- What's New
- Product Bulletin
- Function Overview
-
Service Overview
- What Is GaussDB(DWS)?
- Data Warehouse Types
- Data Warehouse Flavors
- Advantages
- Application Scenarios
- Functions
- Concepts
- Related Services
- Security
- GaussDB(DWS) Permissions Management
- GaussDB(DWS) Access
- Pricing Details
- Restrictions
- Service Quotas
- Technical Specifications
- Version Description
-
Getting Started
- Checkpoint Vehicle Analysis
- Supply Chain Requirement Analysis of a Company
- Operations Status Analysis of a Retail Department Store
- Creating a Time Series Table
- Best Practices of Hot and Cold Data Management
- Best Practices for Automatic Partition Management
- Creating a Cluster and Connecting to It
- Using CDM to Migrate MySQL Data to the GaussDB(DWS) Cluster
- Using DLI Flink Jobs to Write Kafka Data to GaussDB(DWS) in Real Time
- Basic SQL Operations
-
Database Quick Start
- Before You Start
- Creating and Managing Databases
- Planning a Storage Model
- Creating and Managing Tables
- Loading Sample Data
- Querying System Catalogs
- Creating and Managing Schemas
- Creating and Managing Partitioned Tables
- Creating and Managing Indexes
- Creating and Managing Views
- Creating and Managing Sequences
- Creating and Managing Scheduled Tasks
-
Management Guide
- Process for Using GaussDB(DWS)
- Preparations
- Creating or Deleting a Cluster
-
Cluster Connection
- Methods of Connecting to a Cluster
- Obtaining the Cluster Connection Address
- Using the Data Studio GUI Client to Connect to a Cluster
- Using the gsql CLI Client to Connect to a Cluster
- Using the JDBC and ODBC Drivers to Connect to a Cluster
- Using the Third-Party Function Library psycopg2 of Python to Connect to a Cluster
- Using the Python Library PyGreSQL to Connect to a Cluster
- Managing Database Connections
-
Monitoring and Alarms
- Dashboard
- Databases Monitoring (DMS)
- Monitoring Clusters Using Cloud Eye
-
Alarms
- Alarm Management
- Alarm Rules
- Alarm Subscriptions
-
Alarm Handling
- DWS_2000000001 Node CPU Usage Exceeds the Threshold
- DWS_2000000006 Node Data Disk Usage Exceeds the Threshold
- DWS_2000000009 Node Data Disk I/O Usage Exceeds the Threshold
- DWS_2000000012 Node Data Disk Latency Exceeds the Threshold
- DWS_2000000016 Data Spilled to Disks of the Query Statement Exceeds the Threshold
- DWS_2000000017 Number of Queuing Query Statements Exceeds the Threshold
- DWS_2000000018 Queue Congestion in the Default Cluster Resource Pool
- DWS_2000000020 Long SQL Probe Execution Duration in a Cluster
- DWS_2000000023 A Vacuum Full Operation That Holds a Lock for A Long Time Exists in the Cluster
- Event Notifications
- Specifications Change and Scaling
- Backup and Disaster Recovery
- Intelligent O&M
-
Cluster Management
- Modifying Database Parameters
- Checking the Cluster Status
- Viewing Cluster Details
- Changing a Cluster Name
- O&M Account
- Managing Access Domain Names
- Cluster Topology
- Managing Tags
- Managing Enterprise Projects
- Managing Clusters That Fail to Be Created
- Removing the Read-only Status
- Performing a Primary/Standby Switchback
- Starting and Stopping a Cluster
- Resetting a Password
- Cluster Upgrade
- Associating and Disassociating ELB
- Managing CNs
- Data Integration
- Cluster Log Management
- Database User Management
- Audit Logs
- Cluster Security Management
- Resource Management
- Data Source Management
-
Managing Logical Clusters
- Logical Cluster Overview
- Adding/Deleting a Logical Cluster
- Managing Logical Clusters
- Scheduling GaussDB(DWS) 3.0 Logical Cluster Creation and Deletion
- Tutorial: Converting a Physical Cluster That Contains Data into a Logical Cluster
- Tutorial: Dividing a New Physical Cluster into Logical Clusters
- Tutorial: Setting a Read-Only Logical Cluster and Binding It to a User
-
Best Practices
- Import and Export
-
Data Migration
- Migrating Data From Oracle to GaussDB(DWS)
- Synchronizing MySQL Table Data to GaussDB(DWS) in Real Time
- Using DLI Flink Jobs to Write Kafka Data to GaussDB(DWS) in Real Time
- Practice of Data Interconnection Between Two DWS Clusters Based on GDS
-
Table Optimization Practices
- Table Structure Design
- Table Optimization Overview
- Selecting a Table Model
- Step 1: Creating an Initial Table and Loading Sample Data
- Step 2: Testing System Performance of the Initial Table and Establishing a Baseline
- Step 3: Optimizing a Table
- Step 4: Creating Another Table and Loading Data
- Step 5: Testing System Performance in the New Table
- Step 6: Evaluating the Performance of the Optimized Table
- Appendix: Table Creation Syntax
- Advanced Features
- Database Management
- Sample Data Analysis
- Security Management
-
Data Migration and Synchronization
- Data Migration to GaussDB(DWS)
-
Importing Data
- Importing Data from OBS in Parallel
- Using GDS to Import Data from a Remote Server
- Importing Data from MRS to a Cluster
- Importing Data from One GaussDB(DWS) Cluster to Another
- GDS-based Cross-Cluster Interconnection
- Using a gsql Meta-Command to Import Data
- Running the COPY FROM STDIN Statement to Import Data
- Full Database Migration
- Metadata Migration
- Exporting Data
- Other Operations
-
Developer Guide
-
Standard Data Warehouse (9.1.0.x)
- Before You Start
-
GaussDB(DWS) Development Design Proposal
- Overview
- GaussDB(DWS) Connection Management Specifications
- GaussDB(DWS) Object Design Specifications
- GaussDB(DWS) SQL Statement Development Specifications
- GaussDB(DWS) Stored Procedure Development Specifications
- Detailed Design Rules for GaussDB(DWS) Objects
-
Creating and Managing GaussDB(DWS) Database Objects
- Creating and Managing GaussDB(DWS) Databases
- Creating and Managing GaussDB(DWS) Schemas
- Creating and Managing GaussDB(DWS) Tables
- Selecting a GaussDB(DWS) Table Storage Model
- Creating and Managing GaussDB(DWS) Partitioned Tables
- Creating and Managing GaussDB(DWS) Indexes
- Creating and Using GaussDB(DWS) Sequences
- Creating and Managing GaussDB(DWS) Views
- Creating and Managing GaussDB(DWS) Scheduled Tasks
- Viewing GaussDB(DWS) System Catalogs
- Syntax Compatibility Differences Among Oracle, Teradata, and MySQL
- GaussDB(DWS) Database Security Management
- GaussDB(DWS) Data Query
- GaussDB(DWS) Sorting Rules
- GaussDB(DWS) User-Defined Functions
-
GaussDB(DWS) Stored Procedure
- Overview
- Converting Data Types in GaussDB(DWS) Stored Procedures
- GaussDB(DWS) Stored Procedure Array and Record
- GaussDB(DWS) Stored Procedure Declaration Syntax
- Basic Statements of GaussDB(DWS) Stored Procedures
- Dynamic Statements of GaussDB(DWS) Stored Procedures
- GaussDB(DWS) Stored Procedure Control Statements
- Other Statements in a GaussDB(DWS) Stored Procedure
- GaussDB(DWS) Stored Procedure Cursor
- GaussDB(DWS) Stored Procedure Advanced Package
- GaussDB(DWS) Stored Procedure Debugging
- Using PostGIS Extension
- Using JDBC or ODBC for GaussDB(DWS) Secondary Development
- GaussDB(DWS) Resource Monitoring
-
GaussDB(DWS) Performance Tuning
- Overview
- Performance Diagnosis
- System Optimization
-
SQL Tuning
- SQL Query Execution Process
- SQL Execution Plan
- Execution Plan Operator
- SQL Tuning Process
- Updating Statistics
- Reviewing and Modifying a Table Definition
- Advanced SQL Tuning
- Configuring Optimizer Parameters
- Hint-based Tuning
- Routinely Maintaining Tables
- Routinely Recreating an Index
- Automatic Retry upon SQL Statement Execution Errors
- Query Band Load Identification
-
SQL Tuning Examples
- Case: Selecting an Appropriate Distribution Column
- Case: Creating an Appropriate Index
- Case: Adding NOT NULL for JOIN Columns
- Case: Pushing Down Sort Operations to DNs
- Case: Configuring cost_param for Better Query Performance
- Case: Adjusting the Partial Clustering Key
- Case: Adjusting the Table Storage Mode in a Medium Table
- Case: Reconstructing Partition Tables
- Case: Adjusting the GUC Parameter best_agg_plan
- Case: Rewriting SQL Statements and Eliminating Prune Interference
- Case: Rewriting SQL Statements and Deleting in-clause
- Case: Setting Partial Cluster Keys
- Case: Converting from NOT IN to NOT EXISTS
-
GaussDB(DWS) System Catalogs and Views
- Overview of System Catalogs and System Views
-
System Catalogs
- GS_BLOCKLIST_QUERY
- GS_BLOCKLIST_SQL
- GS_OBSSCANINFO
- GS_RESPOOL_RESOURCE_HISTORY
- GS_WLM_INSTANCE_HISTORY
- GS_WLM_OPERATOR_INFO
- GS_WLM_SESSION_INFO
- GS_WLM_USER_RESOURCE_HISTORY
- PG_AGGREGATE
- PG_AM
- PG_AMOP
- PG_AMPROC
- PG_ATTRDEF
- PG_ATTRIBUTE
- PG_AUTHID
- PG_AUTH_HISTORY
- PG_AUTH_MEMBERS
- PG_BLOCKLISTS
- PG_CAST
- PG_CLASS
- PG_COLLATION
- PG_CONSTRAINT
- PG_CONVERSION
- PG_DATABASE
- PG_DB_ROLE_SETTING
- PG_DEFAULT_ACL
- PG_DEPEND
- PG_DESCRIPTION
- PG_ENUM
- PG_EXCEPT_RULE
- PG_EXTENSION
- PG_EXTENSION_DATA_SOURCE
- PG_FINE_DR_INFO
- PG_FOREIGN_DATA_WRAPPER
- PG_FOREIGN_SERVER
- PG_FOREIGN_TABLE
- PG_INDEX
- PG_INHERITS
- PG_JOB_INFO
- PG_JOBS
- PG_LANGUAGE
- PG_LARGEOBJECT
- PG_LARGEOBJECT_METADATA
- PG_MATVIEW
- PG_NAMESPACE
- PG_OBJECT
- PG_OBSSCANINFO
- PG_OPCLASS
- PG_OPERATOR
- PG_OPFAMILY
- PG_PARTITION
- PG_PLTEMPLATE
- PG_PROC
- PG_PUBLICATION
- PG_PUBLICATION_NAMESPACE
- PG_PUBLICATION_REL
- PG_RANGE
- PG_REDACTION_COLUMN
- PG_REDACTION_POLICY
- PG_RELFILENODE_SIZE
- PG_RLSPOLICY
- PG_RESOURCE_POOL
- PG_REWRITE
- PG_SECLABEL
- PG_SHDEPEND
- PG_SHDESCRIPTION
- PG_SHSECLABEL
- PG_STATISTIC
- PG_STATISTIC_EXT
- PG_STAT_OBJECT
- PG_SUBSCRIPTION
- 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_ACTION
- PGXC_CLASS
- PGXC_GROUP
- PGXC_NODE
- PLAN_TABLE_DATA
- SNAPSHOT
- TABLES_SNAP_TIMESTAMP
- System Catalogs for Performance View Snapshot
-
System Views
- ALL_ALL_TABLES
- ALL_CONSTRAINTS
- ALL_CONS_COLUMNS
- ALL_COL_COMMENTS
- ALL_DEPENDENCIES
- ALL_IND_COLUMNS
- ALL_IND_EXPRESSIONS
- ALL_INDEXES
- ALL_OBJECTS
- ALL_PROCEDURES
- ALL_SEQUENCES
- ALL_SOURCE
- ALL_SYNONYMS
- ALL_TAB_COLUMNS
- ALL_TAB_COMMENTS
- ALL_TABLES
- ALL_USERS
- ALL_VIEWS
- DBA_DATA_FILES
- DBA_USERS
- DBA_COL_COMMENTS
- DBA_CONSTRAINTS
- DBA_CONS_COLUMNS
- DBA_IND_COLUMNS
- DBA_IND_EXPRESSIONS
- DBA_IND_PARTITIONS
- DBA_INDEXES
- DBA_OBJECTS
- DBA_PART_INDEXES
- DBA_PART_TABLES
- DBA_PROCEDURES
- DBA_SEQUENCES
- DBA_SOURCE
- DBA_SYNONYMS
- DBA_TAB_COLUMNS
- DBA_TAB_COMMENTS
- DBA_TAB_PARTITIONS
- DBA_TABLES
- DBA_TABLESPACES
- DBA_TRIGGERS
- DBA_VIEWS
- DUAL
- GET_ALL_TSC_INFO
- GET_TSC_INFO
- GLOBAL_COLUMN_TABLE_IO_STAT
- GLOBAL_REDO_STAT
- GLOBAL_REL_IOSTAT
- GLOBAL_ROW_TABLE_IO_STAT
- GLOBAL_STAT_DATABASE
- GLOBAL_TABLE_CHANGE_STAT
- GLOBAL_TABLE_STAT
- GLOBAL_WORKLOAD_SQL_COUNT
- GLOBAL_WORKLOAD_SQL_ELAPSE_TIME
- GLOBAL_WORKLOAD_TRANSACTION
- GS_ALL_CONTROL_GROUP_INFO
- GS_BLOCKLIST_QUERY
- GS_BLOCKLIST_SQL
- GS_CLUSTER_RESOURCE_INFO
- GS_COLUMN_TABLE_IO_STAT
- GS_OBS_READ_TRAFFIC
- GS_OBS_WRITE_TRAFFIC
- GS_INSTR_UNIQUE_SQL
- GS_NODE_STAT_RESET_TIME
- GS_OBS_LATENCY
- GS_QUERY_MONITOR
- GS_QUERY_RESOURCE_INFO
- GS_REL_IOSTAT
- GS_RESPOOL_RUNTIME_INFO
- GS_RESPOOL_RESOURCE_INFO
- GS_RESPOOL_MONITOR
- GS_ROW_TABLE_IO_STAT
- GS_SESSION_CPU_STATISTICS
- GS_SESSION_MEMORY_STATISTICS
- GS_SQL_COUNT
- GS_STAT_DB_CU
- GS_STAT_SESSION_CU
- GS_TABLE_CHANGE_STAT
- GS_TABLE_STAT
- GS_TOTAL_NODEGROUP_MEMORY_DETAIL
- GS_USER_MONITOR
- GS_USER_TRANSACTION
- GS_VIEW_DEPENDENCY
- GS_VIEW_DEPENDENCY_PATH
- GS_VIEW_INVALID
- GS_WAIT_EVENTS
- GS_WLM_OPERAROR_INFO
- GS_WLM_OPERATOR_HISTORY
- GS_WLM_OPERATOR_STATISTICS
- GS_WLM_SESSION_INFO
- GS_WLM_SESSION_HISTORY
- GS_WLM_SESSION_STATISTICS
- GS_WLM_SQL_ALLOW
- GS_WORKLOAD_SQL_COUNT
- GS_WORKLOAD_SQL_ELAPSE_TIME
- GS_WORKLOAD_TRANSACTION
- MPP_TABLES
- PG_AVAILABLE_EXTENSION_VERSIONS
- PG_AVAILABLE_EXTENSIONS
- PG_BULKLOAD_STATISTICS
- PG_COMM_CLIENT_INFO
- PG_COMM_DELAY
- PG_COMM_STATUS
- PG_COMM_RECV_STREAM
- PG_COMM_SEND_STREAM
- PG_COMM_QUERY_SPEED
- PG_CONTROL_GROUP_CONFIG
- PG_CURSORS
- PG_EXT_STATS
- PG_GET_INVALID_BACKENDS
- PG_GET_SENDERS_CATCHUP_TIME
- PG_GROUP
- PG_INDEXES
- PG_JOB
- PG_JOB_PROC
- PG_JOB_SINGLE
- PG_LIFECYCLE_DATA_DISTRIBUTE
- PG_LOCKS
- PG_LWLOCKS
- PG_NODE_ENV
- PG_OS_THREADS
- PG_POOLER_STATUS
- PG_PREPARED_STATEMENTS
- PG_PREPARED_XACTS
- PG_PUBLICATION_TABLES
- PG_QUERYBAND_ACTION
- PG_REPLICATION_SLOTS
- PG_ROLES
- PG_RULES
- PG_RUNNING_XACTS
- PG_SECLABELS
- PG_SEQUENCES
- PG_SESSION_WLMSTAT
- PG_SESSION_IOSTAT
- PG_SETTINGS
- PG_SHADOW
- PG_SHARED_MEMORY_DETAIL
- 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_GET_MEM_MBYTES_RESERVED
- 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_THREAD_WAIT_STATUS
- PG_TABLES
- PG_TDE_INFO
- PG_TIMEZONE_ABBREVS
- PG_TIMEZONE_NAMES
- PG_TOTAL_MEMORY_DETAIL
- PG_TOTAL_SCHEMA_INFO
- PG_TOTAL_USER_RESOURCE_INFO
- PG_USER
- PG_USER_MAPPINGS
- PG_VIEWS
- PG_WLM_STATISTICS
- PGXC_AIO_RESOURCE_POOL_STATS
- PGXC_BULKLOAD_PROGRESS
- PGXC_BULKLOAD_INFO
- PGXC_BULKLOAD_STATISTICS
- PGXC_COLUMN_TABLE_IO_STAT
- PGXC_COMM_CLIENT_INFO
- PGXC_COMM_DELAY
- PGXC_COMM_RECV_STREAM
- PGXC_COMM_SEND_STREAM
- PGXC_COMM_STATUS
- PGXC_COMM_QUERY_SPEED
- PGXC_DEADLOCK
- PGXC_DISK_CACHE_STATS
- PGXC_DISK_CACHE_ALL_STATS
- PGXC_DISK_CACHE_PATH_INFO
- PGXC_GET_STAT_ALL_TABLES
- PGXC_GET_STAT_ALL_PARTITIONS
- PGXC_GET_TABLE_SKEWNESS
- PGXC_GTM_SNAPSHOT_STATUS
- PGXC_INSTANCE_TIME
- PGXC_LOCKWAIT_DETAIL
- PGXC_INSTR_UNIQUE_SQL
- PGXC_LOCK_CONFLICTS
- PGXC_LWLOCKS
- PGXC_MEMORY_DEBUG_INFO
- PGXC_NODE_ENV
- PGXC_NODE_STAT_RESET_TIME
- PGXC_OBS_IO_SCHEDULER_STATS
- PGXC_OBS_IO_SCHEDULER_PERIODIC_STATS
- PGXC_OS_RUN_INFO
- PGXC_OS_THREADS
- PGXC_POOLER_STATUS
- PGXC_PREPARED_XACTS
- PGXC_REDO_STAT
- PGXC_REL_IOSTAT
- PGXC_REPLICATION_SLOTS
- PGXC_RESPOOL_RUNTIME_INFO
- PGXC_RESPOOL_RESOURCE_INFO
- PGXC_RESPOOL_RESOURCE_HISTORY
- PGXC_ROW_TABLE_IO_STAT
- PGXC_RUNNING_XACTS
- PGXC_SETTINGS
- PGXC_SESSION_WLMSTAT
- PGXC_STAT_ACTIVITY
- PGXC_STAT_BAD_BLOCK
- PGXC_STAT_BGWRITER
- PGXC_STAT_DATABASE
- PGXC_STAT_OBJECT
- PGXC_STAT_REPLICATION
- PGXC_STAT_TABLE_DIRTY
- PGXC_STAT_WAL
- PGXC_SQL_COUNT
- PGXC_TABLE_CHANGE_STAT
- PGXC_TABLE_STAT
- PGXC_THREAD_WAIT_STATUS
- PGXC_TOTAL_MEMORY_DETAIL
- PGXC_TOTAL_SCHEMA_INFO
- PGXC_TOTAL_SCHEMA_INFO_ANALYZE
- PGXC_TOTAL_USER_RESOURCE_INFO
- PGXC_USER_TRANSACTION
- PGXC_VARIABLE_INFO
- PGXC_WAIT_DETAIL
- PGXC_WAIT_EVENTS
- PGXC_WLM_OPERATOR_HISTORY
- PGXC_WLM_OPERATOR_INFO
- PGXC_WLM_OPERATOR_STATISTICS
- PGXC_WLM_SESSION_INFO
- PGXC_WLM_SESSION_HISTORY
- PGXC_WLM_SESSION_STATISTICS
- PGXC_WLM_TABLE_DISTRIBUTION_SKEWNESS
- PGXC_WLM_USER_RESOURCE_HISTORY
- PGXC_WLM_WORKLOAD_RECORDS
- PGXC_WORKLOAD_SQL_COUNT
- PGXC_WORKLOAD_SQL_ELAPSE_TIME
- PGXC_WORKLOAD_TRANSACTION
- PLAN_TABLE
- PV_FILE_STAT
- PV_INSTANCE_TIME
- PV_MATVIEW_DETAIL
- PV_OS_RUN_INFO
- PV_SESSION_MEMORY
- PV_SESSION_MEMORY_DETAIL
- PV_SESSION_STAT
- PV_SESSION_TIME
- PV_TOTAL_MEMORY_DETAIL
- PV_REDO_STAT
- PV_RUNTIME_ATTSTATS
- PV_RUNTIME_RELSTATS
- REDACTION_COLUMNS
- REDACTION_POLICIES
- REMOTE_TABLE_STAT
- SHOW_TSC_INFO
