[Building Sakai] MSGCNTR Forums mysql picks a slow query plan over a faster query plan
Earle Nietzel
earle.nietzel at gmail.com
Wed Sep 7 13:14:06 PDT 2011
In one of my previous post I mentioned that one of the straight_join queries
chooses the same fast plan when all is working well. I will include it here:
select straight_join count(topicimpl0_.ID) as col_0_0_
from MFR_AREA_T areaimpl3_
inner join MFR_OPEN_FORUM_T openforumi2_ on
openforumi2_.surrogateKey=areaimpl3_.ID
inner join MFR_TOPIC_T topicimpl0_ on
topicimpl0_.of_surrogateKey=openforumi2_.ID
inner join MFR_MEMBERSHIP_ITEM_T membership4_ on
topicimpl0_.ID=membership4_.t_surrogateKey,
MFR_PERMISSION_LEVEL_T permission1_
where areaimpl3_.CONTEXT_ID='
517f8f28-f68e-42ee-b168-919a06f82229'
and topicimpl0_.MODERATED=1
and (membership4_.NAME in ('Student' , 'MATH_111L_114_11F'))
and permission1_.MODERATE_POSTINGS=1
and permission1_.TYPE_UUID!='00000000-0000-0000-7777-000000000000'
and permission1_.NAME=membership4_.PERMISSION_LEVEL_NAME
This query should give the same exact performance as the one without a
straight_join that works well.
Can you give it a try?
On Wed, Sep 7, 2011 at 3:28 PM, Bryan Holladay <holladay at longsight.com>wrote:
> You were right, I grabbed the wrong query... sorry about that... I
> just copied your query in the email and ran explain and this is what I
> got:
>
> with straight_join:
>
> id select_type table type possible_keys key key_len ref
> rows Extra
> 1 SIMPLE topicimpl0_ ALL PRIMARY,FK863DC0BE74C7E92B
> (null) (null) (null) 589086 Using
> where
> 1 SIMPLE openforumi2_ eq_ref PRIMARY,FKC17608478B5E2A2F
> PRIMARY 8 sakai28.topicimpl0_.of_surrogateKey 1
> 1 SIMPLE areaimpl3_ eq_ref
> PRIMARY,MFR_AREA_CONTEXT_UUID_UNIQUE PRIMARY 8
> sakai28.openforumi2_.surrogateKey 1 Using
> where
> 1 SIMPLE membership4_ ref FKE03761CB7DEF8466
> FKE03761CB7DEF8466 9 sakai28.topicimpl0_.ID 6 Using
> where
> 1 SIMPLE permission1_ ref MFR_MODERATE_POSTINGS_IDX
> MFR_MODERATE_POSTINGS_IDX 1 const 15486 Using
> where
>
>
> without straight_join:
>
> id select_type table type possible_keys key key_len ref
> rows Extra
> 1 SIMPLE areaimpl3_ ref
> PRIMARY,MFR_AREA_CONTEXT_UUID_UNIQUE MFR_AREA_CONTEXT_UUID_UNIQUE 767
> const 1 Using
> where; Using index
> 1 SIMPLE openforumi2_ ref PRIMARY,FKC17608478B5E2A2F
> FKC17608478B5E2A2F 9 sakai28.areaimpl3_.ID 1 Using
> where; Using index
> 1 SIMPLE topicimpl0_ ref PRIMARY,FK863DC0BE74C7E92B
> FK863DC0BE74C7E92B 9 sakai28.openforumi2_.ID 37 Using
> where
> 1 SIMPLE membership4_ ref FKE03761CB7DEF8466
> FKE03761CB7DEF8466 9 sakai28.topicimpl0_.ID 6 Using
> where
> 1 SIMPLE permission1_ ref MFR_MODERATE_POSTINGS_IDX
> MFR_MODERATE_POSTINGS_IDX 1 const 15486 Using
> where
>
>
>
> So it still looks like it's faster without straight_join. I've
> attached the csv file for easier reading.
>
>
> On Wed, Sep 7, 2011 at 3:12 PM, Earle Nietzel <earle.nietzel at gmail.com>
> wrote:
> > Thanks for the reply Brian.
> >
> > Everything in your query plan is the same except for the last line:
> >
> > | id | select_type | table | type | possible_keys |
> > key | key_len |
> > ref | rows | Extra
> > | 1 | SIMPLE | permission1_ | ref | MFRPERMLVL_COMPOSITE_IDX1 |
> > MFRPERMLVL_COMPOSITE_IDX1 | 152 |
> > ilearn.membership4_.PERMISSION_LEVEL_NAME | 10410 | Using where
> >
> > Are you looking the right query?
> > Your query looks like
> > "findNumModeratedTopicsForSiteByUserByMembershipWithPermissionLevelId"
> which
> > would make sense since it is using the the PRIMARY key for that last
> line.
> > Look at query
> > "findNumModeratedTopicsForSiteByUserByMembershipWithPermissionLevelName"
> > which uses the permissionLevelName so it can't be the PRIMARY key.
> >
> > Can you check this?
> >
> > Thanks
> > Earle
> >
> > On Wed, Sep 7, 2011 at 2:41 PM, Bryan Holladay <holladay at longsight.com>
> > wrote:
> >>
> >> It still looks like your index's are off... I ran an explain on a huge
> >> db and got better results than the straight_join query. I noticed
> >> your explain is using the PRIMARY index for TOPIC, AREA and OPENFORUM
> >> while my explain only shows PRIMARY for MEMBERSHIP. The results are
> >> pasted below and I've also attached the csv file to make it easier to
> >> read.
> >>
> >> Thanks,
> >> Bryan
> >>
> >> id select_type table type possible_keys key key_len
> >> ref rows Extra
> >> 1 SIMPLE areaimpl3_ ref
> >> PRIMARY,MFR_AREA_CONTEXT_UUID_UNIQUE MFR_AREA_CONTEXT_UUID_UNIQUE
> 767
> >> const 1 Using
> >> where; Using index
> >> 1 SIMPLE openforumi2_ ref PRIMARY,FKC17608478B5E2A2F
> >> FKC17608478B5E2A2F 9 sakai28.areaimpl3_.ID 1 Using
> >> where; Using index
> >> 1 SIMPLE topicimpl0_ ref PRIMARY,FK863DC0BE74C7E92B
> >> FK863DC0BE74C7E92B 9 sakai28.openforumi2_.ID 37 Using
> >> where
> >> 1 SIMPLE membership4_ ref
> >> PERMISSION_LEVEL,FKE03761CB7DEF8466,FKE03761CB88085F8E
> FKE03761CB7DEF8466
> >> 9 sakai28.topicimpl0_.ID 6 Using
> >> where
> >> 1 SIMPLE permission1_ eq_ref
> PRIMARY,MFR_MODERATE_POSTINGS_IDX
> >> PRIMARY 8 sakai28.membership4_.PERMISSION_LEVEL 1
> Using
> >> where
> >>
> >> On Wed, Sep 7, 2011 at 10:33 AM, Earle Nietzel <earle.nietzel at gmail.com
> >
> >> wrote:
> >> > Hi Bryan,
> >> >
> >> > (I had also included it the original post)
> >> >
> >> > The only thing I added was the straight_join (MySQL specific). Take a
> >> > look
> >> > last query seems to be the better performer.
> >> >
> >> > Original query:
> >> >
> >> > select count(*) as col_0_0_
> >> > from MFR_TOPIC_T topicimpl0_
> >> > inner join MFR_OPEN_FORUM_T openforumi2_ on
> >> > topicimpl0_.of_surrogateKey=openforumi2_.ID
> >> > inner join MFR_AREA_T areaimpl3_ on
> >> > openforumi2_.surrogateKey=areaimpl3_.ID
> >> > inner join MFR_MEMBERSHIP_ITEM_T membership4_ on
> >> > topicimpl0_.ID=membership4_.t_surrogateKey,
> >> > MFR_PERMISSION_LEVEL_T permission1_
> >> > where areaimpl3_.CONTEXT_ID='517f8f28-f68e-42ee-b168-919a06f82229'
> >> > and topicimpl0_.MODERATED=1
> >> > and (membership4_.NAME in ('Student' , 'MATH_111L_114_11F'))
> >> > and permission1_.MODERATE_POSTINGS=1
> >> > and permission1_.TYPE_UUID!='00000000-0000-0000-7777-000000000000'
> >> > and permission1_.NAME=membership4_.PERMISSION_LEVEL_NAME
> >> >
> >> >
> >> >
> >> > Query with straight_join added:
> >> >
> >> > select straight_join count(*) as col_0_0_
> >> > from MFR_TOPIC_T topicimpl0_
> >> > inner join MFR_OPEN_FORUM_T openforumi2_ on
> >> > topicimpl0_.of_surrogateKey=openforumi2_.ID
> >> > inner join MFR_AREA_T areaimpl3_ on
> >> > openforumi2_.surrogateKey=areaimpl3_.ID
> >> > inner join MFR_MEMBERSHIP_ITEM_T membership4_ on
> >> > topicimpl0_.ID=membership4_.t_surrogateKey,
> >> > MFR_PERMISSION_LEVEL_T permission1_
> >> > where areaimpl3_.CONTEXT_ID='517f8f28-f68e-42ee-b168-919a06f82229'
> >> > and topicimpl0_.MODERATED=1
> >> > and (membership4_.NAME in ('Student' , 'MATH_111L_114_11F'))
> >> > and permission1_.MODERATE_POSTINGS=1
> >> > and permission1_.TYPE_UUID!='00000000-0000-0000-7777-000000000000'
> >> > and permission1_.NAME=membership4_.PERMISSION_LEVEL_NAME
> >> >
> >> >
> >> > This query with a straight_join seems to out perform the query above
> and
> >> > its
> >> > query plan matches that of the original query when the original runs
> >> > well:
> >> > (I would recommend this query)
> >> >
> >> > select straight_join count(topicimpl0_.ID) as col_0_0_
> >> > from MFR_AREA_T areaimpl3_
> >> > inner join MFR_OPEN_FORUM_T openforumi2_ on
> >> > openforumi2_.surrogateKey=areaimpl3_.ID
> >> > inner join MFR_TOPIC_T topicimpl0_ on
> >> > topicimpl0_.of_surrogateKey=openforumi2_.ID
> >> > inner join MFR_MEMBERSHIP_ITEM_T membership4_ on
> >> > topicimpl0_.ID=membership4_.t_surrogateKey,
> >> > MFR_PERMISSION_LEVEL_T permission1_
> >> > where areaimpl3_.CONTEXT_ID='517f8f28-f68e-42ee-b168-919a06f82229'
> >> > and topicimpl0_.MODERATED=1
> >> > and (membership4_.NAME in ('Student' , 'MATH_111L_114_11F'))
> >> > and permission1_.MODERATE_POSTINGS=1
> >> > and permission1_.TYPE_UUID!='00000000-0000-0000-7777-000000000000'
> >> > and permission1_.NAME=membership4_.PERMISSION_LEVEL_NAME
> >> >
> >> > Earle
> >> >
> >> > On Wed, Sep 7, 2011 at 8:12 AM, Bryan Holladay <
> holladay at longsight.com>
> >> > wrote:
> >> >>
> >> >> Earle,
> >> >>
> >> >> Could you send me both queries:
> >> >>
> >> >> 1) the slow query that Sakai uses (the actual SQL query, not the
> >> >> hibernate query. You can get this by setting hibernate.show_sql=true
> >> >> in the sakai.properties (DO NOT SET THIS IN PRD!!!) and watch the
> >> >> logs).
