Generic MySQL backend

• Native: Yes
• Master: Yes
• Slave: Yes
• Superslave: Yes
• Case: All lower
• DNSSEC: Yes (set gmysql-dnssec)
• Disabled data: Yes
• Comments: Yes
• Zone caching: Yes
• Module name: gmysql
• Launch name: gmysql

Warning

If using MySQL with ‘slave’ support enabled in PowerDNS you must run MySQL with a table engine that supports transactions. In practice, great results are achieved with the ‘InnoDB’ tables. PowerDNS will silently function with non-transaction aware MySQLs but at one point this is going to harm your database, for example when an incoming zone transfer fails.

Warning

While it is possible to run the Generic MySQL backend on top of MySQL views, we have received several reports of this causing performance problems and memory leaks. Please know that when reporting problems when running PowerDNS on top of a modified schema, our open source support offering requires you to reproduce your problem on an unmodified schema without views.

The default schema is included at the bottom of this page. Using zone2sql with the --gmysql flag also assumes this layout is in place. For full migration notes, please see Migrating to PowerDNS. This schema contains all elements needed for master, slave and superslave operation.

When using the InnoDB storage engine, we suggest adding foreign key constraints to the tables in order to automate deletion of records, key material, and other information upon deletion of a domain from the domains table. The following SQL does the job:

/*
Using this SQL causes Mysql to create foreign keys on your database. This will
make sure that no records, comments or keys exists for domains that you already
removed. This is not enabled by default, because we're not sure what the
consequences are from a performance point of view. If you do have feedback,
please let us know how this affects your setup.

Please note that it's not possible to apply this, before you cleaned up your
database, as the foreign keys do not exist.
*/
ALTER TABLE records ADD CONSTRAINT `records_domain_id_ibfk` FOREIGN KEY (`domain_id`) REFERENCES `domains` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;
ALTER TABLE comments ADD CONSTRAINT `comments_domain_id_ibfk` FOREIGN KEY (`domain_id`) REFERENCES `domains` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;
ALTER TABLE domainmetadata ADD CONSTRAINT `domainmetadata_domain_id_ibfk` FOREIGN KEY (`domain_id`) REFERENCES `domains` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;
ALTER TABLE cryptokeys ADD CONSTRAINT `cryptokeys_domain_id_ibfk` FOREIGN KEY (`domain_id`) REFERENCES `domains` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;

Using MySQL replication

To support NATIVE domains, the binlog_format for the MySQL replication must be set to MIXED or ROW to prevent differences in data between replicated servers. See “Setting The Binary Log Format” for more information.

Otherwise, you will probably see:

Cannot execute statement: impossible to write to binary log since BINLOG_FORMAT = STATEMENT and at least one table uses a storage engine limited to row-based logging.
InnoDB is limited to row-logging when transaction isolation level is READ COMMITTED or READ UNCOMMITTED.

Settings

gmysql-host

Host (ip address) to connect to. Mutually exclusive with gmysql-socket.

Warning

When specified as a hostname a chicken/egg situation might arise where the database is needed to resolve the IP address of the database. It is best to supply an IP address of the database here.

gmysql-port

The port to connect to on gmysql-host. Default: 3306.

gmysql-socket

Connect to the UNIX socket at this path. Mutually exclusive with gmysql-host.

gmysql-dbname

Name of the database to connect to. Default: “powerdns”.

gmysql-user

User to connect as. Default: “powerdns”.

gmysql-group

Group to connect as. Default: “client”.

gmysql-password

The password to for gmysql-user.

gmysql-dnssec

Enable DNSSEC processing for this backend. Default: no.

gmysql-innodb-read-committed

Use the InnoDB READ-COMMITTED transaction isolation level. Default: yes.

gmysql-ssl

Deprecated since version 5.0.0.

Before 5.0.0: Send the CLIENT_SSL capability flag to the server. SSL support is announced by the server via CLIENT_SSL and is enabled if the client returns the same capability. Default: no.

