CLASS_VITAL_INFO
- USER_LOGIN
- SUMMARY_USER_LOGIN
- GLOBAL_GET_BGWRITER_STATUS
- Lock
- Wait Events
- Configuration
- Operator
- Workload Manager
- Global Plancache
- Appendix
- Tool Reference
- Tool Overview
- Client Tool
- Server Tools
- Tools Used in the Internal System
- Error Code Reference
- Description of SQL Error Codes
- Third-Party Library Error Codes
- GAUSS-00001 - GAUSS-00100
- GAUSS-00101 - GAUSS-00200
- GAUSS 00201 - GAUSS 00300
- GAUSS 00301 - GAUSS 00400
- GAUSS 00401 - GAUSS 00500
- GAUSS 00501 - GAUSS 00600
- GAUSS 00601 - GAUSS 00700
- GAUSS 00701 - GAUSS 00800
- GAUSS 00801 - GAUSS 00900
- GAUSS 00901 - GAUSS 01000
- GAUSS 01001 - GAUSS 01100
- GAUSS 01101 - GAUSS 01200
- GAUSS 01201 - GAUSS 01300
- GAUSS 01301 - GAUSS 01400
- GAUSS 01401 - GAUSS 01500
- GAUSS 01501 - GAUSS 01600
- GAUSS 01601 - GAUSS 01700
- GAUSS 01701 - GAUSS 01800
- GAUSS 01801 - GAUSS 01900
- GAUSS 01901 - GAUSS 02000
- GAUSS 02001 - GAUSS 02100
- GAUSS 02101 - GAUSS 02200
- GAUSS 02201 - GAUSS 02300
- GAUSS 02301 - GAUSS 02400
- GAUSS 02401 - GAUSS 02500
- GAUSS 02501 - GAUSS 02600
- GAUSS 02601 - GAUSS 02700
- GAUSS 02701 - GAUSS 02800
- GAUSS 02801 - GAUSS 02900
- GAUSS 02901 - GAUSS 03000
- GAUSS 03001 - GAUSS 03100
- GAUSS 03101 - GAUSS 03200
- GAUSS 03201 - GAUSS 03300
- GAUSS 03301 - GAUSS 03400
- GAUSS 03401 - GAUSS 03500
- GAUSS 03501 - GAUSS 03600
- GAUSS 03601 - GAUSS 03700
- GAUSS 03701 - GAUSS 03800
- GAUSS 03801 - GAUSS 03900
- GAUSS 03901 - GAUSS 04000
- GAUSS 04001 - GAUSS 04100
- GAUSS 04101 - GAUSS 04200
- GAUSS 04201 - GAUSS 04300
- GAUSS 04301 - GAUSS 04400
- GAUSS 04401 - GAUSS 04500
- GAUSS 04501 - GAUSS 04600
- GAUSS 04601 - GAUSS 04700
- GAUSS 04701 - GAUSS 04800
- GAUSS 04801 - GAUSS 04900
- GAUSS 04901 - GAUSS 05000
- GAUSS 05001 - GAUSS 05100
- GAUSS 05101 - GAUSS 05200
- GAUSS 05201 - GAUSS 05300
- GAUSS 05301 - GAUSS 05400
- GAUSS 05401 - GAUSS 05500
- GAUSS 05501 - GAUSS 05600
- GAUSS 05601 - GAUSS 05700
- GAUSS 05701 - GAUSS 05800
- GAUSS 05801 - GAUSS 05900
- GAUSS 05901 - GAUSS 06000
- GAUSS 06001 - GAUSS 06100
- GAUSS 06101 - GAUSS 06200
- GAUSS 06201 - GAUSS 06300
- GAUSS 06301 - GAUSS 06400
- GAUSS 06401 - GAUSS 06500
- GAUSS 06501 - GAUSS 06600
- GAUSS 06601 - GAUSS 06700
- GAUSS 06701 - GAUSS 06800
- GAUSS 06801 - GAUSS 06900
- GAUSS 06901 - GAUSS 07000
- GAUSS 07001 - GAUSS 07100
- GAUSS 07101 - GAUSS 07200
- GAUSS 07201 - GAUSS 07300
- GAUSS 07301 - GAUSS 07400
- GAUSS 07401 - GAUSS 07480
- GAUSS 50000 - GAUSS 50999
- GAUSS 51000 - GAUSS 51999
- GAUSS 52000 - GAUSS 52999
- GAUSS 53000 - GAUSS 53699
- System Catalogs and System Views
- FAQs
- Glossary
Connecting to a Database
After a database is connected, you can use JDBC to run SQL statements to operate data.