> >> >>
> >> >> 2) your new join query to resolve this (actual SQL)
> >> >>
> >> >> Then I can look at the query plans on my local machine to see how the
> >> >> index's pan out.
> >> >>
> >> >> Thanks,
> >> >> Bryan
> >> >>
> >> >> On Tue, Sep 6, 2011 at 5:48 PM, Earle Nietzel <
> earle.nietzel at gmail.com>
> >> >> wrote:
> >> >> > Hi Bryan.
> >> >> >
> >> >> > I have included the create statements from our DB (see below
> inline).
> >> >> >
> >> >> > Everything matches up except we have a few additional Foreign Keys
> >> >> > while you didn't mention the other tables I am assuming that they
> are
> >> >> > fine.
> >> >> >
> >> >> > On the side I did a hbm2ddl and it seems that more indexes are
> >> >> > definitely created according to hibernate.
> >> >> >
> >> >> > I realize this issue is a bit strange but I don't believe there to
> be
> >> >> > a problem with sakai but rather mysql.
> >> >> >
> >> >> > So I suggested a workaround for mysql using a straight_join.
> >> >> >
> >> >> > I am not sure if that is the best idea or maybe rework the query so
> >> >> > that mysql doesn't get into a situation of picking a bad query
> plan.
> >> >> >
> >> >> > Earle
> >> >> >
> >> >> > BTW We are using mysql-5.1.52-1.el6_0.1.x86_64
> >> >> >
> >> >> > On Tue, Sep 6, 2011 at 8:24 AM, Bryan Holladay
> >> >> > <holladay at longsight.com>
> >> >> > wrote:
> >> >> >>
> >> >> >> What index's do you have set? This has a huge effect on query
> plans
> >> >> >> and most people have too many index's set. Make sure you only
> have
> >> >> >> these index's and then look at the query plan:
> >> >> >>
> >> >> >> CREATE INDEX MFR_UNREAD_STATUS_I2 USING BTREE
> >> >> >> ON MFR_UNREAD_STATUS_T(MESSAGE_C, USER_C, READ_C);
> >> >> >>
> >> >> >> CREATE INDEX MFR_UNREAD_STATUS_I1 USING BTREE
> >> >> >> ON MFR_UNREAD_STATUS_T(TOPIC_C, MESSAGE_C, USER_C, READ_C);
> >> >> >>
> >> >> >> CREATE UNIQUE INDEX PRIMARY USING BTREE
> >> >> >> ON MFR_UNREAD_STATUS_T(ID);
> >> >> >>
> >> >> >> ALTER TABLE MFR_UNREAD_STATUS_T
> >> >> >> ADD CONSTRAINT TOPIC_C
> >> >> >> UNIQUE (TOPIC_C, MESSAGE_C, USER_C);
> >> >> >
> >> >> > | MFR_UNREAD_STATUS_T | CREATE TABLE `mfr_unread_status_t` (
> >> >> > `ID` bigint(20) NOT NULL AUTO_INCREMENT,
> >> >> > `VERSION` int(11) NOT NULL,
> >> >> > `TOPIC_C` bigint(20) NOT NULL,
> >> >> > `MESSAGE_C` bigint(20) NOT NULL,
> >> >> > `USER_C` varchar(255) NOT NULL,
> >> >> > `READ_C` bit(1) NOT NULL,
> >> >> > PRIMARY KEY (`ID`),
> >> >> > UNIQUE KEY `TOPIC_C` (`TOPIC_C`,`MESSAGE_C`,`USER_C`),
> >> >> > KEY `MFR_UNREAD_STATUS_I2` (`MESSAGE_C`,`USER_C`,`READ_C`),
> >> >> > KEY `MFR_UNREAD_STATUS_I1`
> >> >> > (`TOPIC_C`,`MESSAGE_C`,`USER_C`,`READ_C`)
> >> >> > USING BTREE
> >> >> > ) ENGINE=InnoDB AUTO_INCREMENT=5750248 DEFAULT CHARSET=utf8 |
> >> >> >
> >> >> >
> >> >> >>
> >> >> >> ALTER TABLE MFR_MESSAGE_T
> >> >> >> ADD CONSTRAINT FK80C1A316A2D0BE7B
> >> >> >> FOREIGN KEY(surrogateKey)