5.0.0 and up: this option does nothing. Use gmysql-group and put your TLS settings in my.cnf.

gmysql-timeout

The timeout in seconds for each attempt to read from, or write to the server. A value of 0 will disable the timeout. Default: 10

gmysql-thread-cleanup

Older versions (such as those shipped on RHEL 7) of the MySQL/MariaDB client libraries leak memory unless applications explicitly report the end of each thread to the library. Enabling gmysql-thread-cleanup tells PowerDNS to call mysql_thread_end() whenever a thread ends.

Only enable this if you are certain you need to. For more discussion, see https://github.com/PowerDNS/pdns/issues/6231.

Default Schema

This is the 4.7 schema.

CREATE TABLE domains (
  id                    INT AUTO_INCREMENT,
  name                  VARCHAR(255) NOT NULL,
  master                VARCHAR(128) DEFAULT NULL,
  last_check            INT DEFAULT NULL,
  type                  VARCHAR(8) NOT NULL,
  notified_serial       INT UNSIGNED DEFAULT NULL,
  account               VARCHAR(40) CHARACTER SET 'utf8' DEFAULT NULL,
  options               VARCHAR(64000) DEFAULT NULL,
  catalog               VARCHAR(255) DEFAULT NULL,
  PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE UNIQUE INDEX name_index ON domains(name);
CREATE INDEX catalog_idx ON domains(catalog);


CREATE TABLE records (
  id                    BIGINT AUTO_INCREMENT,
  domain_id             INT DEFAULT NULL,
  name                  VARCHAR(255) DEFAULT NULL,
  type                  VARCHAR(10) DEFAULT NULL,
  content               VARCHAR(64000) DEFAULT NULL,
  ttl                   INT DEFAULT NULL,
  prio                  INT DEFAULT NULL,
  disabled              TINYINT(1) DEFAULT 0,
  ordername             VARCHAR(255) BINARY DEFAULT NULL,
  auth                  TINYINT(1) DEFAULT 1,
  PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX nametype_index ON records(name,type);
CREATE INDEX domain_id ON records(domain_id);
CREATE INDEX ordername ON records (ordername);


CREATE TABLE supermasters (
  ip                    VARCHAR(64) NOT NULL,
  nameserver            VARCHAR(255) NOT NULL,
  account               VARCHAR(40) CHARACTER SET 'utf8' NOT NULL,
  PRIMARY KEY (ip, nameserver)
) Engine=InnoDB CHARACTER SET 'latin1';


CREATE TABLE comments (
  id                    INT AUTO_INCREMENT,
  domain_id             INT NOT NULL,
  name                  VARCHAR(255) NOT NULL,
  type                  VARCHAR(10) NOT NULL,
  modified_at           INT NOT NULL,
  account               VARCHAR(40) CHARACTER SET 'utf8' DEFAULT NULL,
  comment               TEXT CHARACTER SET 'utf8' NOT NULL,
  PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX comments_name_type_idx ON comments (name, type);
CREATE INDEX comments_order_idx ON comments (domain_id, modified_at);


CREATE TABLE domainmetadata (
  id                    INT AUTO_INCREMENT,
  domain_id             INT NOT NULL,
  kind                  VARCHAR(32),
  content               TEXT,
  PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX domainmetadata_idx ON domainmetadata (domain_id, kind);


CREATE TABLE cryptokeys (
  id                    INT AUTO_INCREMENT,
  domain_id             INT NOT NULL,
  flags                 INT NOT NULL,
  active                BOOL,
  published             BOOL DEFAULT 1,
  content               TEXT,
  PRIMARY KEY(id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE INDEX domainidindex ON cryptokeys(domain_id);


CREATE TABLE tsigkeys (
  id                    INT AUTO_INCREMENT,
  name                  VARCHAR(255),
  algorithm             VARCHAR(50),
  secret                VARCHAR(255),
  PRIMARY KEY (id)
) Engine=InnoDB CHARACTER SET 'latin1';

CREATE UNIQUE INDEX namealgoindex ON tsigkeys(name, algorithm);