Function Prototype
JDBC provides the following three database connection methods:
- DriverManager.getConnection(String url);
- DriverManager.getConnection(String url, Properties info);
- DriverManager.getConnection(String url, String user, String password);
Parameter
Table 1 Database connection parameters
Parameter | Description |
---|---|
url | postgresql.jar database connection descriptor. The format is as follows: - jdbc:postgresql:database - jdbc:postgresql://host/database - jdbc:postgresql://host:port/database - jdbc:postgresql://host:port/database?param1=value1¶m2=value2 - jdbc:postgresql://host1:port1,host2:port2/database?param1=value1¶m2=value2 NOTE: - database indicates the name of the database to connect. - host indicates the name or IP address of the database server. If a machine connected to MogDB is not in the same network segment as MogDB, the IP address specified by host should be the value of coo.cooListenIp2 (application access IP address) set in Manager. For security purposes, the primary database node forbids access from other nodes in MogDB without authentication. To access the primary database node from inside MogDB, deploy the JDBC program on the host where the primary database node is located and set host to 127.0.0.1. Otherwise, the error message "FATAL: Forbid remote connection with trust method!" may be displayed. It is recommended that the service system be deployed outside MogDB. If it is deployed inside, database performance may be affected. By default, the local host is used to connect to the server. - port indicates the port number of the database server. By default, the database on port 5431 of the local host is connected. - param indicates a database connection attribute. The parameter can be configured in the URL. The URL starts with a question mark (?), uses an equal sign (=) to assign a value to the parameter, and uses an ampersand (&) to separate parameters. You can also use the attributes of the info object for configuration. For details, see the example below. - value indicates the database connection attribute values. |
info | Database connection attributes. Common attributes are described as follows: - PGDBNAME: string type. This parameter specifies the database name. (This parameter does not need to be set in the URL. The system automatically parses the URL to obtain its value.) - PGHOST: string type. This parameter specifies the host IP address. For details, see the example below. - PGPORT: integer type. This parameter specifies the host port number. For details, see the example below. - user: string type. This parameter specifies the database user who creates the connection. - password: string type. This parameter specifies the password of the database user. - loggerLevel: string type. The following log levels are supported:OFF, DEBUG, and TRACE. The value OFF indicates that the log function is disabled. DEBUG and TRACE logs record information of different levels. - loggerFile: string type. This parameter specifies the name of a log file. You can specify a directory for storing logs. If no directory is specified, logs are stored in the directory where the client program is running. - allowEncodingChanges: Boolean type. If this parameter is set to true, the character set type can be changed. This parameter is used together with characterEncoding=CHARSET to set the character set. The two parameters are separated by ampersands (&). - currentSchema: string type. This parameter specifies the schema to be set in search-path. - hostRecheckSeconds: integer type. After JDBC attempts to connect to a host, the host status is saved: connection success or connection failure. This status is trusted within the duration specified by hostRecheckSeconds. After the duration expires, the status becomes invalid. The default value is 10 seconds. - ssl: Boolean type. This parameter specifies a connection in SSL mode.When this parameter is set to true, the NonValidatingFactory channel and certificate mode are supported. 1. For the NonValidatingFactory channel, configure the username and password and set SSL to true. 2. In certification mode, configure the client certificate, key, and root certificate, and set SSL to true. - sslmode: string type. This parameter specifies the SSL authentication mode. The value can be require, verify-ca, or verify-full. - require: The system attempts to set up an SSL connection. If there is a CA file, the system performs verification as if the parameter was set to verify-ca. - verify-ca: The system attempts to set up an SSL connection and checks whether the server certificate is issued by a trusted CA. - verify-full: The system attempts to set up an SSL connection, checks whether the server certificate is issued by a trusted CA, and checks whether the host name of the server is the same as that in the certificate. - sslcert: string type. This parameter specifies the complete path of the certificate file. The type of the client and server certificates is End Entity. - sslkey: string type. This parameter specifies the complete path of the key file. You must run the following command to convert the client certificate to the DER format: openssl pkcs8 -topk8 -outform DER -in client.key -out client.key.pk8 -nocrypt - sslrootcert: string type. This parameter specifies the name of the SSL root certificate. The root certificate type is CA. - sslpassword: string type. This parameter is provided for ConsoleCallbackHandler. - sslpasswordcallback: string type. This parameter specifies the class name of the SSL password provider. The default value is org.postgresql.ssl.jdbc4.LibPQFactory.ConsoleCallbackHandler. - sslfactory: string type. This parameter specifies the class name used by SSLSocketFactory to establish an SSL connection. - sslfactoryarg: string type. The value is an optional parameter of the constructor function of the sslfactory class and is not recommended. - sslhostnameverifier: string type. This parameter specifies the class name of the host name verifier. The interface must implement javax.net.ssl.HostnameVerifier. The default value is org.postgresql.ssl.PGjdbcHostnameVerifier. - loginTimeout: integer type. This parameter specifies the waiting time for establishing the database connection, in seconds.connectTimeout: integer type. This parameter specifies the timeout duration for connecting to a server, in seconds. If the time taken to connect to a server exceeds the value specified, the connection is interrupted. If the value is 0, the timeout mechanism is disabled. - socketTimeout: integer type. This parameter specifies the timeout duration for a socket read operation, in seconds. If the time taken to read data from a server exceeds the value specified, the connection is closed. If the value is 0, the timeout mechanism is disabled. - cancelSignalTimeout: integer type. Cancel messages may cause a block. This parameter controls connectTimeout and socketTimeout in a cancel message, in seconds. The default value is 10 seconds. - tcpKeepAlive: Boolean type. This parameter is used to enable or disable TCP keepalive detection. The default value is false. - logUnclosedConnections: Boolean type. The client may leak a connection object because it does not call the connection object's close() method. These objects will be collected as garbage and finalized using the finalize() method. If the caller ignores this operation, this method closes the connection. - assumeMinServerVersion: string type. The client sends a request to set a floating point. This parameter specifies the version of the server to connect, for example, assumeMinServerVersion=9.0. This parameter can reduce the number of packets to send during connection setup. - ApplicationName: string type. This parameter specifies the name of the JDBC driver that is being connected. You can query the pg_stat_activity table on the primary database node to view information about the client that is being connected. The JDBC driver name is displayed in the application_name column. The default value is PostgreSQL JDBC Driver. - connectionExtraInfo: Boolean type. This parameter specifies whether the JDBC driver reports the driver deployment path and process owner to the database.The value can be true or false. The default value is false. If connectionExtraInfo is set to true, the JDBC driver reports the driver deployment path and process owner to the database and displays the information in the connection_info parameter. In this case, you can query the information from PG_STAT_ACTIVITY. - autosave: string type. The value can be always, never, or conservative. The default value is never. This parameter specifies the action that the driver should perform upon a query failure. If autosave is set to always, the JDBC driver sets a savepoint before each query and rolls back to the savepoint if the query fails. If autosave is set to never, there is no savepoint. If autosave is set to conservative, a savepoint is set for each query. However, the system rolls back and retries only when there is an invalid statement. - protocolVersion: integer type. This parameter specifies the connection protocol version. Only version 3 is supported. Note: MD5 encryption is used when this parameter is set. You must use the following command to change the database encryption mode:gs_guc set -N all -I all -c "password_encryption_type=1". After MogDB is restarted, create a user that uses MD5 encryption to encrypt passwords. You must also change the client connection mode to md5 in the pg_hba.conf file. Log in as the new user (not recommended). - prepareThreshold: integer type. This parameter specifies the time when the parse statement is sent. The default value is 5. It takes a long time to parse an SQL statement for the first time, but a short time to parse SQL statements later because of cache. If a session runs an SQL statement multiple consecutive times and the number of execution times exceeds the value of prepareThreshold, JDBC does not send the parse command to the SQL statement. - preparedStatementCacheQueries: integer type. This parameter specifies the number of queries cached in each connection. The default value is 256. If more than 256 different queries are used in the prepareStatement() call, the least recently used query cache will be discarded. The value 0 indicates that the cache function is disabled. - preparedStatementCacheSizeMiB: integer type. This parameter specifies the maximum cache size of each connection, in MB. The default value is 5. If the size of the cached queries exceeds 5 MB, the least recently used query cache will be discarded. The value 0 indicates that the cache function is disabled. - databaseMetadataCacheFields: integer type. The default value is 65536. This parameter specifies the maximum cache size of each connection. The value 0 indicates that the cache function is disabled. - databaseMetadataCacheFieldsMiB: integer type. The default value is 5. This parameter specifies the maximum cache size of each connection, in MB. The value 0 indicates that the cache function is disabled. - stringtype: string type. The value can be false, unspecified, or varchar. The default value is varchar. This parameter specifies the type of the PreparedStatement parameter used by the setString() method. If stringtype is set to varchar, these parameters are sent to the server as varchar parameters. If stringtype is set to unspecified, these parameters are sent to the server as an untyped value, and the server attempts to infer their appropriate type. - batchMode: Boolean type. This parameter specifies whether to connect the database in batch mode. - fetchsize: integer type. This parameter specifies the default fetchsize for statements in the created connection. - reWriteBatchedInserts: Boolean type. During batch import, this parameter, if set to on, can combine N insertion statements into one: insert into TABLE_NAME values(values1, …, valuesN), …, (values1, …, valuesN). To use this parameter, set batchMode to off. - unknownLength: integer type. The default value is Integer.MAX_VALUE. This parameter specifies the length of the unknown length type when the data of some postgresql types (such as TEXT) is returned by functions such as ResultSetMetaData.getColumnDisplaySize and ResultSetMetaData.getPrecision. - defaultRowFetchSize: integer type. This parameter specifies the number of rows read by fetch in ResultSet at a time. Limiting the number of rows read each time in a database access request can avoid unnecessary memory consumption, thereby avoiding out of memory exception. The default value is 0, indicating that all rows are obtained at a time in ResultSet. There is no negative value. - binaryTransfer: Boolean type. This parameter specifies whether data is sent and received in binary format. The default value is false. - binaryTransferEnable: string type. This parameter specifies the type for which binary transmission is enabled. Every two types are separated by commas (,). You can select either the OID or name, for example, binaryTransferEnable=Integer4_ARRAY,Integer8_ARRAY.For example, if the OID name is BLOB and the OID number is 88, you can configure the OID as follows:binaryTransferEnable=BLOB or binaryTransferEnable=88 - binaryTransferDisEnable: string type. This parameter specifies the type for which binary transmission is disabled. Every two types are separated by commas (,). You can select either the OID or name. The value of this parameter overwrites the value of binaryTransferEnable. - blobMode: string type. This parameter sets the setBinaryStream method to assign values to different types of data. The value on indicates that values are assigned to blob data. The value off indicates that values are assigned to bytea data. The default value is on. - socketFactory: string type. This parameter specifies the name of the class used to create a socket connection with the server. This class must implement the javax.net.SocketFactory interface and define a constructor with no parameter or a single string parameter. - socketFactoryArg: string type. The value is an optional parameter of the constructor function of the socketFactory class and is not recommended. - receiveBufferSize: integer type. This parameter is used to set SO_RCVBUF on the connection stream. - sendBufferSize: integer type. This parameter is used to set SO_SNDBUF on the connection stream. - preferQueryMode: string type. The value can be extended, extendedForPrepared, extendedCacheEverything, or simple. This parameter specifies the query mode. In simple mode, the query is executed without parsing or binding. In extended mode, the query is executed and bound. The extendedForPrepared mode is used for prepared statement extension. In extendedCacheEverything mode, each statement is cached. - targetServerType: string type. The value can be any, master, slave, or preferSlave. |
user | Database user. |
password | Password of the database user. |
Examples
// The following code encapsulates database connection operations into an interface. The database can then be connected using an authorized username and a password.
public static Connection getConnect(String username, String passwd)
{
// Driver class.
String driver = "org.postgresql.Driver";
// Database connection descriptor.
String sourceURL = "jdbc:postgresql://10.10.0.13:8000/postgres";
Connection conn = null;
try
{
// Load the driver.
Class.forName(driver);
}
catch( Exception e )
{
e.printStackTrace();
return null;
}
try
{
// Create a connection.
conn = DriverManager.getConnection(sourceURL, username, passwd);
System.out.println("Connection succeed!");
}
catch(Exception e)
{
e.printStackTrace();
return null;
}
return conn;
};
// The following code uses the Properties object as a parameter to establish a connection.
public static Connection getConnectUseProp(String username, String passwd)
{
// Driver class.
String driver = "org.postgresql.Driver";
// Database connection descriptor.
String sourceURL = "jdbc:postgresql://10.10.0.13:8000/postgres?";
Connection conn = null;
Properties info = new Properties();
try
{
// Load the driver.
Class.forName(driver);
}
catch( Exception e )
{
e.printStackTrace();
return null;
}
try
{
info.setProperty("user", username);
info.setProperty("password", passwd);
// Create a connection.
conn = DriverManager.getConnection(sourceURL, info);
System.out.println("Connection succeed!");
}
catch(Exception e)
{
e.printStackTrace();
return null;
}
return conn;
};