> >> >> >> REFERENCES MFR_TOPIC_T(ID);
> >> >> >>
> >> >> >
> >> >> > | MFR_MESSAGE_T | CREATE TABLE `mfr_message_t` (
> >> >> > `ID` bigint(20) NOT NULL AUTO_INCREMENT,
> >> >> > `MESSAGE_DTYPE` varchar(2) NOT NULL,
> >> >> > `VERSION` int(11) NOT NULL,
> >> >> > `UUID` varchar(36) NOT NULL,
> >> >> > `CREATED` datetime NOT NULL,
> >> >> > `CREATED_BY` varchar(36) NOT NULL,
> >> >> > `MODIFIED` datetime NOT NULL,
> >> >> > `MODIFIED_BY` varchar(36) NOT NULL,
> >> >> > `TITLE` varchar(255) NOT NULL,
> >> >> > `BODY` text,
> >> >> > `AUTHOR` varchar(255) NOT NULL,
> >> >> > `HAS_ATTACHMENTS` bit(1) NOT NULL,
> >> >> > `GRADEASSIGNMENTNAME` varchar(255) DEFAULT NULL,
> >> >> > `LABEL` varchar(255) DEFAULT NULL,
> >> >> > `IN_REPLY_TO` bigint(20) DEFAULT NULL,
> >> >> > `TYPE_UUID` varchar(36) NOT NULL,
> >> >> > `APPROVED` bit(1) DEFAULT NULL,
> >> >> > `DRAFT` bit(1) NOT NULL,
> >> >> > `surrogateKey` bigint(20) DEFAULT NULL,
> >> >> > `EXTERNAL_EMAIL` bit(1) DEFAULT NULL,
> >> >> > `EXTERNAL_EMAIL_ADDRESS` varchar(255) DEFAULT NULL,
> >> >> > `RECIPIENTS_AS_TEXT` text,
> >> >> > `DELETED` bit(1) NOT NULL DEFAULT b'0',
> >> >> > `NUM_READERS` int(11) DEFAULT NULL,
> >> >> > `THREADID` bigint(20) DEFAULT NULL,
> >> >> > `LASTTHREADATE` datetime DEFAULT NULL,
> >> >> > `LASTTHREAPOST` bigint(20) DEFAULT NULL,
> >> >> > PRIMARY KEY (`ID`),
> >> >> > KEY `FK80C1A31650339D56` (`IN_REPLY_TO`),
> >> >> > KEY `FK80C1A316A2D0BE7B` (`surrogateKey`),
> >> >> > KEY `MFR_MESSAGE_DELETED_I` (`DELETED`),
> >> >> > KEY `MFR_MESSAGE_T_IN_REPLY_TO_I` (`IN_REPLY_TO`),
> >> >> > KEY `mfrmessageindex2` (`CREATED_BY`),
> >> >> > CONSTRAINT `FK80C1A31650339D56` FOREIGN KEY (`IN_REPLY_TO`)
> >> >> > REFERENCES `mfr_message_t` (`ID`),
> >> >> > CONSTRAINT `FK80C1A316A2D0BE7B` FOREIGN KEY (`surrogateKey`)
> >> >> > REFERENCES `mfr_topic_t` (`ID`)
> >> >> > ) ENGINE=InnoDB AUTO_INCREMENT=1196102 DEFAULT CHARSET=utf8 |
> >> >> >
> >> >> >
> >> >> >>
> >> >> >> ALTER TABLE MFR_TOPIC_T
> >> >> >> ADD CONSTRAINT FK863DC0BE74C7E92B
> >> >> >> FOREIGN KEY(of_surrogateKey)
> >> >> >> REFERENCES MFR_OPEN_FORUM_T(ID);
> >> >> >>
> >> >> >
> >> >> > | MFR_TOPIC_T | CREATE TABLE `mfr_topic_t` (
> >> >> > `ID` bigint(20) NOT NULL AUTO_INCREMENT,
> >> >> > `TOPIC_DTYPE` varchar(2) NOT NULL,
> >> >> > `VERSION` int(11) NOT NULL,
> >> >> > `UUID` varchar(36) NOT NULL,
> >> >> > `CREATED` datetime NOT NULL,
> >> >> > `CREATED_BY` varchar(36) NOT NULL,
> >> >> > `MODIFIED` datetime NOT NULL,
> >> >> > `MODIFIED_BY` varchar(36) NOT NULL,
> >> >> > `DEFAULTASSIGNNAME` varchar(255) DEFAULT NULL,
> >> >> > `TITLE` varchar(255) NOT NULL,
> >> >> > `SHORT_DESCRIPTION` varchar(255) DEFAULT NULL,
> >> >> > `EXTENDED_DESCRIPTION` text,
> >> >> > `MODERATED` bit(1) NOT NULL,
> >> >> > `MUTABLE` bit(1) NOT NULL,
> >> >> > `SORT_INDEX` int(11) NOT NULL,
> >> >> > `TYPE_UUID` varchar(36) NOT NULL,
