openHalo

OpenHalo is an open-source PostgreSQL kernel that provides MySQL wire-protocol compatibility.

openHalo is based on PostgreSQL 14.18 and provides wire-level compatibility with MySQL 5.7.32-log / 8.0. Pigsty delivers it through pg_mode: mysql and the openhalo package alias.

Pigsty supports OpenHalo deployment on all supported Linux platforms.

• RPM build spec: github.com/pgsty/rpm/rpmbuild/specs/openhalodb.spec
• DEB build spec: github.com/pgsty/deb/debbuild/openhalodb

Quick Start

Use Pigsty’s standard installation flow with the mysql template.

curl -fsSL https://repo.pigsty.io/get | bash; cd ~/pigsty;
./configure -c mysql    # Use MySQL (openHalo) template
./deploy.yml            # Install (change passwords in pigsty.yml before production use)

Cluster Config

pg-meta:
  hosts:
    10.10.10.10: { pg_seq: 1, pg_role: primary }
  vars:
    pg_cluster: pg-meta
    pg_users:
      - {name: dbuser_meta ,password: DBUser.Meta   ,pgbouncer: true ,roles: [dbrole_admin]    ,comment: pigsty admin user }
      - {name: dbuser_view ,password: DBUser.Viewer ,pgbouncer: true ,roles: [dbrole_readonly] ,comment: read-only viewer for meta database }
    pg_databases:
      - {name: postgres, extensions: [ aux_mysql ]} # mysql-compatible database
      - {name: meta ,baseline: cmdb.sql ,comment: pigsty meta database ,schemas: [pigsty]}
    pg_hba_rules:
      - {user: dbuser_view , db: all ,addr: infra ,auth: pwd ,title: 'allow grafana dashboard access cmdb from infra nodes'}
    pg_crontab: [ '00 01 * * * /pg/bin/pg-backup full' ] # full backup at 1 AM daily

    # OpenHalo specific settings
    pg_mode: mysql
    pg_version: 14
    pg_packages: [ openhalo, pgsql-common ]

The OpenHalo extension aux_mysql provides functions and types for MySQL compatibility. Enable it in the postgres database for full compatibility behavior.

• aux_mysql 1.5: MySQL Supplementary Extension
• /usr/halo-14/share/postgresql/extension/aux_mysql.control
• $libdir/mysm, mysm.so

Usage

MySQL connections use the postgres database. A MySQL database maps to a PostgreSQL schema. Thus, use mysql selects the mysql schema in the postgres database.

Use the PostgreSQL usernames and passwords for MySQL access.

Client Access

OpenHalo listens on port 3306 for MySQL wire protocol clients.

Pigsty’s conf/mysql installs a MySQL client by default.

mysql -h 127.0.0.1 -u dbuser_dba

OpenHalo upstream currently reports that Navicat works normally on this port. IntelliJ DataGrip may fail.

Compatibility Parameters

Pigsty sets database_compat_mode to mysql by default. To adjust compatibility behavior, use settings such as:

mysql.listener_on = true                        # enable MySQL listener; restart required
mysql.port = 3306                               # second_port for MySQL mode; restart required
mysql.halo_mysql_version = '5.7.32-log'         # restart required
mysql.ci_collation = true                       # restart required
mysql.explicit_defaults_for_timestamp = false   # restart required
mysql.auto_rollback_tx_on_error = false         # restart required

Patch Notes

Pigsty packages the OpenHalo kernel from HaloTech-Co-Ltd/openHalo with these adjustments:

• Restore default database name from halo0root to postgres
• Remove 1.0. prefix in the default version string, keeping 14.18
• Adjust default config to enable MySQL compatibility and listen on 3306

Pigsty does not provide warranty coverage for OpenHalo kernel behavior. Contact the upstream vendor about kernel-specific issues.

Warning: This kernel is currently in beta1. Evaluate its risks carefully before production use.

Available Extensions

The OpenHalo kernel has 59 available extensions. The following table lists the extra extensions, excluding bundled PG Contrib extensions: