Migration and Upgrade

This guide provides detailed instructions for two scenarios:

1. Migrating from Greenplum Database 6.x/7.x to Apache Cloudberry
2. Upgrading from Apache Cloudberry 1.x (non-Apache release before joining the Apache Incubator) to Apache Cloudberry 2.x

Both scenarios utilize the cbcopy tool, a powerful data migration utility designed for efficient database migration and upgrade operations.

Prerequisites

Before starting the migration or upgrade process, ensure you have:

1. Go Programming language version 1.19 or higher installed
2. Superuser privileges on both source and target databases
3. Network connectivity between source and target database clusters
4. Sufficient disk space on both source and target clusters
5. The cbcopy and cbcopy_helper binaries installed in the $GPHOME/bin directory on all nodes of both source and target databases

Installing cbcopy

1. Clone the repository:

git clone https://github.com/cloudberry-contrib/cbcopy.git

2. Build the binaries:

cd cbcopy
make

3. Install the binaries:

make install

Version Compatibility

Cloudberry Upgrade (1.x to 2.x)

• Source: Cloudberry 1.6
• Target: Cloudberry 2.0

Greenplum to Cloudberry Migration

• Source: Greenplum Database 6.x or 7.x
• Target: Cloudberry 1.x or 2.x

Migration Process

The migration process consists of two main phases:

1. Metadata migration
2. Data migration

We recommend performing these phases separately for better control and reliability:

1. First migrate metadata using --metadata-only
2. Then migrate data using --data-only

Basic Migration Command

cbcopy --source-host=<source_host> \
    --source-port=<source_port> \
    --source-user=<source_user> \
    --dest-host=<dest_host> \
    --dest-port=<dest_port> \
    --dest-user=<dest_user> \
    [additional_options]

Migration Modes

cbcopy supports several migration modes:

1. Full Migration (--full)

   • Migrates all metadata and data from source to target

2. Database Migration (--dbname)

   • Migrates specific database(s)

   cbcopy --dbname="database1,database2" [other_options]

3. Schema Migration (--schema)

   • Migrates specific schema(s)

   cbcopy --schema="database.schema1,database.schema2" [other_options]

4. Table Migration (--include-table)

   • Migrates specific table(s)

   cbcopy --include-table="database.schema.table1,database.schema.table2" [other_options]

Data Loading Options

1. Append Mode (--append)

   • Inserts migrated records into existing tables
   • Use when you want to preserve existing data

2. Truncate Mode (--truncate)

   • Clears existing records before inserting migrated data
   • Use when you want to replace existing data

   cbcopy --truncate [other_options]

Handling Dependencies

Global Objects

For tables depending on global objects (e.g., tablespaces):

1. Use --with-global-metadata to automatically create these objects
2. Or manually create them before migration:

   CREATE TABLESPACE custom_tablespace LOCATION '/path/to/tablespace';

Role Management

To change table ownership during migration:

1. Create target roles in the target database
2. Use --owner-mapping-file to specify role mappings:

   source_role1,target_role1
   source_role2,target_role2

Tablespace Management

Three options for handling tablespaces:

1. Default Mode

   • Objects created in same tablespace names as source
   • Use --with-global-metadata or manually create tablespaces

2. Single Target Tablespace (--dest-tablespace)

   cbcopy --dest-tablespace=new_space [other_options]

3. Tablespace Mapping (--tablespace-mapping-file)

   source_tablespace1,target_tablespace1
   source_tablespace2,target_tablespace2

Performance Optimization

1. Parallel Jobs

   • Control concurrent table copies with --copy-jobs

   cbcopy --copy-jobs=8 [other_options]

2. Copy Strategies cbcopy automatically selects the optimal strategy based on table size:

   • Copy On Coordinator: For small tables
   • Copy On Segment: For large tables with matching cluster configurations
   • Copy on External Table: For other cases

Migration Validation

cbcopy performs automatic validation by comparing row counts between source and target. Failed migrations are logged in:

• $USER/gpAdminLogs/cbcopy_succeed_$timestamp
• $USER/gpAdminLogs/cbcopy_failed_$timestamp

For retry attempts, use:

cbcopy --exclude-table-file=cbcopy_succeed_$timestamp [other_options]

Example Scenarios

Scenario 1: Cloudberry 1.6 to 2.0 Upgrade

# Step 1: Migrate metadata
cbcopy --source-host=127.0.0.1 \
    --source-port=15432 \
    --source-user=gpadmin \
    --dest-host=127.0.0.1 \
    --dest-port=25432 \
    --dest-user=gpadmin \
    --full \
    --metadata-only

# Step 2: Migrate data
cbcopy --source-host=127.0.0.1 \
    --source-port=15432 \
    --source-user=gpadmin \
    --dest-host=127.0.0.1 \
    --dest-port=25432 \
    --dest-user=gpadmin \
    --full \
    --data-only \
    --truncate

Scenario 2: Greenplum 6.x/7.x to Cloudberry 2.0 Migration

# Step 1: Migrate metadata with global objects
cbcopy --source-host=127.0.0.1 \
    --source-port=15432 \
    --source-user=gpadmin \
    --dest-host=127.0.0.1 \
    --dest-port=25432 \
    --dest-user=gpadmin \
    --full \
    --metadata-only \
    --with-global-metadata

# Step 2: Migrate data
cbcopy --source-host=127.0.0.1 \
    --source-port=15432 \
    --source-user=gpadmin \
    --dest-host=127.0.0.1 \
    --dest-port=25432 \
    --dest-user=gpadmin \
    --full \
    --data-only \
    --truncate \
    --copy-jobs=8

Troubleshooting

1. Failed Migrations

   • Check $USER/gpAdminLogs/cbcopy_$timestamp.log for detailed error messages
   • Use the success/failure files to retry failed migrations

2. Common Issues

   • Ensure all required tablespaces exist in target database
   • Verify network connectivity between source and target
   • Check user permissions on both databases
   • Ensure sufficient disk space on both clusters

Additional Resources

• cbcopy GitHub Repository

备注

cbcopy is contributed by community members; however, please note that it is not maintained as an official Cloudberry project yet.