> >> >> > `of_surrogateKey` bigint(20) DEFAULT NULL,
> >> >> > `pf_surrogateKey` bigint(20) DEFAULT NULL,
> >> >> > `USER_ID` varchar(255) DEFAULT NULL,
> >> >> > `CONTEXT_ID` varchar(36) DEFAULT NULL,
> >> >> > `pt_surrogateKey` bigint(20) DEFAULT NULL,
> >> >> > `LOCKED` bit(1) DEFAULT NULL,
> >> >> > `DRAFT` bit(1) DEFAULT NULL,
> >> >> > `CONFIDENTIAL_RESPONSES` bit(1) DEFAULT NULL,
> >> >> > `MUST_RESPOND_BEFORE_READING` bit(1) DEFAULT NULL,
> >> >> > `HOUR_BEFORE_RESPONSES_VISIBLE` int(11) DEFAULT NULL,
> >> >> > `AUTO_MARK_THREADS_READ` bit(1) NOT NULL,
> >> >> > `AVAILABILITY_RESTRICTED` bit(1) NOT NULL DEFAULT b'0',
> >> >> > `AVAILABILITY` bit(1) NOT NULL DEFAULT b'1',
> >> >> > `OPEN_DATE` datetime DEFAULT NULL,
> >> >> > `CLOSE_DATE` datetime DEFAULT NULL,
> >> >> > PRIMARY KEY (`ID`),
> >> >> > KEY `FK863DC0BE82FAB29` (`pf_surrogateKey`),
> >> >> > KEY `FK863DC0BEFF3B3AE9` (`pt_surrogateKey`),
> >> >> > KEY `FK863DC0BE74C7E92B` (`of_surrogateKey`),
> >> >> > KEY `MFR_TOPIC_T_UUID_I` (`UUID`),
> >> >> > CONSTRAINT `FK863DC0BE74C7E92B` FOREIGN KEY (`of_surrogateKey`)
> >> >> > REFERENCES `mfr_open_forum_t` (`ID`),
> >> >> > CONSTRAINT `FK863DC0BE82FAB29` FOREIGN KEY (`pf_surrogateKey`)
> >> >> > REFERENCES `mfr_private_forum_t` (`ID`),
> >> >> > CONSTRAINT `FK863DC0BEFF3B3AE9` FOREIGN KEY (`pt_surrogateKey`)
> >> >> > REFERENCES `mfr_topic_t` (`ID`)
> >> >> > ) ENGINE=InnoDB AUTO_INCREMENT=574313 DEFAULT CHARSET=utf8 |
> >> >> >
> >> >> >
> >> >> >>
> >> >> >> ALTER TABLE MFR_OPEN_FORUM_T
> >> >> >> ADD CONSTRAINT FKC17608478B5E2A2F
> >> >> >> FOREIGN KEY(surrogateKey)
> >> >> >> REFERENCES MFR_AREA_T(ID);
> >> >> >>
> >> >> >
> >> >> > | MFR_OPEN_FORUM_T | CREATE TABLE `mfr_open_forum_t` (
> >> >> > `ID` bigint(20) NOT NULL AUTO_INCREMENT,
> >> >> > `FORUM_DTYPE` varchar(2) NOT NULL,
> >> >> > `VERSION` int(11) NOT NULL,
> >> >> > `UUID` varchar(36) NOT NULL,
> >> >> > `CREATED` datetime NOT NULL,
> >> >> > `CREATED_BY` varchar(36) NOT NULL,
> >> >> > `MODIFIED` datetime NOT NULL,
> >> >> > `MODIFIED_BY` varchar(36) NOT NULL,
> >> >> > `DEFAULTASSIGNNAME` varchar(255) DEFAULT NULL,
> >> >> > `TITLE` varchar(255) NOT NULL,
> >> >> > `SHORT_DESCRIPTION` varchar(255) DEFAULT NULL,
> >> >> > `EXTENDED_DESCRIPTION` text,
> >> >> > `TYPE_UUID` varchar(36) NOT NULL,
> >> >> > `SORT_INDEX` int(11) NOT NULL,
> >> >> > `LOCKED` bit(1) NOT NULL,
> >> >> > `DRAFT` bit(1) DEFAULT NULL,
> >> >> > `surrogateKey` bigint(20) DEFAULT NULL,
> >> >> > `MODERATED` bit(1) NOT NULL,
> >> >> > `AUTO_MARK_THREADS_READ` bit(1) NOT NULL,
> >> >> > `AVAILABILITY_RESTRICTED` bit(1) NOT NULL DEFAULT b'0',
> >> >> > `AVAILABILITY` bit(1) NOT NULL DEFAULT b'1',
> >> >> > `OPEN_DATE` datetime DEFAULT NULL,
> >> >> > `CLOSE_DATE` datetime DEFAULT NULL,
> >> >> > PRIMARY KEY (`ID`),
> >> >> > KEY `FKC17608478B5E2A2F` (`surrogateKey`),
> >> >> > CONSTRAINT `FKC17608478B5E2A2F` FOREIGN KEY (`surrogateKey`)
