v3.1

About MogDB
- MogDB Introduction
- Comparison Between MogDB and openGauss
- MogDB Release Notes
  - MogDB Release Notes
  - MogDB 3.1.0
- Open Source Components
- Usage Limitations
- Terms of Use
Quick Start
- MogDB Playground
- Container-based MogDB Installation
- Installation on a Single Node
- MogDB Access
  - Use CLI to Access MogDB
    - gsql
    - pgcli
  - Use GUI to Access MogDB
  - Use Middleware to Access MogDB
    - Use WebLogic to Configure MogDB Data Sources
    - Use WebSphere to Configure MogDB Data Sources
  - Use Programming Language to Access MogDB
    - Java
    - C/C++
    - Python
    - Go
    - Rust
    - NodeJS
    - .Net
- Using Sample Dataset Mogila
Characteristic Description
Installation Guide
- Installation Preparation
  - Environment Requirement
  - Operating System Configuration
- Container Installation
- PTK-based Installation
- OM-based Installation
- Manual Installation
- Recommended Parameter Settings
Administrator Guide
AI Features Guide
- AI Features Overview
- AI4DB: Autonomous Database O&M
  - DBMind Mode
  - Components that Support DBMind
    - Prometheus Exporter
  - AI Sub-functions of the DBMind
    - X-Tuner: Parameter Tuning and Diagnosis
    - Index-advisor: Index Recommendation
    - Slow Query Diagnosis: Root Cause Analysis for Slow SQL Statements
    - Forecast: Trend Prediction
    - SQLdiag: Slow SQL Discovery
    - SQL Rewriter
    - Anomaly Detection
- DB4AI: Database-driven AI
  - Native DB4AI Engine
  - Full-process AI
    - PLPython Fenced Mode
    - DB4AI-Snapshots for Data Version Management
- AI in DB
  - Intelligence Explain: SQL Statement Query Time Prediction
- ABO Optimizer
  - Intelligent Cardinality Estimation
  - Adaptive Plan Selection
Security Guide
- Database Security Management
Developer Guide
- Application Development Guide
  - Development Specifications
  - Development Based on JDBC
  - Development Based on ODBC
  - Development Based on libpq
    - Dependent Header Files of libpq
    - Development Process
    - Example
    - Link Parameters
    - libpq API Reference
      - Database Connection Control Functions
        Description
        PQconnectdbParams
        PQconnectdb
        PQconninfoParse
        PQconnectStart
        PQerrorMessage
        PQsetdbLogin
        PQfinish
        PQreset
        PQstatus
      - Database Statement Execution Functions
        PQclear
        PQexec
        PQexecParams
        PQexecParamsBatch
        PQexecPrepared
        PQexecPreparedBatch
        PQfname
        PQgetvalue
        PQnfields
        PQntuples
        PQprepare
        PQresultStatus
      - Functions for Asynchronous Command Processing
        Description
        PQsendQuery
        PQsendQueryParams
        PQsendPrepare
        PQsendQueryPrepared
        PQflush
      - Functions for Canceling Queries in Progress
        PQgetCancel
        PQfreeCancel
        PQcancel
  - Psycopg-Based Development
  - Commissioning
- Stored Procedure
- User Defined Functions
- PL/pgSQL-SQL Procedural Language
  - Overview of PL/pgSQL Functions
  - Data Types
  - Data Type Conversion
  - Arrays and Records
  - DECLARE Syntax
  - Basic Statements
  - Dynamic Statements
  - Control Statements
  - Transaction Management
  - Other Statements
  - Cursors
  - Advanced Packages
    - Basic Interfaces
      - PKG_SERVICE
  - Retry Management
  - Debugging
  - package
- Scheduled Jobs
  - PKG_SERVICE API
- Autonomous Transaction
- Logical Replication
  - Logical Decoding
    - Overview
    - Logical Decoding by SQL Function Interfaces
  - Publication-Subscription
- Extension
  - PostGIS Extension
  - Foreign Data Wrapper
  - orafce
  - pg_bulkload
  - pg_prewarm
  - pg_repack
  - pg_trgm
  - wal2json
  - whale
- Materialized View
  - Materialized View Overview
  - Full Materialized View
  - Incremental Materialized View
- Partition Management
  - Partition Pruning
  - Recommendations For Choosing A Partitioning Strategy
Performance Tuning Guide
Reference Guide
Common Faults and Identification
- Common Fault Locating Methods
- Common Fault Locating Cases
  - Core Fault Locating
  - Permission/Session/Data Type Fault Location
  - Service/High Availability/Concurrency Fault Location
  - Table/Partition Table Fault Location
    - Table Size Does not Change After VACUUM FULL Is Executed on the Table
    - An Error Is Reported When the Table Partition Is Modified
  - File System/Disk/Memory Fault Location
  - SQL Fault Location
  - Index Fault Location
  - CM Two-Node Fault Location
    - Manual Failover
    - Manual Failover for Brain Split
Source Code Parsing
FAQs
Glossary
Communication Matrix
Mogeaver
- Overview
- Release Notes

Comment Information Functions

col_description(table_oid, column_number)

Description: Obtains the comment for a table column.

Return type: text

Note: col_description returns the comment for a table column, which is specified by the OID of its table and its column number.
obj_description(object_oid, catalog_name)

Description: Obtains the comment for a database object.

Return type: text

Note: The two-parameter form of obj_description returns the comment for a database object specified by its OID and the name of the containing system catalog. For example, obj_description(123456,'pg_class') would retrieve the comment for the table with OID 123456. The one-parameter form of obj_description requires only the object OID.

obj_description cannot be used for table columns since columns do not have OIDs of their own.
obj_description(object_oid)

Description: Obtains the comment for a database object.

Return type: text
shobj_description(object_oid, catalog_name)

Description: Obtains the comment for a shared database object.

Return type: text

Note: shobj_description is used just like obj_description except the former is used for retrieving comments on shared objects. Some system catalogs are global to all databases in MogDB, and the comments for objects in them are stored globally as well.