- SHOW_ALL_TSC_INFO
- USER_COL_COMMENTS
- USER_CONSTRAINTS
- USER_CONS_COLUMNS
- USER_INDEXES
- USER_IND_COLUMNS
- USER_IND_EXPRESSIONS
- USER_IND_PARTITIONS
- USER_JOBS
- USER_OBJECTS
- USER_PART_INDEXES
- USER_PART_TABLES
- USER_PROCEDURES
- USER_SEQUENCES
- USER_SOURCE
- USER_SYNONYMS
- USER_TAB_COLUMNS
- USER_TAB_COMMENTS
- USER_TAB_PARTITIONS
- USER_TABLES
- USER_TRIGGERS
- USER_VIEWS
- V$SESSION
- V$SESSION_LONGOPS
-
GUC Parameters of the GaussDB(DWS) Database
- Viewing GUC Parameters
- Configuring GUC Parameters
- GUC Parameter Usage
- Connection and Authentication
- Resource Consumption
- Parallel Data Import
- Write Ahead Logs
- HA Replication
- Query Planning
- Error Reporting and Logging
- Alarm Detection
- Statistics During the Database Running
- Resource Management
- Automatic Cleanup
- Default Settings of Client Connection
- Lock Management
- Version and Platform Compatibility
- Fault Tolerance
- Connection Pool Parameters
- Cluster Transaction Parameters
- Developer Operations
- Auditing
- Transaction Monitoring
- GTM Parameters
- Miscellaneous Parameters
- GaussDB(DWS) Developer Terms
-
Standard Data Warehouse (8.1.3.x)
- Before You Start
-
GaussDB(DWS) Development Design Specifications
- Overview
- GaussDB(DWS) Connection Management Specifications
- GaussDB(DWS) Object Design Specifications
- GaussDB(DWS) SQL Statement Development Specifications
- GaussDB(DWS) Stored Procedure Development Specifications
- Detailed Design Rules for GaussDB(DWS) Objects
-
Creating and Managing GaussDB(DWS) Database Objects
- Creating and Managing GaussDB(DWS) Databases
- Creating and Managing GaussDB(DWS) Schemas
- Selecting a GaussDB(DWS) Table Storage Model
- Creating and Managing GaussDB(DWS) Tables
- Creating and Managing GaussDB(DWS) Partitioned Tables
- Creating and Managing GaussDB(DWS) Indexes
- Creating and Using GaussDB(DWS) Sequences
- Creating and Managing GaussDB(DWS) Views
- Creating and Managing GaussDB(DWS) Scheduled Tasks
- Viewing GaussDB(DWS) System Catalogs
- Syntax Compatibility Differences Among Oracle, Teradata, and MySQL
- GaussDB(DWS) Database Security Management
- GaussDB(DWS) Data Query
- GaussDB(DWS) Sorting Rules
- GaussDB(DWS) User-Defined Functions
-
GaussDB(DWS) Stored Procedure
- Overview
- Converting Data Types in GaussDB(DWS) Stored Procedures
- GaussDB(DWS) Stored Procedure Array and Record
- GaussDB(DWS) Stored Procedure Declaration Syntax
- Basic Statements of GaussDB(DWS) Stored Procedures
- Dynamic Statements of GaussDB(DWS) Stored Procedures
- GaussDB(DWS) Stored Procedure Control Statements
- Other Statements in a GaussDB(DWS) Stored Procedure
- GaussDB(DWS) Stored Procedure Cursor
- GaussDB(DWS) Stored Procedure Advanced Package
- GaussDB(DWS) Stored Procedure Debugging
- Using PostGIS Extension
- Using JDBC or ODBC for GaussDB(DWS) Secondary Development
- GaussDB(DWS) Resource Monitoring
-
GaussDB(DWS) Performance Tuning
- Overview
- Performance Diagnosis
- System Optimization
-
SQL Tuning
- SQL Query Execution Process
- SQL Execution Plan
- Execution Plan Operator
- SQL Tuning Process
- Updating Statistics
- Reviewing and Modifying a Table Definition
- Advanced SQL Tuning
- Hint-based Tuning
- Routinely Maintaining Tables
- Routinely Recreating an Index
- Automatic Retry upon SQL Statement Execution Errors
- query_band Load Identification
-
SQL Tuning Examples
- Case: Selecting an Appropriate Distribution Column
- Case: Creating an Appropriate Index
- Case: Adding NOT NULL for JOIN Columns
- Case: Pushing Down Sort Operations to DNs
- Case: Configuring cost_param for Better Query Performance
- Case: Adjusting the Partial Clustering Key
- Case: Adjusting the Table Storage Mode in a Medium Table
- Case: Reconstructing Partition Tables
- Case: Adjusting the GUC Parameter best_agg_plan
- Case: Rewriting SQL Statements and Eliminating Prune Interference
- Case: Rewriting SQL Statements and Deleting in-clause
- Case: Setting Partial Cluster Keys
- Case: Converting from NOT IN to NOT EXISTS
-
GaussDB(DWS) System Catalogs and Views
- Overview of System Catalogs and System Views
-
System Catalogs
- GS_OBSSCANINFO
- GS_RESPOOL_RESOURCE_HISTORY
- GS_WLM_INSTANCE_HISTORY
- GS_WLM_OPERATOR_INFO
- GS_WLM_SESSION_INFO
- GS_WLM_USER_RESOURCE_HISTORY
- PG_AGGREGATE
- PG_AM
- PG_AMOP
- PG_AMPROC
- 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_ENUM
- PG_EXTENSION
- PG_EXTENSION_DATA_SOURCE
- PG_FOREIGN_DATA_WRAPPER
- PG_FOREIGN_SERVER
- PG_FOREIGN_TABLE
- PG_INDEX
- PG_INHERITS
- PG_JOBS
- PG_LANGUAGE
- PG_LARGEOBJECT
- PG_LARGEOBJECT_METADATA
- PG_NAMESPACE
- PG_OBJECT
- PG_OBSSCANINFO
- PG_OPCLASS
- PG_OPERATOR
- PG_OPFAMILY
- PG_PARTITION
- PG_PLTEMPLATE
- PG_PROC
- PG_RANGE
- PG_REDACTION_COLUMN
- PG_REDACTION_POLICY
- PG_RELFILENODE_SIZE
- PG_RLSPOLICY
- PG_RESOURCE_POOL
- PG_REWRITE
- 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_ACTION
- PGXC_CLASS
- PGXC_GROUP
- PGXC_NODE
- PLAN_TABLE_DATA
- SNAPSHOT
- TABLES_SNAP_TIMESTAMP
- System Catalogs for Performance View Snapshot
-
System Views
- ALL_ALL_TABLES
- ALL_CONSTRAINTS
- ALL_CONS_COLUMNS
- ALL_COL_COMMENTS
- ALL_DEPENDENCIES
- ALL_IND_COLUMNS
- ALL_IND_EXPRESSIONS
- ALL_INDEXES
- ALL_OBJECTS
- ALL_PROCEDURES
- ALL_SEQUENCES
- ALL_SOURCE
- ALL_SYNONYMS
- ALL_TAB_COLUMNS
- ALL_TAB_COMMENTS
- ALL_TABLES
- ALL_USERS
- ALL_VIEWS
- DBA_DATA_FILES
- DBA_USERS
- DBA_COL_COMMENTS
- DBA_CONSTRAINTS
- DBA_CONS_COLUMNS
- DBA_IND_COLUMNS
- DBA_IND_EXPRESSIONS
- DBA_IND_PARTITIONS
- DBA_INDEXES
- DBA_OBJECTS
- DBA_PART_INDEXES
- DBA_PART_TABLES
- DBA_PROCEDURES
- DBA_SEQUENCES
- DBA_SOURCE
- DBA_SYNONYMS
- DBA_TAB_COLUMNS
- DBA_TAB_COMMENTS
- DBA_TAB_PARTITIONS
- DBA_TABLES
- DBA_TABLESPACES
- DBA_TRIGGERS
- DBA_VIEWS
- DUAL
- GLOBAL_COLUMN_TABLE_IO_STAT
- GLOBAL_REDO_STAT
- GLOBAL_REL_IOSTAT
- GLOBAL_ROW_TABLE_IO_STAT
- GLOBAL_STAT_DATABASE
- GLOBAL_TABLE_CHANGE_STAT
- GLOBAL_TABLE_STAT
- GLOBAL_WORKLOAD_SQL_COUNT
- GLOBAL_WORKLOAD_SQL_ELAPSE_TIME
- GLOBAL_WORKLOAD_TRANSACTION
- GS_ALL_CONTROL_GROUP_INFO
- GS_CLUSTER_RESOURCE_INFO
- GS_COLUMN_TABLE_IO_STAT
- GS_INSTR_UNIQUE_SQL
- GS_NODE_STAT_RESET_TIME
- GS_REL_IOSTAT
- GS_RESPOOL_RUNTIME_INFO
- GS_RESPOOL_RESOURCE_INFO
- GS_ROW_TABLE_IO_STAT
- GS_SESSION_CPU_STATISTICS
- GS_SESSION_MEMORY_STATISTICS
- GS_SQL_COUNT
- GS_STAT_DB_CU
- GS_STAT_SESSION_CU
- GS_TABLE_CHANGE_STAT
- GS_TABLE_STAT
- GS_TOTAL_NODEGROUP_MEMORY_DETAIL
- GS_USER_TRANSACTION
- GS_VIEW_DEPENDENCY
- GS_VIEW_DEPENDENCY_PATH
- GS_VIEW_INVALID
- GS_WAIT_EVENTS
- GS_WLM_OPERAROR_INFO
- GS_WLM_OPERATOR_HISTORY
- GS_WLM_OPERATOR_STATISTICS
- GS_WLM_SESSION_INFO
- GS_WLM_SESSION_HISTORY
- GS_WLM_SESSION_STATISTICS
- GS_WLM_SQL_ALLOW
- GS_WORKLOAD_SQL_COUNT
- GS_WORKLOAD_SQL_ELAPSE_TIME
- GS_WORKLOAD_TRANSACTION
- MPP_TABLES
- PG_AVAILABLE_EXTENSION_VERSIONS
- PG_AVAILABLE_EXTENSIONS
- PG_BULKLOAD_STATISTICS
- PG_COMM_CLIENT_INFO
- PG_COMM_DELAY
- PG_COMM_STATUS
- PG_COMM_RECV_STREAM
- PG_COMM_SEND_STREAM
- PG_COMM_QUERY_SPEED
- PG_CONTROL_GROUP_CONFIG
- PG_CURSORS
- PG_EXT_STATS
- PG_GET_INVALID_BACKENDS
- PG_GET_SENDERS_CATCHUP_TIME
- PG_GROUP
- PG_INDEXES
- PG_JOB
- PG_JOB_PROC
- PG_JOB_SINGLE
- PG_LIFECYCLE_DATA_DISTRIBUTE
- PG_LOCKS
- PG_NODE_ENV
- PG_OS_THREADS
- PG_POOLER_STATUS
- PG_PREPARED_STATEMENTS
- PG_PREPARED_XACTS
- PG_QUERYBAND_ACTION
- PG_REPLICATION_SLOTS
- PG_ROLES
- PG_RULES
- PG_RUNNING_XACTS
- PG_SECLABELS
- PG_SESSION_WLMSTAT
- PG_SESSION_IOSTAT
- PG_SETTINGS