> >> >> > REFERENCES `mfr_area_t` (`ID`)
> >> >> > ) ENGINE=InnoDB AUTO_INCREMENT=17835 DEFAULT CHARSET=utf8 |
> >> >> >
> >> >> >
> >> >> >>
> >> >> >> ALTER TABLE MFR_AREA_T
> >> >> >> ADD CONSTRAINT MFR_AREA_CONTEXT_UUID_UNIQUE
> >> >> >> UNIQUE (CONTEXT_ID, TYPE_UUID);
> >> >> >>
> >> >> >
> >> >> > | MFR_AREA_T | CREATE TABLE `mfr_area_t` (
> >> >> > `ID` bigint(20) NOT NULL AUTO_INCREMENT,
> >> >> > `VERSION` int(11) NOT NULL,
> >> >> > `UUID` varchar(36) NOT NULL,
> >> >> > `CREATED` datetime NOT NULL,
> >> >> > `CREATED_BY` varchar(36) NOT NULL,
> >> >> > `MODIFIED` datetime NOT NULL,
> >> >> > `MODIFIED_BY` varchar(36) NOT NULL,
> >> >> > `CONTEXT_ID` varchar(255) NOT NULL,
> >> >> > `NAME` varchar(255) NOT NULL,
> >> >> > `HIDDEN` bit(1) NOT NULL,
> >> >> > `TYPE_UUID` varchar(36) NOT NULL,
> >> >> > `ENABLED` bit(1) NOT NULL,
> >> >> > `LOCKED` bit(1) NOT NULL,
> >> >> > `MODERATED` bit(1) NOT NULL,
> >> >> > `SENDEMAILOUT` bit(1) NOT NULL,
> >> >> > `AUTO_MARK_THREADS_READ` bit(1) NOT NULL,
> >> >> > `AVAILABILITY_RESTRICTED` bit(1) NOT NULL DEFAULT b'0',
> >> >> > `AVAILABILITY` bit(1) NOT NULL DEFAULT b'1',
> >> >> > `OPEN_DATE` datetime DEFAULT NULL,
> >> >> > `CLOSE_DATE` datetime DEFAULT NULL,
> >> >> > PRIMARY KEY (`ID`),
> >> >> > UNIQUE KEY `MFR_AREA_CONTEXT_UUID_UNIQUE`
> >> >> > (`CONTEXT_ID`,`TYPE_UUID`),
> >> >> > KEY `CONTEXT_ID` (`CONTEXT_ID`(20))
> >> >> > ) ENGINE=InnoDB AUTO_INCREMENT=12227 DEFAULT CHARSET=utf8 |
> >> >> >
> >> >> >
> >> >> >>
> >> >> >> On Fri, Sep 2, 2011 at 4:15 PM, Earle Nietzel
> >> >> >> <earle.nietzel at gmail.com>
> >> >> >> wrote:
> >> >> >> > Here is the version from the pom:
> >> >> >> >
> >> >> >> > <name>Sakai Message Center Base POM</name>
> >> >> >> > <groupId>org.sakaiproject.msgcntr</groupId>
> >> >> >> > <version>2.8.0-rc04</version>
> >> >> >> > <artifactId>msgcntr</artifactId>
> >> >> >> > <packaging>pom</packaging>
> >> >> >> >
> >> >> >> > Earle
> >> >> >> >
> >> >> >> > On Fri, Sep 2, 2011 at 4:08 PM, Sam Ottenhoff
> >> >> >> > <ottenhoff at longsight.com>
> >> >> >> > wrote:
> >> >> >> >>
> >> >> >> >> What version of MsgCntr? Do you see the same issue on trunk
> >> >> >> >> MsgCntr?
> >> >> >> >> Note that MsgCntr 2.7.0 has major performance issues and should
> >> >> >> >> not
> >> >> >> >> be run
> >> >> >> >> in any type of serious production environment.
> >> >> >> >> --Sam
> >> >> >> >>
> >> >> >> >> On Fri, Sep 2, 2011 at 3:51 PM, Earle Nietzel
> >> >> >> >> <earle.nietzel at gmail.com>
> >> >> >> >> wrote:
> >> >> >> >>>
> >> >> >> >>> Hello everyone,
> >> >> >> >>>
> >> >> >> >>> Got a bit of an issue here with forums and a particular query
> >> >> >> >>> that
> >> >> >> >>> mysql
> >> >> >> >>> is coming up with different query plans. Depending on which
> one
> >> >> >> >>> it
> >> >> >> >>> selects
> >> >> >> >>> it can take a significant amount of time to complete.
