MySQL - Optimise Query - mysql

Question

I have been left with a report which returns rows at an awfully slow rate. I feel I need to redo without so many or any sub-queries. But I am having a complete brain freeze to how to attempt this.
I have looked at indexes and the keys are not unique enough, which forces a full table scan time. Is there any way I can pull certain information from the other tables using a separate query, adding that as a variable and use it in the main query. As really the result of this query is only a few lines.
Are there any tips or tricks, that I could use to optimise or correct this SQL statement to speed it up.
(EDIT) I have added some create code for the tables.
SELECT
case when (select count(ag.`PKEY`) - count(ag.`ANSWERTIME`) from acdcallinformation ag
where (ag.`COMPLETED`) = 1 and answertime is null and time(ag.INSTIME) and DATE_FORMAT(DATEOFCALL,'%Y-%m-%d') >= date(now()) and ag.skillid = acdcallinformation.skillid) is null
then 0
else
(select count(ag.`PKEY`) - count(ag.`ANSWERTIME`) from acdcallinformation ag where (ag.`COMPLETED`) = 1
and answertime is null and DATE_FORMAT(DATEOFCALL,'%Y-%m-%d') >= date(now()) and ag.skillid = acdcallinformation.skillid)
end as LostCalls,
case when count(acdcallinformation.idleonqueue) is null then 0 else count(acdcallinformation.idleonqueue) end as CountCallsACD,
case when count(acdcallinformation.`ANSWERTIME`) is null then 0 else count(acdcallinformation.`ANSWERTIME`) end AS acdcallinformation_ANSWERED,
(select skillinfo.skillname from skillinfo where skillinfo.pkey = acdcallinformation.skillid) AS acdcallinformation_SKILLIDTEXT,
(select count(pkey) from acdcallinformation age
where DATE_FORMAT(DATEOFCALL,'%Y-%m-%d') >= date(now()) and age.skillid = acdcallinformation.skillid and (age.`COMPLETED`) = 0 and answertime is null
and SKILLID in (select SKILLID
from
callcenterinformation
where time > (now() - INTERVAL 5 SECOND) and callswaiting > 0)) as Waiting,
-- count(acdcallinformation.`PKEY`) as CallsWaiting,
acdcallinformation.`DATEOFCALL` AS acdcallinformation_DATEOFCALL,
acdcallinformation.`FIRSTRINGONQUEUE` AS acdcallinformation_FIRSTRINGONQUEUE,
case when acdcallinformation.`CONNECTTIME` is null then time('00:00:00') else acdcallinformation.`CONNECTTIME` end AS acdcallinformation_CONNECTTIME,
acdcallinformation.`CALLSTATEBEFOREIDLE` AS acdcallinformation_CALLSTATEBEFOREIDLE,
case when acdcallinformation.`AGENTRINGTIME` is null then time('00:00:00') else acdcallinformation.`AGENTRINGTIME` end AS acdcallinformation_AGENTRINGTIME,
acdcallinformation.`IDLEONQUEUE` AS acdcallinformation_IDLEONQUEUE,
acdcallinformation.`DDI` AS acdcallinformation_DDI,
acdcallinformation.`CLIP` AS acdcallinformation_CLIP,
acdcallinformation.`SKILLID` AS acdcallinformation_SKILLID,
acdcallinformation.`ACTIONTYPE` AS acdcallinformation_ACTIONTYPE,
acdcallinformation.`ACTIONDESTINATION` AS acdcallinformation_ACTIONDESTINATION,
acdcallinformation.`COMPLETED` AS acdcallinformation_COMPLETED,
acdcallinformation.`HANDLED` AS acdcallinformation_HANDLED,
acdcallinformation.`CONFIRMED` AS acdcallinformation_CONFIRMED,
(
SELECT
cal.`AGENTSREADY` AS callcenterinformation_AGENTSREADY
FROM
`callcenterinformation` cal
WHERE cal.skillid <> 1 and acdcallinformation.skillid = skillid order by pkey desc limit 1,1) as agentsready
FROM
`acdcallinformation` acdcallinformation
where DATE_FORMAT(DATEOFCALL,'%Y-%m-%d') >= date(now()- interval 1 day )
group by (select skillinfo.skillname from skillinfo where skillinfo.pkey = acdcallinformation.skillid);
CREATE TABLE `callcenterinformation` (
`INSTIME` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
`PKEY` INT(11) NOT NULL,
`SKILLID` INT(11) NULL DEFAULT '0',
`DATE` DATE NULL DEFAULT NULL,
`TIME` TIME NULL DEFAULT NULL,
`AGENTSLOGGEDIN` INT(11) NULL DEFAULT '0',
`AGENTSREADY` INT(11) NULL DEFAULT '0',
`AGENTSRINGING` INT(11) NULL DEFAULT '0',
`AGENTSCONNECTED` INT(11) NULL DEFAULT '0',
`AGENTSINPAUSE` INT(11) NULL DEFAULT '0',
`AGENTSINWRAPUP` INT(11) NULL DEFAULT '0',
`CALLSWAITING` INT(11) NULL DEFAULT '0',
`COMPLETED` TINYINT(1) NULL DEFAULT '0',
`HANDLED` TINYINT(1) NULL DEFAULT '0',
`CONFIRMED` TINYINT(1) NULL DEFAULT '0',
PRIMARY KEY (`PKEY`),
INDEX `DATE` (`DATE`),
INDEX `TIME` (`TIME`),
INDEX `SKILLID` (`SKILLID`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB;
CREATE TABLE `acdcallinformation` (
`INSTIME` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
`PKEY` INT(11) NOT NULL,
`DATEOFCALL` DATE NULL DEFAULT NULL,
`FIRSTRINGONQUEUE` TIME NULL DEFAULT NULL,
`CONNECTTIME` TIME NULL DEFAULT NULL,
`CALLSTATEBEFOREIDLE` INT(11) NULL DEFAULT '0',
`AGENTRINGTIME` TIME NULL DEFAULT NULL,
`ANSWERTIME` TIME NULL DEFAULT NULL,
`IDLEONQUEUE` TIME NULL DEFAULT NULL,
`DDI` TEXT NULL,
`CLIP` TEXT NULL,
`SKILLID` INT(11) NULL DEFAULT '0',
`ACTIONTYPE` INT(11) NULL DEFAULT '0',
`ACTIONDESTINATION` TEXT NULL,
`COMPLETED` TINYINT(1) NULL DEFAULT '0',
`HANDLED` TINYINT(1) NULL DEFAULT '0',
`CONFIRMED` TINYINT(1) NULL DEFAULT '0',
PRIMARY KEY (`PKEY`),
INDEX `DATEOFCALL` (`DATEOFCALL`),
INDEX `IDLEONQUEUE_HANDLED` (`IDLEONQUEUE`, `HANDLED`),
INDEX `SKILLID` (`SKILLID`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB;
CREATE TABLE `skillinfo` (
`INSTIME` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
`PKEY` INT(11) NOT NULL,
`SKILLNAME` TEXT NULL,
`CLIP` TEXT NULL,
`WRAPUPTIMELENGTH` INT(11) NULL DEFAULT '0',
`MAXRINGTIMELENGTH` INT(11) NULL DEFAULT '0',
`FORCEDTICKET` TINYINT(1) NULL DEFAULT '0',
`STATEAFTERWRAPUP` INT(11) NULL DEFAULT '0',
`STATEAFTERUNANSWEREDCALL` INT(11) NULL DEFAULT '0',
`ACTIONTYPE` INT(11) NULL DEFAULT '0',
`ACTIONDESTINATION` TEXT NULL,
`DEFLECTAFTERCOURTESY` TINYINT(1) NULL DEFAULT '0',
`MAXOVERALLRINGTIMELENGTH` INT(11) NULL DEFAULT '0',
`AUTOCLIP` TINYINT(1) NULL DEFAULT '0',
`OUTGOINGSETTINGSACTIVE` TINYINT(1) NULL DEFAULT '0',
`NUMPLANIDENTIFIER` INT(11) NULL DEFAULT '0',
`TYPEOFNUMBER` INT(11) NULL DEFAULT '0',
`CLIR` INT(11) NULL DEFAULT '0',
`OUTGOINGROUTEID` INT(11) NULL DEFAULT '0',
`USELASTAGENT` TINYINT(1) NULL DEFAULT '0',
`CLIPROUTINGACTIVE` TINYINT(1) NULL DEFAULT '0',
`USETHRESHOLD` TINYINT(1) NULL DEFAULT '0',
`NORMALLOADTHRESHOLD` INT(11) NULL DEFAULT '0',
`OVERLOADTHRESHOLD` INT(11) NULL DEFAULT '0',
`STATEAFTERFORWARD` INT(11) NULL DEFAULT '0',
`CALLDISTTYPE` INT(11) NULL DEFAULT '0',
`USERGROUPID` INT(11) NULL DEFAULT '0',
`EXTERNALCONTROL` TINYINT(1) NULL DEFAULT '0',
`LASTAGENTLIMIT` INT(11) NULL DEFAULT '0',
PRIMARY KEY (`PKEY`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB;

Answer 1

Too be honest, there is so much 'wrong' with this query it just isn't fun anymore =/
Some thoughts:
IFNULL() is much more readable than CASE WHEN <field> IS NULL THEN constant ELSE <field> END, especially if turns out to be a sub-query.
