MySQL: Optimizing JOINs to find non-matching records - mysql

Question

We have a host management system (let's call it CMDB), and a DNS system, each using different tables. The former syncs to the latter, but manual changes cause them to get out of sync. I would like to craft a query to find aliases in CMDB that do NOT have a matching entry in DNS (either no entry, or the name/IP is different)
Because of the large size of the tables, and the need for this query to run frequently, optimizing the query is very important.
Here's what the tables look like:
cmdb_record: id, ipaddr
cmdb_alias: record_id, host_alias
dns_entry: name, ipaddr
cmdb_alias.record_id is a foreign key from cmdb_record.id, so that one IP address can have multiple aliases.
So far, here's what I've come up with:
SELECT cmdb_alias.host_alias, cmdb_record.ipaddr
FROM cmdb_record
INNER JOIN cmdb_alias ON cmdb_alias.record_id = cmdb_record.id
LEFT JOIN dns_entry
ON dns_entry.ipaddr = cmdb_record.ipaddr
AND dns_entry.name = cmdb_alias.host_alias
WHERE dns_entry.ipaddr IS NULL OR dns_entry.name IS NULL
This seems to work, but takes a very long time to run. Is there a better way to do this? Thanks!
EDIT: As requested, here are the SHOW CREATE TABLEs. There are lots of extra fields that aren't particularly relevant, but included for completeness.
Create Table: CREATE TABLE `cmdb_record` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`ip_version` int(11) DEFAULT NULL,
`ipaddr` varchar(40) DEFAULT NULL,
`ipaddr_numeric` decimal(40,0) DEFAULT NULL,
`block_id` int(11) NOT NULL,
`record_commented` tinyint(1) NOT NULL,
`mod_time` datetime NOT NULL,
`deleted` tinyint(1) NOT NULL,
`deleted_date` datetime DEFAULT NULL,
`record_owner` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ipaddr` (`ipaddr`),
KEY `cmdb_record_fe30f0f7` (`ipaddr`),
KEY `cmdb_record_2b8b575` (`ipaddr_numeric`),
KEY `cmdb_record_45897ef2` (`block_id`),
CONSTRAINT `block_id_refs_id_ed6ed320` FOREIGN KEY (`block_id`) REFERENCES `cmdb_block` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=104427 DEFAULT CHARSET=latin1
Create Table: CREATE TABLE `cmdb_alias` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`host_alias` varchar(255) COLLATE latin1_general_cs NOT NULL,
`record_id` int(11) NOT NULL,
`record_order` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `cmdb_alias_fcffc3bb` (`record_id`),
KEY `alias_lookup` (`host_alias`),
CONSTRAINT `record_id_refs_id_8169fc71` FOREIGN KEY (`record_id`) REFERENCES `cmdb_record` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=155433 DEFAULT CHARSET=latin1 COLLATE=latin1_general_cs
Create Table: CREATE TABLE `dns_entry` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`rec_grp_id` varchar(40) NOT NULL,
`parent_id` int(11) NOT NULL,
`domain_id` int(11) DEFAULT NULL,
`name` varchar(255) DEFAULT NULL,
`type` varchar(6) DEFAULT NULL,
`ipaddr` varchar(255) DEFAULT NULL,
`ttl` int(11) DEFAULT NULL,
`prio` int(11) DEFAULT NULL,
`status` varchar(20) NOT NULL,
`op` varchar(20) NOT NULL,
`mod_time` datetime NOT NULL,
`whodunit` varchar(50) NOT NULL,
`comments` longtext NOT NULL,
PRIMARY KEY (`id`),
KEY `dns_entry_a2431ea` (`domain_id`),
KEY `dns_entry_52094d6e` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=49437 DEFAULT CHARSET=utf8

Answer 1

If you don't have one already, create an index on dns_entry(ipaddr, name). This might be all you need to speed the query.