- PG_SHADOW
- PG_SHARED_MEMORY_DETAIL
- 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_GET_MEM_MBYTES_RESERVED
- 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_THREAD_WAIT_STATUS
- PG_TABLES
- PG_TDE_INFO
- PG_TIMEZONE_ABBREVS
- PG_TIMEZONE_NAMES
- PG_TOTAL_MEMORY_DETAIL
- PG_TOTAL_SCHEMA_INFO
- PG_TOTAL_USER_RESOURCE_INFO
- PG_USER
- PG_USER_MAPPINGS
- PG_VIEWS
- PG_WLM_STATISTICS
- PGXC_BULKLOAD_PROGRESS
- PGXC_BULKLOAD_STATISTICS
- PGXC_COLUMN_TABLE_IO_STAT
- PGXC_COMM_CLIENT_INFO
- PGXC_COMM_DELAY
- PGXC_COMM_RECV_STREAM
- PGXC_COMM_SEND_STREAM
- PGXC_COMM_STATUS
- PGXC_COMM_QUERY_SPEED
- PGXC_DEADLOCK
- PGXC_GET_STAT_ALL_TABLES
- PGXC_GET_STAT_ALL_PARTITIONS
- PGXC_GET_TABLE_SKEWNESS
- PGXC_GTM_SNAPSHOT_STATUS
- PGXC_INSTANCE_TIME
- PGXC_LOCKWAIT_DETAIL
- PGXC_INSTR_UNIQUE_SQL
- PGXC_LOCK_CONFLICTS
- PGXC_NODE_ENV
- PGXC_NODE_STAT_RESET_TIME
- PGXC_OS_RUN_INFO
- PGXC_OS_THREADS
- PGXC_PREPARED_XACTS
- PGXC_REDO_STAT
- PGXC_REL_IOSTAT
- PGXC_REPLICATION_SLOTS
- PGXC_RESPOOL_RUNTIME_INFO
- PGXC_RESPOOL_RESOURCE_INFO
- PGXC_RESPOOL_RESOURCE_HISTORY
- PGXC_ROW_TABLE_IO_STAT
- PGXC_RUNNING_XACTS
- PGXC_SETTINGS
- PGXC_SESSION_WLMSTAT
- PGXC_STAT_ACTIVITY
- PGXC_STAT_BAD_BLOCK
- PGXC_STAT_BGWRITER
- PGXC_STAT_DATABASE
- PGXC_STAT_REPLICATION
- PGXC_STAT_TABLE_DIRTY
- PGXC_SQL_COUNT
- PGXC_TABLE_CHANGE_STAT
- PGXC_TABLE_STAT
- PGXC_THREAD_WAIT_STATUS
- PGXC_TOTAL_MEMORY_DETAIL
- PGXC_TOTAL_SCHEMA_INFO
- PGXC_TOTAL_SCHEMA_INFO_ANALYZE
- PGXC_USER_TRANSACTION
- PGXC_VARIABLE_INFO
- PGXC_WAIT_DETAIL
- PGXC_WAIT_EVENTS
- PGXC_WLM_OPERATOR_HISTORY
- PGXC_WLM_OPERATOR_INFO
- PGXC_WLM_OPERATOR_STATISTICS
- PGXC_WLM_SESSION_INFO
- PGXC_WLM_SESSION_HISTORY
- PGXC_WLM_SESSION_STATISTICS
- PGXC_WLM_WORKLOAD_RECORDS
- PGXC_WORKLOAD_SQL_COUNT
- PGXC_WORKLOAD_SQL_ELAPSE_TIME
- PGXC_WORKLOAD_TRANSACTION
- PLAN_TABLE
- PV_FILE_STAT
- PV_INSTANCE_TIME
- PV_OS_RUN_INFO
- PV_SESSION_MEMORY
- PV_SESSION_MEMORY_DETAIL
- PV_SESSION_STAT
- PV_SESSION_TIME
- PV_TOTAL_MEMORY_DETAIL
- PV_REDO_STAT
- REDACTION_COLUMNS
- REDACTION_POLICIES
- REMOTE_TABLE_STAT
- USER_COL_COMMENTS
- USER_CONSTRAINTS
- USER_CONS_COLUMNS
- USER_INDEXES
- USER_IND_COLUMNS
- USER_IND_EXPRESSIONS
- USER_IND_PARTITIONS
- USER_JOBS
- USER_OBJECTS
- USER_PART_INDEXES
- USER_PART_TABLES
- USER_PROCEDURES
- USER_SEQUENCES
- USER_SOURCE
- USER_SYNONYMS
- USER_TAB_COLUMNS
- USER_TAB_COMMENTS
- USER_TAB_PARTITIONS
- USER_TABLES
- USER_TRIGGERS
- USER_VIEWS
- V$SESSION
- V$SESSION_LONGOPS
-
GUC Parameters of the GaussDB(DWS) Database
- Viewing GUC Parameters
- Configuring GUC Parameters
- GUC Parameter Usage
- Connection and Authentication
- Resource Consumption
- Parallel Data Import
- Write Ahead Logs
- HA Replication
- Query Planning
- Error Reporting and Logging
- Alarm Detection
- Statistics During the Database Running
- Resource Management
- Automatic Cleanup
- Default Settings of Client Connection
- Lock Management
- Version and Platform Compatibility
- Fault Tolerance
- Connection Pool Parameters
- Cluster Transaction Parameters
- Developer Operations
- Auditing
- Transaction Monitoring
- GTM Parameters
- Miscellaneous Parameters
- GaussDB(DWS) Developer Terms
-
Standard Data Warehouse (9.1.0.x)
-
SQL Syntax Reference
-
SQL Syntax Reference (9.1.0.x)
- GaussDB(DWS) SQL Overview
- Differences Between GaussDB(DWS) and PostgreSQL
- Keyword
-
Data Types
- Numeric Types
- Monetary Types
- Boolean Type
- Character Types
- Binary Data Types
- Date/Time Types
- Geometric Types
- Array
- Enumeration Type
- Network Address Types
- Bit String Types
- Text Search Types
- UUID Type
- JSON Types
- RoaringBitmap
- HLL Data Types
- Object Identifier Types
- Pseudo-Types
- Range Types
- Composite Types
- Data Types Supported by Column-Store Tables
- XML
- Constant and Macro
-
Functions and Operators
- Character Processing Functions and Operators
- Binary String Functions and Operators
- Bit String Functions and Operators
- Numeric Functions and Operators
- Date and Time Processing Functions and Operators
- SEQUENCE Functions
- Array Functions and Operators
- Logical Operators
- Comparison Operators
- Pattern Matching Operators
- Aggregate Functions
- Window Functions
- Type Conversion Functions
- JSON/JSONB Functions and Operators
- Security Functions
- Conditional Expression Functions
- Range Functions and Operators
- Data Redaction Functions
- Bitmap Functions and Operators
- UUID Functions
- Text Search Functions and Operators
- HLL Functions and Operators
- Set Returning Functions
- Geometric Functions and Operators
- Network Address Functions and Operators
- System Information Functions
- System Administration Functions
- Backup and Restoration Control Functions
- Database Object Functions
- Residual File Management Functions
- Statistics Information Functions
- Trigger Functions
- XML Functions
- Call Stack Recording Functions
- Hudi System Functions
- Funnel and Retention Functions
- EXTERNAL SCHEMA System Functions
- Storage-Compute Decoupling Functions
- Expressions
- Type Conversion
- Full Text Search
- System Operation
- Transaction Management
-
DDL Syntax
- DDL Syntax Overview
- ALTER BLOCK RULE
- ALTER DATABASE
- ALTER EXCEPT RULE
- ALTER FOREIGN TABLE (GDS Import and Export)
- ALTER FOREIGN TABLE (for HDFS or OBS)
- ALTER FOREIGN TABLE (SQL on other GaussDB(DWS))
- ALTER FUNCTION
- ALTER GROUP
- ALTER INDEX
- ALTER LARGE OBJECT
- ALTER MATERIALIZED VIEW
- ALTER PUBLICATION
- ALTER REDACTION POLICY
- ALTER RESOURCE POOL
- ALTER ROLE
- ALTER SUBSCRIPTION
- ALTER ROW LEVEL SECURITY POLICY
- ALTER SCHEMA
- ALTER SEQUENCE
- ALTER SERVER
- ALTER SESSION
- ALTER SYNONYM
- ALTER SYSTEM KILL SESSION
- ALTER TABLE
- ALTER TABLE PARTITION
- ALTER TEXT SEARCH CONFIGURATION
- ALTER TEXT SEARCH DICTIONARY
- ALTER TRIGGER
- ALTER TYPE
- ALTER USER
- ALTER VIEW
- CLEAN CONNECTION
- CLOSE
- CLUSTER
- COMMENT
- CREATE BARRIER
- CREATE BLOCK RULE
- CREATE DATABASE
- CREATE EXCEPT RULE
- CREATE FOREIGN TABLE (for GDS Import and Export)
- CREATE FOREIGN TABLE (SQL on OBS or Hadoop)
- CREATE FOREIGN TABLE (for OBS Import and Export)
- CREATE FOREIGN TABLE (SQL on other GaussDB(DWS))
- CREATE FUNCTION
- CREATE GROUP
- CREATE INDEX
- CREATE MATERIALIZED VIEW
- CREATE PROCEDURE
- CREATE PUBLICATION
- CREATE REDACTION POLICY
- CREATE ROW LEVEL SECURITY POLICY
- CREATE RESOURCE POOL
- CREATE ROLE
- CREATE SCHEMA
- CREATE SEQUENCE
- CREATE SERVER
- CREATE SUBSCRIPTION
- CREATE SYNONYM
- CREATE TABLE
- CREATE TABLE AS
- CREATE TABLE PARTITION
- CREATE TEXT SEARCH CONFIGURATION
- CREATE TEXT SEARCH DICTIONARY
- CREATE TRIGGER
- CREATE TYPE
- CREATE USER
- CREATE VIEW
- CURSOR
- DISCARD
- DROP BLOCK RULE
- DROP DATABASE
- DROP EXCEPT RULE
- DROP FOREIGN TABLE
- DROP FUNCTION
- DROP GROUP
- DROP INDEX
- DROP MATERIALIZED VIEW
- DROP OWNED
- DROP PUBLICATION
- DROP REDACTION POLICY
- DROP ROW LEVEL SECURITY POLICY
- DROP PROCEDURE
- DROP RESOURCE POOL
- DROP ROLE
- DROP SCHEMA
- DROP SEQUENCE
- DROP SERVER
- DROP SUBSCRIPTION
- DROP SYNONYM
- DROP TABLE
- DROP TEXT SEARCH CONFIGURATION
- DROP TEXT SEARCH DICTIONARY
- DROP TRIGGER
- DROP TYPE
- DROP USER
- DROP VIEW
- FETCH
- MOVE
- REFRESH MATERIALIZED VIEW
- REINDEX
- RENAME TABLE
- RESET
- SET
- SET CONSTRAINTS
- SET ROLE
- SET SESSION AUTHORIZATION
- SHOW
- TRUNCATE
- VACUUM
- DML Syntax
- DCL Syntax
- DQL Syntax
- TCL Syntax
-
SQL Syntax Reference (8.1.3.x)
- GaussDB(DWS) SQL Overview