AFAIK COUNT(*) will always return 0, even if nothing is found. Thus, there is no need to write an IFNULL() around it
COUNT(field) only counts the non-NULL records for this field, but again, if nothing is found it will return 0, so no need for an IFNULL() around it
You should teach yourself how to JOIN tables as it's (much) better practice than using correlated sub-queries all over the place.
I don't know much about mysql, but it seems to me that you're killing your performance by putting casts and functions around the fields that otherwise seem to have a useful index. I'm pretty sure that due to these constructions the engine simply is not able to use said indexes causing performance to go down the drain. eg. I would try to rewrite
AND DATE_FORMAT(DATEOFCALL,'%Y-%m-%d') >= date(now()) into something like AND DATEOFCALL >= CUR_DATE(), after all, both sides are dates (= numbers)
DATE_FORMAT(DATEOFCALL,'%Y-%m-%d') >= date(now()- interval 1 day) into DATEOFCALL >= date(now()- interval 1 day) for the very same reason
I'm also not sure what time(ag.INSTIME) should do ?!?! Is it true whenever the time is different from 00:00:00 ?
I'm VERY surprised this query actually compiles at all as you seem to GROUP BY on just the skillname, but also fetch quite a lot of other fields from the table (e.g. idleonqueue). From an MSSQL background that should not work.. I guess mysql is different although I do wonder what the result will be like.
Anyway, trying to apply some of the above to your query I end up with below. I doubt it will be 'much faster'; it might be just a bit, but I'd consider it a step forward in your mission to clean it up further...
Good luck!
SELECT (SELECT COUNT(ag.`PKEY`) - COUNT(ag.`ANSWERTIME`)
FROM acdcallinformation ag
WHERE ag.`COMPLETED` = 1
AND answertime is null
AND time(ag.INSTIME)
AND ag.DATEOFCALL >= CURDATE()
AND ag.skillid = info.skillid) AS LostCalls,
COUNT(info.idleonqueue) AS CountCallsACD,
COUNT(info.`ANSWERTIME`) AS acdcallinformation_ANSWERED,
skillinfo.skillname AS acdcallinformation_SKILLIDTEXT,
(SELECT COUNT(pkey)
FROM acdcallinformation age
WHERE age.DATEOFCALL >= CURDATE()
AND age.skillid = info.skillid
AND age.`COMPLETED` = 0
AND age.answertime is null
AND age.SKILLID IN (SELECT SKILLID
FROM callcenterinformation cci
WHERE cci.time > (now() - INTERVAL 5 SECOND)
AND cci.callswaiting > 0)) AS Waiting,
-- count(info.`PKEY`) AS CallsWaiting,
info.`DATEOFCALL` AS acdcallinformation_DATEOFCALL,
info.`FIRSTRINGONQUEUE` AS acdcallinformation_FIRSTRINGONQUEUE,
IFNULL(info.`CONNECTTIME`, time('00:00:00')) AS acdcallinformation_CONNECTTIME,
info.`CALLSTATEBEFOREIDLE` AS acdcallinformation_CALLSTATEBEFOREIDLE,
IFNULL(info.`AGENTRINGTIME`, time('00:00:00')) AS acdcallinformation_AGENTRINGTIME,
info.`IDLEONQUEUE` AS acdcallinformation_IDLEONQUEUE,
info.`DDI` AS acdcallinformation_DDI,
info.`CLIP` AS acdcallinformation_CLIP,
info.`SKILLID` AS acdcallinformation_SKILLID,
info.`ACTIONTYPE` AS acdcallinformation_ACTIONTYPE,
info.`ACTIONDESTINATION` AS acdcallinformation_ACTIONDESTINATION,
info.`COMPLETED` AS acdcallinformation_COMPLETED,
info.`HANDLED` AS acdcallinformation_HANDLED,
info.`CONFIRMED` AS acdcallinformation_CONFIRMED,
(SELECT cal.`AGENTSREADY` AS callcenterinformation_AGENTSREADY
FROM `callcenterinformation` cal
WHERE cal.skillid <> 1
AND cal.skillid = info.skillid
ORDER BY pkey DESC LIMIT 1,1) AS agentsready
FROM `acdcallinformation` info
JOIN `skillinfo`
ON skillinfo.pkey = info.skillid
WHERE info.DATEOFCALL >= (date(now()- interval 1 day ))
GROUP BY skillinfo.skillname ;