> >> >> >> >>>
> >> >> >> >>> The hql in question (added from MSGCNTR-364):
> >> >> >> >>>
> >> >> >> >>> <query
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> name="findNumModeratedTopicsForSiteByUserByMembershipWithPermissionLevelName">
> >> >> >> >>> <![CDATA[select count(*) from
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> org.sakaiproject.component.app.messageforums.dao.hibernate.TopicImpl as
> >> >> >> >>> topic,
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> org.sakaiproject.component.app.messageforums.dao.hibernate.PermissionLevelImpl
> >> >> >> >>> as pl
> >> >> >> >>> join topic.openForum as forum
> >> >> >> >>> join forum.area as area
> >> >> >> >>> join topic.membershipItemSet as membershipItem
> >> >> >> >>> where area.contextId = :contextId and
> >> >> >> >>> topic.moderated = true and
> >> >> >> >>> membershipItem.name in ( :membershipList ) and
> >> >> >> >>> pl.moderatePostings = true and
> >> >> >> >>> (pl.typeUuid != :customTypeUuid and
> >> >> >> >>> pl.name = membershipItem.permissionLevelName)
> >> >> >> >>> ]]>
> >> >> >> >>> </query>
> >> >> >> >>>
> >> >> >> >>> Which then is compiled into this SQL:
> >> >> >> >>>
> >> >> >> >>> select count(*) as col_0_0_
> >> >> >> >>> from MFR_TOPIC_T topicimpl0_
> >> >> >> >>> inner join MFR_OPEN_FORUM_T openforumi2_ on
> >> >> >> >>> topicimpl0_.of_surrogateKey=openforumi2_.ID
> >> >> >> >>> inner join MFR_AREA_T areaimpl3_ on
> >> >> >> >>> openforumi2_.surrogateKey=areaimpl3_.ID
> >> >> >> >>> inner join MFR_MEMBERSHIP_ITEM_T membership4_ on
> >> >> >> >>> topicimpl0_.ID=membership4_.t_surrogateKey,
> >> >> >> >>> MFR_PERMISSION_LEVEL_T permission1_
> >> >> >> >>> where
> >> >> >> >>> areaimpl3_.CONTEXT_ID='517f8f28-f68e-42ee-b168-919a06f82229'
> >> >> >> >>> and topicimpl0_.MODERATED=1
> >> >> >> >>> and (membership4_.NAME in ('Student' , 'MATH_111L_114_11F'))
> >> >> >> >>> and permission1_.MODERATE_POSTINGS=1
> >> >> >> >>> and
> >> >> >> >>> permission1_.TYPE_UUID!='00000000-0000-0000-7777-000000000000'
> >> >> >> >>> and permission1_.NAME=membership4_.PERMISSION_LEVEL_NAME
> >> >> >> >>>
> >> >> >> >>> The efficient query plan looks like:
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> +----+-------------+--------------+------+-------------------------------------------------+------------------------------+---------+-------------------------------------------+-------+--------------------------+
> >> >> >> >>> | id | select_type | table | type |
> >> >> >> >>> possible_keys |
> >> >> >> >>> key | key_len |
> >> >> >> >>> ref | rows | Extra
> >> >> >> >>> |
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> +----+-------------+--------------+------+-------------------------------------------------+------------------------------+---------+-------------------------------------------+-------+--------------------------+
> >> >> >> >>> | 1 | SIMPLE | areaimpl3_ | ref |
> >> >> >> >>> PRIMARY,MFR_AREA_CONTEXT_UUID_UNIQUE,CONTEXT_ID |
> >> >> >> >>> MFR_AREA_CONTEXT_UUID_UNIQUE | 767 |
> >> >> >> >>> const | 2 | Using
> where;
> >> >> >> >>> Using index
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | openforumi2_ | ref |
> >> >> >> >>> PRIMARY,FKC17608478B5E2A2F |
> >> >> >> >>> FKC17608478B5E2A2F | 9 |
> >> >> >> >>> ilearn.areaimpl3_.ID | 3 | Using
> where;
> >> >> >> >>> Using index
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | topicimpl0_ | ref |
> >> >> >> >>> PRIMARY,FK863DC0BE74C7E92B |
> >> >> >> >>> FK863DC0BE74C7E92B | 9 |
> >> >> >> >>> ilearn.openforumi2_.ID | 35 | Using
> where
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | membership4_ | ref |
> >> >> >> >>> FKE03761CB7DEF8466,MFRMEMITEM_COMPOSITE_IDX1 |
> >> >> >> >>> FKE03761CB7DEF8466 | 9 |
> >> >> >> >>> ilearn.topicimpl0_.ID | 3 | Using
> where
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | permission1_ | ref |
> >> >> >> >>> MFRPERMLVL_COMPOSITE_IDX1 |
> >> >> >> >>> MFRPERMLVL_COMPOSITE_IDX1 | 152 |
> >> >> >> >>> ilearn.membership4_.PERMISSION_LEVEL_NAME | 10167 | Using
> where
> >> >> >> >>> |
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> +----+-------------+--------------+------+-------------------------------------------------+------------------------------+---------+-------------------------------------------+-------+--------------------------+
> >> >> >> >>>
> >> >> >> >>> The problem occurs when mysql selects a query plan where
> tables
> >> >> >> >>> membership4_ and permission1_ are not at the end but towards
> the
> >> >> >> >>> top of the
> >> >> >> >>> query plan (this query takes several minutes to run):