- Differences Between GaussDB(DWS) and PostgreSQL
- Keyword
-
Data Types
- Numeric Types
- Monetary Types
- Boolean Type
- Character Types
- Binary Data Types
- Date/Time Types
- Geometric Types
- Array
- Enumeration Type
- Network Address Types
- Bit String Types
- Text Search Types
- UUID Type
- JSON Types
- RoaringBitmap
- HLL Data Types
- Object Identifier Types
- Pseudo-Types
- Range Types
- Composite Types
- Data Types Supported by Column-Store Tables
- XML
- Constant and Macro
-
Functions and Operators
- Character Processing Functions and Operators
- Binary String Functions and Operators
- Bit String Functions and Operators
- Mathematical Functions and Operators
- Date and Time Processing Functions and Operators
- SEQUENCE Functions
- Array Functions and Operators
- Logical Operators
- Comparison Operators
- Pattern Matching Operators
- Aggregate Functions
- Window Functions
- Type Conversion Functions
- JSON/JSONB Functions and Operators
- Security Functions
- Conditional Expression Functions
- Range Functions and Operators
- Data Masking Functions
- Roaring Bitmap Functions and Operators
- UUID Functions
- Text Search Functions and Operators
- HLL Functions and Operators
- Set Returning Functions
- Geometric Functions and Operators
- Network Address Functions and Operators
- System Information Functions
- System Administration Functions
- Database Object Functions
- Residual File Management Functions
- Statistics Information Functions
- Trigger Functions
- XML Functions
- Call Stack Recording Functions
- Expressions
- Type Conversion
- Full Text Search
- System Operation
- Transaction Management
-
DDL Syntax
- DDL Syntax Overview
- ALTER DATABASE
- ALTER FOREIGN TABLE (GDS Import and Export)
- ALTER FOREIGN TABLE (for HDFS or OBS)
- ALTER FOREIGN TABLE (SQL on other GaussDB(DWS))
- ALTER FUNCTION
- ALTER GROUP
- ALTER INDEX
- ALTER LARGE OBJECT
- ALTER REDACTION POLICY
- ALTER RESOURCE POOL
- ALTER ROLE
- ALTER ROW LEVEL SECURITY POLICY
- ALTER SCHEMA
- ALTER SEQUENCE
- ALTER SERVER
- ALTER SESSION
- ALTER SYNONYM
- ALTER SYSTEM KILL SESSION
- ALTER TABLE
- ALTER TABLE PARTITION
- ALTER TEXT SEARCH CONFIGURATION
- ALTER TEXT SEARCH DICTIONARY
- ALTER TRIGGER
- ALTER TYPE
- ALTER USER
- ALTER VIEW
- CLEAN CONNECTION
- CLOSE
- CLUSTER
- COMMENT
- CREATE BARRIER
- CREATE DATABASE
- CREATE FOREIGN TABLE (for GDS Import and Export)
- CREATE FOREIGN TABLE (SQL on OBS or Hadoop)
- CREATE FOREIGN TABLE (for OBS Import and Export)
- CREATE FOREIGN TABLE (SQL on other GaussDB(DWS))
- CREATE FUNCTION
- CREATE GROUP
- CREATE INDEX
- CREATE REDACTION POLICY
- CREATE ROW LEVEL SECURITY POLICY
- CREATE PROCEDURE
- CREATE RESOURCE POOL
- CREATE ROLE
- CREATE SCHEMA
- CREATE SEQUENCE
- CREATE SERVER
- CREATE SYNONYM
- CREATE TABLE
- CREATE TABLE AS
- CREATE TABLE PARTITION
- CREATE TEXT SEARCH CONFIGURATION
- CREATE TEXT SEARCH DICTIONARY
- CREATE TRIGGER
- CREATE TYPE
- CREATE USER
- CREATE VIEW
- CURSOR
- DROP DATABASE
- DROP FOREIGN TABLE
- DROP FUNCTION
- DROP GROUP
- DROP INDEX
- DROP OWNED
- DROP REDACTION POLICY
- DROP ROW LEVEL SECURITY POLICY
- DROP PROCEDURE
- DROP RESOURCE POOL
- DROP ROLE
- DROP SCHEMA
- DROP SEQUENCE
- DROP SERVER
- DROP SYNONYM
- DROP TABLE
- DROP TEXT SEARCH CONFIGURATION
- DROP TEXT SEARCH DICTIONARY
- DROP TRIGGER
- DROP TYPE
- DROP USER
- DROP VIEW
- FETCH
- MOVE
- REINDEX
- RENAME TABLE
- RESET
- SET
- SET CONSTRAINTS
- SET ROLE
- SET SESSION AUTHORIZATION
- SHOW
- TRUNCATE
- VACUUM
- DML Syntax
- DCL Syntax
- DQL Syntax
- TCL Syntax
-
SQL Syntax Reference (9.1.0.x)
-
Performance Tuning
- Overview of Query Performance Optimization
- Query Analysis
- Query Improvement
-
Optimization Cases
- Case: Selecting an Appropriate Distribution Column
- Case: Creating an Appropriate Index
- Case: Adding NOT NULL for JOIN Columns
- Case: Pushing Down Sort Operations to DNs
- Case: Configuring cost_param for Better Query Performance
- Case: Adjusting the Distribution Key
- Case: Adjusting the Partial Clustering Key
- Case: Adjusting the Table Storage Mode in a Medium Table
- Case: Adjusting the Local Clustering Column
- Case: Reconstructing Partition Tables
- Case: Adjusting the GUC Parameter best_agg_plan
- Case: Rewriting SQL and Deleting Subqueries (Case 1)
- Case: Rewriting SQL and Deleting Subqueries (Case 2)
- Case: Rewriting SQL Statements and Eliminating Prune Interference
- Case: Rewriting SQL Statements and Deleting in-clause
- Case: Setting Partial Cluster Keys
- SQL Execution Troubleshooting
- query_band Load Identification
-
Tool Guide
- Overview
- Downloading Client Tools
- gsql - CLI Client
-
Data Studio - Integrated Database Development Tool
- About Data Studio
- Installing and Configuring Data Studio
- Quick Start
- Data Studio GUI
- Data Studio Menus
- Data Studio Toolbar
- Data Studio Right-Click Menus
- Connection Profiles
- Databases
- Schemas
- Creating a Function/Procedure
- Editing a Function/Procedure
- Granting/Revoking a Permission (Function/Procedure)
- Debugging a PL/SQL Function
- Working with Functions/Procedures
- GaussDB(DWS) Tables
- Sequences
- Views
- Users/Roles
-
SQL Terminal
- Opening Multiple SQL Terminal Tabs
- Managing the SQL Query Execution History
- Opening and Saving SQL Scripts
- Viewing Object Properties in the SQL Terminal
- Canceling the Execution of SQL Queries
- Formatting of SQL Queries
- Selecting a DB Object in the SQL Terminal
- Viewing the Query Execution Plan and Cost
- Viewing the Query Execution Plan and Cost Graphically
- Working with SQL Terminals
- Exporting Query Results
- Managing SQL Terminal Connections
- Batch Operation
- Personalizing Data Studio
- Performance Specifications
- Security Management
- Troubleshooting
- FAQs
- GDS: Parallel Data Loader
-
DSC: SQL Syntax Migration Tool
- Overview
- Supported Keywords and Features
- Constraints and Limitations
- System Requirements
- Installing DSC
- Configuring DSC
- Using DSC
- Teradata Syntax Migration
-
Oracle Syntax Migration
- Overview
- Schema Objects
- COMPRESS Phrase
- Bitmap Index
- Custom Tablespace
- Supplemental Log Data
- LONG RAW
- SYS_GUID
- DML
- Pseudo Columns
- OUTER JOIN
- OUTER QUERY (+)
- CONNECT BY
- System Functions
- PL/SQL
- PL/SQL Collections (Using User-Defined Types)
- PL/SQL Packages
- VARRAY
- Granting Execution Permissions
- Package Name List
- Data Type
- Chinese Character Support
- Netezza Syntax Migration
- MySQL Syntax Migration
- DB2 Syntax Migration
- Command Reference
- Log Reference
- Troubleshooting
- FAQs
- Security Management
- DWS-Connector
- Server Tool
- API Reference
-
FAQs
-
General Problems
- Why Are Data Warehouses Necessary?
- What Are the Differences Between a Data Warehouse and the Hadoop Big Data Platform?
- Why Should I Use Public Cloud GaussDB(DWS)?
- Should I Choose Public Cloud GaussDB(DWS) or RDS?
- When Should I Use GaussDB(DWS) and MRS?
- What Is the User Quota?
- What Are the Differences Between Users and Roles?
- How Do I Check the Creation Time of a Database User?
- Regions and AZs
- Is My Data Secure in GaussDB(DWS)?
- How Is GaussDB(DWS) Secured?
- Can I Modify the Security Group of a GaussDB(DWS) Cluster?
- How Are LibrA, GaussDB A, and GaussDB(DWS) Related?
- What Is a Database/Data Warehouse/Data Lake/Lakehouse?
-
Cluster Management
- What Do I Do If Creating a GaussDB(DWS) Cluster Failed?
- How Can I Clear and Reclaim the Storage Space?
- Can I Switch My Cluster Nodes to Another Region After Purchase?
- Why Did the Used Storage Shrink After Scale-out?
- How Do I View Node Metrics (CPU, Memory, and Disk Usage)?
- Does GaussDB(DWS) Support BMS?
- How Is the Disk Space or Capacity of GaussDB(DWS) Calculated?
- What Are the gaussdb and postgres Databases of GaussDB(DWS)?
- How Do I Set the Maximum Number of Sessions When Adding an Alarm Rule on Cloud Eye?
- What Should I Do If the Scale-out Check Fails?
- When Should I Add CNs or Scale out a cluster?
- What Are the Scenarios of Resizing a Cluster, Changing the Node Flavor, Scale-out, and Scale-in?
- How Should I Select from a Small-Flavor Many-Node Cluster and a Large-Flavor Three-Node Cluster with Same CPU Cores and Memory?
- What Are the Differences Between Cloud SSDs and Local SSDs?
- What Are the Differences Between Hot Data Storage and Cold Data Storage?
-
Database Connections
- How Applications Communicate with GaussDB(DWS)?
- Does GaussDB(DWS) Support Third-Party Clients and JDBC and ODBC Drivers?
- Can I Connect to GaussDB(DWS) Cluster Nodes Using SSH?
- What Should I Do If I Cannot Connect to a Data Warehouse Cluster?
- Why Was I Not Notified of Failure Unbinding the EIP When GaussDB(DWS) Is Connected Over the Internet?
- How Do I Configure a Whitelist to Protect Clusters Available Through a Public IP Address?
-
Data Import and Export
- What Are the Differences Between Data Formats Supported by OBS and GDS Foreign Tables?
- How Do I Import Incremental Data Using an OBS Foreign Table?
- How Can I Import Data to GaussDB(DWS)?
- How Much Service Data Can a Data Warehouse Store?
- How Do I Use \Copy to Import and Export Data?
- How Do I Implement Fault Tolerance Import Between Different Encoding Libraries
- Can I Import and Export Data to and from OBS Across Regions?
- How Do I Import GaussDB(DWS)/Oracle/MySQL/SQL Server Data to GaussDB(DWS) (Whole Database Migration)?
- Can I Import Data over the Public/External Network Using GDS?
- Which Are the Factors That Affect GaussDB(DWS) Import Performance?
-
Account, Password, and Permissions
- How Does GaussDB(DWS) Implement Workload Isolation?
- How Do I Change the Password of a Database Account When the Password Expires?
- How Do I Grant Table Permissions to a User?
- How Do I Grant Schema Permissions to a User?
- How Do I Create a Database Read-only User?
- How Do I Create Private Database Users and Tables?
- How Do I Revoke the CONNECT ON DATABASE Permission from a User?
- How Do I View the Table Permissions of a User?
- Who Is User Ruby?
-
Database Usage
- How Do I Change Distribution Columns?
- How Do I View and Set the Database Character Encoding?
- What Do I Do If Date Type Is Automatically Converted to the Timestamp Type During Table Creation?
- Do I Need to Run VACUUM FULL and ANALYZE on Common Tables Periodically?
- Do I Need to Set a Distribution Key After Setting a Primary Key?
- Is GaussDB(DWS) Compatible with PostgreSQL Stored Procedures?
- What Are Partitioned Tables, Partitions, and Partition Keys?
- How Can I Export the Table Structure?
- How Can I Delete Table Data Efficiently?
- How Do I View Foreign Table Information?
- If No Distribution Column Is Specified, How Will Data Be Stored?
- How Do I Replace the Null Result with 0?
- How Do I Check Whether a Table Is Row-Stored or Column-Stored?
- How Do I Query the Information About GaussDB(DWS) Column-Store Tables?
- Why Sometimes the GaussDB(DWS) Query Indexes Become Invalid?
- How Do I Use a User-Defined Function to Rewrite the CRC32() Function?
- What Are the Schemas Starting with pg_toast_temp* or pg_temp*?
- Solutions to Inconsistent GaussDB(DWS) Query Results
- Which System Catalogs That the VACUUM FULL Operation Cannot Be Performed on?
- In Which Scenarios Would a Statement Be "idle in transaction"?
- How Does GaussDB(DWS) Implement Row-to-Column and Column-to-Row Conversion?
- What Are the Differences Between Unique Constraints and Unique Indexes?
-
Database Performance
- Why Is SQL Execution Slow After Long GaussDB(DWS) Usage?
- Why Does GaussDB(DWS) Perform Worse Than a Single-Server Database in Extreme Scenarios?
- How Can I View SQL Execution Records in a Certain Period When Read and Write Requests Are Blocked?
- What Do I Do If My Cluster Is Unavailable Because of Insufficient Space?
- What is Operator Spilling in GaussDB(DWS)?
- GaussDB(DWS) CPU Resource Management
- Why the Tasks Executed by an Ordinary User Are Slower Than That Executed by the dbadmin User?
- What Are the Factors Related to the Single-Table Query Performance in GaussDB(DWS)?
- Snapshot Backup and Restoration
-
Billing
- How Do I Renew the Service?
- Is Refund Supported?
- How Am I Billed for Scheduled Synchronization of GaussDB(DWS) Data to a PostgreSQL Database?
- How Can I Try Out GaussDB(DWS) for Free?
- Why Was I Deducted Fees After My GaussDB(DWS) Free Trial Expired?
- Why Can't I See a Cluster After I Subscribe to a Free GaussDB(DWS) Trial?
- How Can I Stop GaussDB(DWS) Billing?
- Does Pay-per-Use Billing Stop When My Cluster Stops?
- Why Is the Purchase Button Unavailable When I Create a Cluster?
- How Do I Unfreeze a Cluster?
- Can I Freeze or Shut Down a GaussDB(DWS) Cluster to Stop Billing?
-
General Problems
-
Troubleshooting
-
Database Connections
- What Do I Do If gsql: command not found Is Displayed When I Run gsql to Connect to the Database?
- Database Cannot Be Connected Using the gsql Client
- An Error Indicating Too Many Client Connections Is Reported When a User Connects to a GaussDB(DWS) Database
- Cluster IP Address Cannot Be Pinged/Accessed
- Error "An I/O error occurred while sending to the backend" Is Reported During Service Execution
- JDBC/ODBC
-
Data Import and Export
- "ERROR: invalid byte sequence for encoding 'UTF8': 0x00" Is Reported When Data Is Imported to GaussDB(DWS) Using COPY FROM
- Data Import and Export Faults with GDS
- Failed to Create a GDS Foreign Table and An Error Is Reported Indicating that ROUNDROBIN Is Not Supported
- When CDM Is Used to Import MySQL Data to GaussDB(DWS), the Column Length Exceeds the Threshold and Data Synchronization Fails
- "Access Denied" Is Displayed When the SQL Statement for Creating an OBS Foreign Table Is Executed
- Disk Usage Increases After Data Fails to Be Imported Using GDS
- Error Message "out of memory" Is Displayed When GDS Is Used to Import Data
- Error Message "connection failure error" Is Displayed During GDS Data Transmission
- Data to Be Imported Contains Chinese When the DataArts Studio Service Is Used to Create a GaussDB(DWS) Foreign Table
- Database Parameter Modification
-
Account/Permission/Password
- How Do I Unlock an Account?
- Account Still Locked After Password Resetting
- After the Permission for Querying Tables in a Schema Is Granted to a User, the User Still Cannot Query the Tables
- How Do I Revoke the Permission of a User If grant select on table t1 to public Has Been Executed on a Table
- An Error Message Is Displayed When a Common User Executes the Statement for Creating or Deleting a GDS or OBS Foreign Table, Indicating that the User Does Not Have the Permission or the Permission Is Insufficient
- After the all Permission Is Granted to the Schema of a User, the Error Message "ERROR: current user does not have privilege to role tom" Persists During Table Creation
- An Error Message Is Reported During Statement Execution, Indicating that the User Does Not Have the Required Permission
- Failed to Run the create extension Command and An Error Indicating No Permission Is Reported
- A User Cannot Be Deleted Due to Its Dependencies
-
Cluster Performance
- Lock Wait Detection
- During SQL Execution, a Table Deadlock Occurs and An Error Stating LOCK_WAIT_TIMEOUT Is Reported
- Error "abort transaction due to concurrent update" Is Reported During SQL Execution
- Solution to High Disk Usage and Cluster Read-Only
- SQL Execution Is Slow with Low Performance and Sometimes Does Not End After a Long Period of Time
- Data Skew Causes Slow SQL Statement Execution and Operations Fail on Large Tables
- Table Size Does not Change After VACUUM FULL Is Executed on the Table
- VACUUM Is Executed After Table Data Deletion, But the Space Is Not Released
- Error LOCK_WAIT_TIMEOUT Is Reported When VACUUM FULL Is Executed
- VACUUM FULL Is Slow
- Table Bloating Causes Slow SQL Query and Failed Data Loading on the GUI
- Memory Overflow Occurs in a Cluster
- Statements with User-defined Functions Cannot Be Pushed Down
- Column-Store Tables Cannot Be Updated or Table Bloat Occurs
- Table Bloat Occurs After Data Is Inserted into a Column-Store Table for Multiple Times
- Writing Data to GaussDB(DWS) Is Slow and Client Data Is Stacked
- Low Query Efficiency
- Poor Query Performance Due to the Lack of Statistics
- Execution of SQL Statements with NOT IN and NOT EXISTS Is Slow Due to Nested Loops in Execution Plans
- SQL Query Is Slow Because Partitions Are Not Pruned
- Optimizer Uses Nested Loop Due to the Small Estimated Number of Rows and the Performance Deteriorates
- SQL Statements Contain the in Constant and No Result Is Returned After SQL Statement Execution
- Performance of Single-Table Point Query Is Poor
- CCN Queuing Under Dynamic Load Management
- Performance Deterioration Due to Data Bloat
- Slow Performance Caused by Too Many Small CUs in Column Storage
- Cluster Exceptions
-
Database Use
- An Error Is Reported When Data Is Inserted or Updated, Indicating that the Distribution Key Cannot Be Updated
- "Connection reset by peer" Is Displayed When a User Executes an SQL Statement
- "value too long for type character varying" Is Displayed When VARCHAR(n) Stores Chinese Characters
- Case Sensitivity in SQL Statements
- cannot drop table test because other objects depend on it Is Displayed When a Table Is Deleted
- Failed to Execute MERGE INTO UPDATE for Multiple Tables
- JDBC Error Occurs Due to session_timeout Settings
- DROP TABLE Fails to Be Executed
- Execution Results of the string_agg Function Are Inconsistent
- Error "could not open relation with OID xxxx" Is Reported During Table Size Query
- DROP TABLE IF EXISTS Syntax Errors
- 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
- An Error Is Reported During SQL Statement Execution, Indicating that the Schema Exists
- Failed to Delete a Database and an Error Is Reported Indicating that a Session Is Connected to the Database
- Byte Type Is Returned After a Table Column of the Character Type Is Read in Java
- "ERROR:start value of partition 'XX' NOT EQUAL up-boundary of last partition." Is Displayed When Operations Related to Table Partitions Are Performed
- Reindexing Fails
- A View Failed to Be Queried
- Global SQL Query
- How Do I Check Whether a Table Has Been Updated or Deleted?
