mysql - 如何在 MySQL 中使用 LEFT JOIN 优化 SELECT INTO OUTFILE 查询

Question

我正在一个有 445 万行的表上运行以下查询，该查询需要超过 15-20 分钟才能完成操作。我也尝试将引擎从 Innodb 更改为 MyISAM，但没有任何效果。我还尝试添加类型为普通和唯​​一的多个索引，但仍然需要相同的时间。

这是我的查询:

SELECT 
a.source, a.destination, a.forward_to, a.start_epoch, a.end_epoch, a.duration, a.billsec, a.outbound_billsec, a.pool_id, a.group_id, a.cost, a.outbound_cost, a.net, a.keep, a.payin, a.payout, a.campaign_id, a.buyer, a.hangup_cause, a.endpoint_disposition, a.uuid, a.agreement, a.agreement_type, a.contract, a.contract_type, a.sip_received_ip,a.termination_ip, 
REPLACE(REPLACE(ifnull(b.line_type,''),'\n',' '),'\r',' ') AS line_type, 
REPLACE(REPLACE(ifnull(b.ocn,''),'\n',' '),'\r',' ') AS ocn, 
REPLACE(REPLACE(ifnull(b.spid_carrier_name,''),'\n',' '),'\r',' ') AS spid_carrier_name 
INTO OUTFILE '/tmp/test-husnain01' 
FIELDS TERMINATED BY ',' FROM inbound_022018 a 
LEFT JOIN wireless_checks b ON (a.uuid = b.uuid) 
WHERE date(a.start_epoch)='2018-02-19' AND 
a.endpoint_disposition='ANSWER' AND 
a.direction='inbound' AND 
a.billed=1;

下面是我的表结构(inbound_022018):

      CREATE TABLE `inbound_022018` (
        `id` int(11) NOT NULL AUTO_INCREMENT,
        `source` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `destination` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `prefix` int(22) NOT NULL,
        `forward_to` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `supplier` varchar(32) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `agreement` int(11) NOT NULL,
        `agreement_type` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `payout` float(11,4) NOT NULL,
        `pool_id` int(11) NOT NULL,
        `group_id` int(11) NOT NULL,
        `campaign_id` bigint(22) NOT NULL,
        `lead` int(1) NOT NULL,
        `cpl` float(11,4) NOT NULL,
        `buyer` varchar(32) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `contract` int(11) NOT NULL,
        `contract_type` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `payin` float(11,4) NOT NULL,
        `gross` float(11,4) NOT NULL,
        `cost` float(11,4) NOT NULL,
        `outbound_cost` float(11,4) NOT NULL,
        `net` float(11,4) NOT NULL,
        `keep` float(11,4) NOT NULL,
        `direction` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `session_id` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `uuid` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `sip_from_uri` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `sip_received_ip` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `domain_name` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `sip_req_uri` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `endpoint_disposition` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `hangup_cause` varchar(80) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `hangup_cause_q850` varchar(80) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
        `start_epoch` datetime DEFAULT NULL,
        `answer_epoch` datetime DEFAULT NULL,
        `bridge_epoch` datetime DEFAULT NULL,
        `progress_epoch` datetime DEFAULT NULL,
        `progress_media_epoch` datetime NOT NULL,
        `end_epoch` datetime NOT NULL,
        `digits_dialed` varchar(10) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `last_app` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `last_arg` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `duration` int(11) NOT NULL,
        `g30` int(1) DEFAULT NULL,
        `billsec` int(11) NOT NULL,
        `outbound_duration` int(11) NOT NULL,
        `outbound_billsec` int(11) NOT NULL,
        `progresssec` int(11) NOT NULL,
        `answersec` int(11) NOT NULL,
        `waitsec` int(11) NOT NULL,
        `progress_mediasec` int(11) NOT NULL,
        `flow_billsec` int(11) NOT NULL,
        `sip_hangup_disposition` int(11) NOT NULL,
        `callForwarded` varchar(10) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `forwardUuid` varchar(40) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `call_type` enum('s','v') CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL DEFAULT 's',
        `billed` int(1) NOT NULL,
        `uc` int(1) NOT NULL,
        `suc` int(1) NOT NULL,
        `callinfo` varchar(250) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `termination_ip` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `switchname` varchar(10) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
        `org_charges` float(11,4) NOT NULL,
        `call_summary` text,
        PRIMARY KEY (`id`),
        UNIQUE KEY `index_inbound_0717` (`id`) USING BTREE,
        UNIQUE KEY `index_uuid` (`uuid`) USING BTREE,
        UNIQUE KEY `index_all` (`id`,`campaign_id`,`session_id`,`uuid`) USING BTREE,
        KEY `index_source` (`source`) USING BTREE,
        KEY `index_destination` (`destination`) USING BTREE,
        KEY `index_endpoint` (`endpoint_disposition`) USING BTREE,
        KEY `index_build` (`billed`) USING BTREE,
        KEY `index_campainid` (`campaign_id`) USING BTREE
      ) ENGINE=MyISAM AUTO_INCREMENT=4457485 DEFAULT CHARSET=latin1

这是第二个表(wireless_checks):

         CREATE TABLE `wireless_checks` (
        `id` int(22) NOT NULL AUTO_INCREMENT,
        `date` varchar(10) NOT NULL,
        `uuid` varchar(100) NOT NULL,
        `tn` varchar(11) NOT NULL,
        `lrn` varchar(11) NOT NULL,
        `ported_status` varchar(2) NOT NULL,
        `ported_date` varchar(11) NOT NULL,
        `ocn` varchar(10) NOT NULL,
        `line_type` int(1) NOT NULL,
        `spid` varchar(10) NOT NULL,
        `spid_carrier_name` varchar(100) NOT NULL,
        `spid_carrier_type` varchar(10) NOT NULL,
        `altspid_carrier_name` varchar(10) NOT NULL,
        `altspid_carrier_type` varchar(10) NOT NULL,
        PRIMARY KEY (`id`),
        UNIQUE KEY `index_uuid` (`uuid`) USING BTREE
      ) ENGINE=MyISAM AUTO_INCREMENT=36175 DEFAULT CHARSET=latin1

请指导我如何优化此查询以减少执行时间。如果有任何其他方法可以完成此任务，我也愿意接受解决方法。任何帮助将不胜感激。

谢谢

胡斯奈因

Answer 1

一个应该有所作为的技巧是，而不是这样做

WHERE date(a.start_epoch)='2018-02-19'

您应该考虑预先计算，然后使用实际值，即 1518998400

这是一个危险信号的原因是，通过将一个函数放在比较的左侧，您将强制数据库进行全表扫描，在所有 445 万行上运行该函数，只是为了处理WHERE 子句。相反，如果您将列本身与实际值进行比较，而不使用 DATE 函数，那么 MySQL 可以更有效地优化查询，并将在 a.start_epoch 上使用索引> 如果有的话。

要创建该索引，只需执行

CREATE INDEX epoch_idx on inbound_022018(start_epoch)

更广泛地说，您应该针对具有大量值(而不仅仅是 1 或 2 种可能性)的列创建索引，并且多列索引可以帮助优化复杂查询。

将 EXPLAIN 放在查询前面，并查看特别大的行数的结果，是确定查询中成本所在位置的好方法。通常，有效的索引可以解决问题。