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> +----+-------------+--------------+--------+-------------------------------------------------+---------------------------+---------+-------------------------------------------+-------+-------------+
> >> >> >> >>> | id | select_type | table | type |
> >> >> >> >>> possible_keys | key
> >> >> >> >>> | key_len | ref | rows
> |
> >> >> >> >>> Extra
> >> >> >> >>> |
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> +----+-------------+--------------+--------+-------------------------------------------------+---------------------------+---------+-------------------------------------------+-------+-------------+
> >> >> >> >>> | 1 | SIMPLE | membership4_ | range |
> >> >> >> >>> FKE03761CB7DEF8466,MFRMEMITEM_COMPOSITE_IDX1 |
> >> >> >> >>> MFRMEMITEM_COMPOSITE_IDX1
> >> >> >> >>> | 767 |NULL | 67305
> |
> >> >> >> >>> Using where
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | permission1_ | ref |
> >> >> >> >>> MFRPERMLVL_NAME_IDX |
> >> >> >> >>> MFRPERMLVL_NAME_IDX
> >> >> >> >>> | 152 | ilearn.membership4_.PERMISSION_LEVEL_NAME | 22004
> |
> >> >> >> >>> Using where
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | topicimpl0_ | eq_ref |
> >> >> >> >>> PRIMARY,FK863DC0BE74C7E92B | PRIMARY
> >> >> >> >>> | 8 | ilearn.membership4_.t_surrogateKey | 1
> |
> >> >> >> >>> Using where
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | openforumi2_ | eq_ref |
> >> >> >> >>> PRIMARY,FKC17608478B5E2A2F | PRIMARY
> >> >> >> >>> | 8 | ilearn.topicimpl0_.of_surrogateKey | 1
> |
> >> >> >> >>> Using where
> >> >> >> >>> |
> >> >> >> >>> | 1 | SIMPLE | areaimpl3_ | eq_ref |
> >> >> >> >>> PRIMARY,MFR_AREA_CONTEXT_UUID_UNIQUE,CONTEXT_ID | PRIMARY
> >> >> >> >>> | 8 | ilearn.openforumi2_.surrogateKey | 1
> |
> >> >> >> >>> Using where
> >> >> >> >>> |
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> +----+-------------+--------------+--------+-------------------------------------------------+---------------------------+---------+-------------------------------------------+-------+-------------+
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>> At the moment the only way I've been able to make sure mysql
> >> >> >> >>> doesn't
> >> >> >> >>> select the slow query plan is to use straight_join but it
> >> >> >> >>> appears
> >> >> >> >>> this is
> >> >> >> >>> specific to mysql and therefore not supported by hibernate.
> >> >> >> >>>
> >> >> >> >>> Do we need a to implement a native query specific for MySQL in
> >> >> >> >>> this
> >> >> >> >>> case?
> >> >> >> >>>
> >> >> >> >>> Here is some psuedo code to represent what I am thinking:
> >> >> >> >>>
> >> >> >> >>> HibernateCallback hcb = new HibernateCallback() {
> >> >> >> >>> public Object doInHibernate(Session session) throws
> >> >> >> >>> HibernateException,
> >> >> >> >>> SQLException {
> >> >> >> >>> if
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> ("mysql".equals(serverConfigurationService.getString(vendor at org.sakaiproject.db.api.SqlService
> ))
> >> >> >> >>> Query q =
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> session.createSQLQuery(MYSQL_QUERY_GET_NUM_MOD_TOPICS_WITH_MOD_PERM_BY_PERM_LEVEL_NAME);
> >> >> >> >>> else
> >> >> >> >>> Query q =
> >> >> >> >>>
> >> >> >> >>>
> >> >> >> >>>
> session.getNamedQuery(QUERY_GET_NUM_MOD_TOPICS_WITH_MOD_PERM_BY_PERM_LEVEL_NAME);
> >> >> >> >>> q.setParameterList("membershipList", membershipList);
> >> >> >> >>> q.setParameter("contextId", getContextId(),
> >> >> >> >>> Hibernate.STRING);
> >> >> >> >>> q.setParameter("customTypeUuid",
> >> >> >> >>> typeManager.getCustomLevelType(),
> >> >> >> >>> Hibernate.STRING);
> >> >> >> >>> return q.uniqueResult();
> >> >> >> >>> }
> >> >> >> >>> };
> >> >> >> >>>
> >> >> >> >>> Ideas and thoughts most welcome,
> >> >> >> >>> Earle
> >> >> >> >>>
> >> >> >> >>> _______________________________________________
> >> >> >> >>> sakai-dev mailing list
> >> >> >> >>> sakai-dev at collab.sakaiproject.org
> >> >> >> >>> http://collab.sakaiproject.org/mailman/listinfo/sakai-dev
> >> >> >> >>>
> >> >> >> >>> TO UNSUBSCRIBE: send email to
> >> >> >> >>> sakai-dev-unsubscribe at collab.sakaiproject.org with a subject
> of
> >> >> >> >>> "unsubscribe"
> >> >> >> >>
> >> >> >> >
> >> >> >> >
> >> >> >> > _______________________________________________
> >> >> >> > sakai-dev mailing list
> >> >> >> > sakai-dev at collab.sakaiproject.org
> >> >> >> > http://collab.sakaiproject.org/mailman/listinfo/sakai-dev
> >> >> >> >
> >> >> >> > TO UNSUBSCRIBE: send email to
> >> >> >> > sakai-dev-unsubscribe at collab.sakaiproject.org
> >> >> >> > with a subject of "unsubscribe"
> >> >> >> >
> >> >> >
> >> >
> >> >
> >
> >
>
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