- "Can't fit xid into page" Is Reported
- "unable to get a stable set of rows in the source table" Is Reported
- DWS Metadata Inconsistency - Abnormal Partition Index
- An Error Is Reported When the truncate Command Is Executed on the System Table pg_catalog.gs_wlm_session_info
- "inserted partition key does not map to any table partition" Is Reported When Data Is Inserted into a Partitioned Table
- Error upper boundary of adding partition MUST overtop last existing partition Is Reported When a New Partition Is Added to a Range Partitioned Table
- Error Reported During Table Query: "missing chunk number %d for toast value %u in pg_toast_XXXX"
- When Inserting Data Into a Table, An Error Is Reported: "duplicate key value violates unique constraint "%s""
- Error could not determine which collation to use for string hashing Reported During Service Execution
- When the ODBC Driver of GaussDB(DWS) Is Used, Content of Fields of the Character Type in the SQL Query Result Is Truncated
- Execution Plan Scan Hints Do Not Take Effect
- Error "invalid input syntax for xxx" Is Reported During Data Type Conversion
- Error UNION types %s and %s cannot be matched Is Reported
- "ERROR: Non-deterministic UPDATE" Is Reported During Update
- Error Reported During Data Insertion: null value in column ' %s' violates not-null constraint
- Error "unable to get a stable set of rows in the source table"
- Query Results Are Inconsistent in Oracle, Teradata, and MySQL Compatibility Modes
-
Database Connections
- Videos
-
Error Code Reference
- Management Console Error Code
-
Data Warehouse Service Error Codes
- 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-04901 -- GAUSS-04999
- GAUSS-05101 -- GAUSS-05200
- GAUSS-05201 -- GAUSS-05800
- GAUSS-05801 -- GAUSS-05900
- GAUSS-05901 -- GAUSS-05999
- GAUSS-06101 -- GAUSS-06200
- GAUSS-50000 -- GAUSS-50999
- GAUSS-51000 -- GAUSS-51999
- GAUSS-52000 -- GAUSS-52999
- GAUSS-53000 -- GAUSS-53999
- OE000
-
Technical White Paper
- GaussDB(DWS)
- Platforms and Technical Specifications Supported by GaussDB(DWS)
-
GaussDB(DWS) Core Technologies
- Shared-Nothing Architecture
- Data Distribution in a Distributed System
- Fully Parallel Query
- Vectorized Executor and Hybrid Row-Column Storage Engine
- Resource Monitoring and Management
- Distributed Transactions
- Online Scale-Out
- SQL on Anywhere
- Cluster Management and HA
- SQL Self-Diagnosis
- Transparent Data Encryption
- Data Masking
- Data Backup and Disaster Recovery
- GaussDB(DWS) Tools
- External APIs
GaussDB(DWS) PL/Java Functions
With the GaussDB(DWS) PL/Java functions, you can choose your favorite Java IDE to write Java methods and install the JAR files containing these methods into the GaussDB(DWS) database before invoking them. GaussDB(DWS) PL/Java is developed based on open-source PL/Java 1.5.5 and uses JRE 1.8.0_322.
Constraints
Java UDF can be used for some Java logical computing. You are not advised to encapsulate services in Java UDF.
- You are not advised to connect to a database in any way (for example, JDBC) in Java functions.
- Currently, only data types listed in Table 1 are supported. Other data types, such as user-defined data types and complex data types (for example, Java array and its derived types) are not supported.
- Currently, UDAF and UDTF are not supported.
Examples
Before using PL/Java, you need to pack the implementation of Java methods into a JAR package and deploy it into the database. Then, create functions as a database administrator. For compatibility purposes, use JRE 1.8.0_322 for compilation.
- Compile a JAR package.
Java method implementation and JAR package archiving can be achieved in an integrated development environment (IDE). The following is a simple example of compilation and archiving through command lines. You can create a JAR package that contains a single method in the similar way.
First, prepare an Example.java file that contains a method for converting substrings to uppercase. In the following example, Example is the class name and upperString is the method name:
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public class Example { public static String upperString (String text, int beginIndex, int endIndex) { return text.substring(beginIndex, endIndex).toUpperCase(); } }
Then, create a manifest.txt file containing the following content:
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Manifest-Version: 1.0 Main-Class: Example Specification-Title: "Example" Specification-Version: "1.0" Created-By: 1.6.0_35-b10-428-11M3811 Build-Date: 08/14/2018 10:09 AM
Manifest-Version specifies the version of the manifest file. Main-Class specifies the main class used by the .jar file. Specification-Title and Specification-Version are the extended attributes of the package. Specification-Title specifies the title of the extended specification and Specification-Version specifies the version of the extended specification. Created-By specifies the person who created the file. Build-Date specifies the date when the file was created.
Finally, archive the .java file and package it into javaudf-example.jar.
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javac Example.java jar cfm javaudf-example.jar manifest.txt Example.class
NOTICE:
JAR package names must comply with JDK rules. If a name contains invalid characters, an error occurs when a function is deployed or used.
- Deploy the JAR package.
Place the JAR package on the OBS server using the method described in For details, see "Uploading a File" in Object Storage Service Console Operation Guide.. Then, create the AK/SK. For details about how to obtain the AK/SK, see section Creating Access Keys (AK and SK). Log in to the database and run the gs_extend_library function to import the file to GaussDB(DWS).
1
SELECT gs_extend_library('addjar', 'obs://bucket/path/javaudf-example.jar accesskey=access_key_value_to_be_replaced secretkey=secret_access_key_value_to_be_replaced region=region_name libraryname=example');
For details about how to use the gs_extend_library function, see Manage JAR packages and files. Change the values of AK and SK as needed. Replace region_name with an actual region name.
- Use a PL/Java function.
Log in to the database as a user who has the sysadmin permission (for example, dbadmin) and create the java_upperstring function:
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CREATE FUNCTION java_upperstring(VARCHAR, INTEGER, INTEGER) RETURNS VARCHAR AS 'Example.upperString' LANGUAGE JAVA;
NOTE:
- The data type defined in the java_upperstring function should be a type in GaussDB(DWS) and match the data type defined in 1 in the upperString method in Java. For details about the mapping between GaussDB(DWS) and Java data types, see Table 1.
- The AS clause specifies the class name and static method name of the Java method invoked by the function. The format is Class name.Method name. The class name and method name must match the Java class and method defined in 1.
- To use PL/Java functions, set LANGUAGE to JAVA.
- For details about CREATE FUNCTION, see Create functions.
Execute the java_upperstring function.
1
SELECT java_upperstring('test', 0, 1);
The expected result is as follows:
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java_upperstring --------------------- T (1 row)
- Authorize a common user to use the PL/Java function.
Create a common user named udf_user.
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CREATE USER udf_user PASSWORD 'password';
This command grants user udf_user the permission for the java_upperstring function. Note that the user can use this function only if it also has the permission for using the schema of the function.
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GRANT ALL PRIVILEGES ON SCHEMA public TO udf_user; GRANT ALL PRIVILEGES ON FUNCTION java_upperstring(VARCHAR, INTEGER, INTEGER) TO udf_user;
Log in to the database as user udf_user.
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SET SESSION SESSION AUTHORIZATION udf_user PASSWORD 'password';
Execute the java_upperstring function.
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SELECT public.java_upperstring('test', 0, 1);
The expected result is as follows:
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java_upperstring --------------------- T (1 row)
- Delete the function.
If you no longer need this function, delete it.
1
DROP FUNCTION java_upperstring;
- Uninstall the JAR package.
Use the gs_extend_library function to uninstall the JAR package.
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SELECT gs_extend_library('rmjar', 'libraryname=example');
SQL Definition and Usage
- Manage JAR packages and files.
A database user having the sysadmin permission can use the gs_extend_library function to deploy, view, and delete JAR packages in the database. The syntax of the function is as follows:
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SELECT gs_extend_library('[action]', '[operation]');
NOTE:
- action: operation action. The options are as follows:
- ls: Displays JAR packages in the database and checks the MD5 value consistency of files on each node.
- addjar: deploys a JAR package on the OBS server in the database.
- rmjar: Deletes JAR packages from the database.
- operation: operation string. The format can be either of the following:
obs://[bucket]/[source_filepath] accesskey=[accesskey] secretkey=[secretkey] region=[region] libraryname=[libraryname]
- bucket: name of the bucket to which the OBS file belongs. It is mandatory.
- source_filepath: file path on the OBS server. Only .jar files are supported.
- accesskey: key obtained for accessing the OBS service. It is mandatory.
- secret_key: secret key obtained for the OBS service. It is mandatory.
- region: region where the OBS bucket stored in the JAR package of a user-defined function belongs to. This parameter is mandatory.
- libraryname: user-defined library name, which is used to invoke JAR files in GaussDB(DWS). If action is set to addjar or rmjar, libraryname must be specified. If action is set to ls, libraryname is optional. Note that a user-defined library name cannot contain the following characters: /|;&$<>\'{}"()[]~*?!
- action: operation action. The options are as follows:
- Create functions.
PL/Java functions can be created using the CREATE FUNCTION syntax and are defined as LANGUAGE JAVA, including the RETURNS and AS clauses.
- To use CREATE FUNCTION, specify the name and parameter type for the function to be created.
- The RETURNS clause specifies the return type for the function.
- The AS clause specifies the class name and static method name of the Java method to be invoked. If the NULL value needs to be transferred to the Java method as an input parameter, specify the name of the Java encapsulation class corresponding to the parameter type. For details, see NULL Handling.
- For details about the syntax, see CREATE FUNCTION.
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CREATE [ OR REPLACE ] FUNCTION function_name ( [ { argname [ argmode ] argtype [ { DEFAULT | := | = } expression ]} [, ...] ]) [ RETURNS rettype [ DETERMINISTIC ] ] LANGAUGE JAVA [ { IMMUTABLE | STABLE | VOLATILE } | [ NOT ] LEAKPROOF | WINDOW | { CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT |STRICT } | {[ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER | AUTHID DEFINER | AUTHID CURRENT_USER} | { FENCED } | COST execution_cost | ROWS result_rows | SET configuration_parameter { {TO |=} value | FROM CURRENT} ] [...] { AS 'class_name.method_name' ( { argtype } [, ...] ) }
- Use functions.
During execution, PL/Java searches for the Java class specified by a function among all the deployed JAR packages, which are ranked by name in alphabetical order, invokes the Java method in the first found class, and returns results.
- Delete functions.
PL/Java functions can be deleted by using the DROP FUNCTION syntax. For details about the syntax, see DROP FUNCTION.
DROP FUNCTION [ IF EXISTS ] function_name [ ( [ {[ argmode ] [ argname ] argtype} [, ...] ] ) [ CASCADE | RESTRICT ] ];
To delete an overloaded function (for details, see Overloaded Functions), specify argtype in the function. To delete other functions, simply specify function_name.
- Authorize permissions for functions.
Only user sysadmin can create PL/Java functions. It can also grant other users the permission to use the PL/Java functions. For details about the syntax, see GRANT.
GRANT { EXECUTE | ALL [ PRIVILEGES ] } ON { FUNCTION {function_name ( [ {[ argmode ] [ arg_name ] arg_type} [, ...] ] )} [, ...] | ALL FUNCTIONS IN SCHEMA schema_name [, ...] } TO { [ GROUP ] role_name | PUBLIC } [, ...] [ WITH GRANT OPTION ];
Mapping for Basic Data Types
GaussDB(DWS) |
Java |
---|---|
BOOLEAN |
boolean |
"char" |
byte |
bytea |
byte[] |
SMALLINT |
short |
INTEGER |
int |
BIGINT |
long |
FLOAT4 |
float |
FLOAT8 |
double |
CHAR |
java.lang.String |
VARCHAR |
java.lang.String |
TEXT |
java.lang.String |
name |
java.lang.String |
DATE |
java.sql.Timestamp |
TIME |
java.sql.Time (stored value treated as local time) |
TIMETZ |
java.sql.Time |
TIMESTAMP |
java.sql.Timestamp |
TIMESTAMPTZ |
java.sql.Timestamp |
Array Type Processing
GaussDB(DWS) can convert basic array types. You only need to append a pair of square brackets ([]) to the data type when creating a function.
CREATE FUNCTION java_arrayLength(INTEGER[]) RETURNS INTEGER AS 'Example.getArrayLength' LANGUAGE JAVA;
Java code is similar to the following:
public class Example { public static int getArrayLength(Integer[] intArray) { return intArray.length; } }
Invoke the following statement:
SELECT java_arrayLength(ARRAY[1, 2, 3]);
The expected result is as follows:
java_arrayLength --------------------- 3 (1 row)
NULL Handling
NULL values cannot be handled for GaussDB(DWS) data types that are mapped and can be converted to simple Java types by default. If you use a Java function to obtain and process the NULL value transferred from GaussDB(DWS), specify the Java encapsulation class in the AS clause as follows:
CREATE FUNCTION java_countnulls(INTEGER[]) RETURNS INTEGER AS 'Example.countNulls(java.lang.Integer[])' LANGUAGE JAVA;
Java code is similar to the following:
public class Example { public static int countNulls(Integer[] intArray) { int nullCount = 0; for (int idx = 0; idx < intArray.length; ++idx) { if (intArray[idx] == null) nullCount++; } return nullCount; } }
Invoke the following statement:
SELECT java_countNulls(ARRAY[null, 1, null, 2, null]);
The expected result is as follows:
java_countNulls -------------------- 3 (1 row)
Overloaded Functions
PL/Java supports overloaded functions. You can create functions with the same name or invoke overloaded functions from Java code. The procedure is as follows:
- Create overloaded functions.
For example, create two Java methods with the same name, and specify the methods dummy(int) and dummy(String) with different parameter types.
public class Example { public static int dummy(int value) { return value*2; } public static String dummy(String value) { return value; } }
In addition, create two functions with the same names as the above two functions in GaussDB(DWS).
CREATE FUNCTION java_dummy(INTEGER) RETURNS INTEGER AS 'Example.dummy' LANGUAGE JAVA; CREATE FUNCTION java_dummy(VARCHAR) RETURNS VARCHAR AS 'Example.dummy' LANGUAGE JAVA;
- Invoke the overloaded functions.
GaussDB(DWS) invokes the functions that match the specified parameter type. The results of invoking the above two functions are as follows:
SELECT java_dummy(5); java_dummy ----------------- 10 (1 row) SELECT java_dummy('5'); java_dummy --------------- 5 (1 row)
Note that GaussDB(DWS) may implicitly convert data types. Therefore, you are advised to specify the parameter type when invoking an overloaded function.
SELECT java_dummy(5::varchar); java_dummy ---------------- 5 (1 row)
In this case, the specified parameter type is preferentially used for matching. If there is no Java method matching the specified parameter type, the system implicitly converts the parameter and searches for Java methods based on the conversion result.
SELECT java_dummy(5::INTEGER); java_dummy ----------------- 10 (1 row) DROP FUNCTION java_dummy(INTEGER); SELECT java_dummy(5::INTEGER); java_dummy ---------------- 5 (1 row)
NOTICE:
Data types supporting implicit conversion are as follows:
- SMALLINT: It can be converted to the INTEGER type by default.
- SMALLINT and INTEGER: They can be converted to the BIGINT type by default.
- TINYINT, SMALLINT, INTEGER, and BIGINT: They can be converted to the BOOL type by default.
- The following data types can be converted to TEXT by default: CHAR, NAME, BIGINT, INTEGER, SMALLINT, TINYINT, RAW, FLOAT4, FLOAT8, BPCHAR, VARCHAR, NVARCHAR2, DATE, TIMESTAMP, TIMESTAMPTZ, NUMERIC, and SMALLDATETIME.
- The following data types can be converted to VARCHAR by default: TEXT, CHAR, BIGINT, INTEGER, SMALLINT, TINYINT, RAW, FLOAT4, FLOAT8, BPCHAR, DATE, NVARCHAR2, TIMESTAMP, NUMERIC, and SMALLDATETIME.
- Delete the overloaded functions.
To delete an overloaded function, specify the parameter type for the function. Otherwise, the function cannot be deleted.
DROP FUNCTION java_dummy(INTEGER);
GUC Parameters
- udf_memory_limit
A system-level GUC parameter. It is used to limit the physical memory used by each CN or DN for executing UDFs. The default value is 0.05 * max_process_memory. You can use the postgresql.conf file to modify the parameter setting. The modification takes effect only after the database is restarted.
NOTICE:
- udf_memory_limit is a part of max_process_memory. When a CN or DN is started, memory calculated by udf_memory_limit minus 200 MB will be reserved for Worker processes. CN and DN processes are different from the UDF Worker process, and the CN and DN processes will save memory for the UDF Worker process.
For example, if max_process_memory is set to 10GB on a DN and udf_memory_limit is set to 4GB, the DN can use a maximum of 6.2 GB memory, that is, 10 GB – (4 GB – 200 MB). This case applies even if no UDF is executed. By default, the value of udf_memory_limit is 0.05 * max_process_memory. Querying the pv_total_memory_detail view will prove that the value of process_used_memory would never exceed the calculation result of max_process_memory – (udf_memory_limit – 200MB).
- Executing a simplest Java UDF on a CN consumes about 50 MB physical memory. You can set this parameter based on the memory usage and concurrency of Java functions to be used. After this parameter is added, you are not advised to set UDFWorkerMemHardLimit and FencedUDFMemoryLimit.
- If the parallelism of the UDF process is excessively high and the memory usage exceeds the udf_memory_limit value, unexpected situations such as process exit may occur. In this scenario, the execution result may be unreliable. You are advised to set this parameter to reserve sufficient memory based on the site requirements. If the system has the /var/log/messages log, check the log to see whether the memory is insufficient because the cgroup memory limit has been reached. If the memory is severely insufficient, the UDF master process may exit. You can view the UDF log for analysis. The default UDF log path is $GAUSSLOG/cm/cm_agent/pg_log. For example, if the following log is displayed, the memory resources are insufficient and the UDF master process exits. In this case, you need to check the udf_memory_limit parameter.
0 [BACKEND] FATAL: poll() failed: Bad address, please check the parameter:udf_memory_limit to make sure there is enough memory.
- udf_memory_limit is a part of max_process_memory. When a CN or DN is started, memory calculated by udf_memory_limit minus 200 MB will be reserved for Worker processes. CN and DN processes are different from the UDF Worker process, and the CN and DN processes will save memory for the UDF Worker process.
- FencedUDFMemoryLimit
A session-level GUC parameter. It is used to specify the maximum virtual memory used by a single Fenced UDF Worker process initiated by a session.
SET FencedUDFMemoryLimit='512MB';
The value range of this parameter is (150 MB, 1G). If the value is greater than 1G, an error will be reported immediately. If the value is less than or equal to 150 MB, an error will be reported during function invoking.
NOTICE:
- If FencedUDFMemoryLimit is set to 0, the virtual memory for a Fenced UDF Worker process will not be limited.
- You are advised to use udf_memory_limit to control the physical memory used by Fenced UDF Worker processes. You are not advised to use FencedUDFMemoryLimit, especially when Java UDFs are used. If you are clear about the impact of this parameter, set it based on the following information:
- After a C Fenced UDF Worker process is started, it will occupy about 200 MB virtual memory, and about 16 MB physical memory.
- After a Java Fenced UDF Worker process is started, it will occupy about 2.5 GB virtual memory, and about 50 MB physical memory.
Exception Handling
If there is an exception in a JVM, PL/Java will export JVM stack information during the exception to a client.
Logging
PL/Java uses the standard Java Logger. Therefore, you can record logs as follows:
Logger.getAnonymousLogger().config( "Time is " + new Date(System.currentTimeMillis()));
An initialized Java Logger class is set to the CONFIG level by default, corresponding to the LOG level in GaussDB(DWS). In this case, log messages generated by Java Logger are all redirected to the GaussDB(DWS) backend. Then, the log messages are written into server logs or displayed on the user interface. MPPDB server logs record information at the LOG, WARNING, and ERROR levels. The SQL user interface displays logs at the WARNING and ERROR levels. The following table lists mapping between Java Logger levels and GaussDB(DWS) log levels.
java.util.logging.Level |
GaussDB(DWS) Log Level |
---|---|
SERVER |
ERROR |
WARNING |
WARNING |
CONFIG |
LOG |
INFO |
INFO |
FINE |
DEBUG1 |
FINER |
DEBUG2 |
FINEST |
DEBUG3 |
You can change Java Logger levels. For example, if the Java Logger level is changed to SEVERE by the following Java code, log messages (msg) will not be recorded in GaussDB(DWS) logs during WARNING logging.
Logger log = Logger.getAnonymousLogger(); Log.setLevel(Level.SEVERE); log.log(Level.WARNING, msg);
Security Issues
In GaussDB(DWS), PL/Java is an untrusted language. Only user sysadmin can create PL/Java functions. The user can grant other users the permission for using the PL/Java functions. For details, see Authorize permissions for functions.
In addition, PL/Java controls user access to file systems, forbidding users from reading most system files, or writing, deleting, or executing any system files in Java methods.
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