Skip site navigation (1) Skip section navigation (2)

Re: Full Text index is not using during OR operation

From: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
To: AI Rumman <rummandba(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Full Text index is not using during OR operation
Date: 2010-11-29 15:02:50
Message-ID: Pine.LNX.4.64.1011291801410.12632@sn.sai.msu.ru (view raw or flat)
Thread:
Lists: pgsql-performance
On Mon, 29 Nov 2010, AI Rumman wrote:

> Oh! Actualy it is:
> select replace('Dhaka University of Bangladesh:*', ' ',':* & ');
> No space at start.

So, what are actual problems with full text ? I mostly interesting with 
server crush. We need test data, test query and error message.


>
> On Mon, Nov 29, 2010 at 6:37 PM, Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> wrote:
>
>> What does replace(' Dhaka University of Bangladesh:*', ' ',':* & ') means ?
>> I see it produces something wrong for to_tsquery:
>>
>> test=# select replace(' Dhaka University of Bangladesh:*', ' ',':* & ');
>>
>>                      replace
>> ---------------------------------------------------
>>  :* & Dhaka:* & University:* & of:* & Bangladesh:*
>> (1 row)
>>
>> Oleg
>>
>>
>> On Mon, 29 Nov 2010, AI Rumman wrote:
>>
>>  explain
>>> SELECT crmentity.crmid, crmentity.setype, crmentity.modifiedtime,
>>> activity.subject,case when ( users.user_name not like '') then
>>> users.user_name else groups.groupname end as user_name,
>>> activity.date_start
>>> FROM crmentity INNER JOIN activity ON crmentity.crmid =
>>> activity.activityid
>>> and crmentity.deleted = 0
>>> LEFT JOIN activitygrouprelation ON activitygrouprelation.activityid =
>>> crmentity.crmid
>>> LEFT JOIN groups ON groups.groupname = activitygrouprelation.groupname
>>> LEFT join users ON crmentity.smownerid= users.id
>>> WHERE
>>> to_tsvector(' en', for_fts( activity.subject)) @@ to_tsquery(' en',
>>> replace(' Dhaka University of Bangladesh:*', ' ',':* & '))
>>> or
>>> to_tsvector(' en', for_fts( crmentity.description)) @@ to_tsquery(' en',
>>> replace(' Dhaka University of Bangladesh:*', ' ',':* & '))
>>> ORDER BY crmentity.modifiedtime DESC LIMIT 100
>>>
>>>  QUERY PLAN
>>>
>>>
>>> ------------------------------------------------------------------------------------------------------------------------------------------
>>> Limit (cost=112724.54..112724.54 rows=1 width=99)
>>>  -> Sort (cost=112724.54..112724.54 rows=1 width=99)
>>>  Sort Key: crmentity.modifiedtime
>>>  -> Nested Loop Left Join (cost=0.00..112724.53 rows=1 width=99)
>>>  -> Nested Loop Left Join (cost=0.00..112724.24 rows=1 width=82)
>>>  -> Nested Loop Left Join (cost=0.00..112723.96 rows=1 width=79)
>>>  -> Nested Loop (cost=0.00..112723.68 rows=1 width=56)
>>>  Join Filter: ((to_tsvector('en'::regconfig,
>>> regexp_replace((activity.subject)::text,
>>> '(&[^;]+;)|(<[^>]+>)|([\\s\\r\\n\\t]+)'::text, ''::text, 'gs'::text)) @@
>>> '''
>>> Dhaka'':* & ''univers'':* & ''bangladesh'':*'::tsquery) OR
>>> (to_tsvector('en'::regconfig, regexp_replace(crmentity.description,
>>> '(&[^;]+;)|(<[^>]+>)|([\\s\\r\\n\\t]+)'::text, ' '::text, 'gs'::text)) @@
>>> ''' Dhaka'':* & ''univers'':* & ''bangladesh'':*'::tsquery))
>>>  -> Index Scan using activity_pkey on activity (cost=0.00..10223.89
>>> rows=343070 width=36)
>>>  -> Index Scan using crmentity_pkey on crmentity (cost=0.00..0.27 rows=1
>>> width=151)
>>>  Index Cond: (crmentity.crmid = activity.activityid)
>>>  Filter: (crmentity.deleted = 0)
>>>  -> Index Scan using activitygrouprelation_activityid_idx on
>>> activitygrouprelation (cost=0.00..0.27 rows=1 width=27)
>>>  Index Cond: (activitygrouprelation.activityid = crmentity.crmid)
>>>  -> Index Scan using groups_groupname_idx on groups (cost=0.00..0.27
>>> rows=1
>>> width=26)
>>>  Index Cond: ((groups.groupname)::text =
>>> (activitygrouprelation.groupname)::text)
>>>  -> Index Scan using users_pkey on users (cost=0.00..0.27 rows=1 width=25)
>>>  Index Cond: (crmentity.smownerid = users.id)
>>>
>>>
>>> The above query are not using fts indexes, even hang the server.
>>>
>>> But,
>>>
>>>
>>> explain
>>> SELECT crmentity.crmid, crmentity.setype, crmentity.modifiedtime,
>>> activity.subject,case when ( users.user_name not like '') then
>>> users.user_name else groups.groupname end as user_name,
>>> activity.date_start
>>> FROM crmentity INNER JOIN activity ON crmentity.crmid =
>>> activity.activityid
>>> and crmentity.deleted = 0
>>> LEFT JOIN activitygrouprelation ON activitygrouprelation.activityid =
>>> crmentity.crmid
>>> LEFT JOIN groups ON groups.groupname = activitygrouprelation.groupname
>>> LEFT join users ON crmentity.smownerid= users.id
>>> WHERE
>>> to_tsvector(' en', for_fts( activity.subject)) @@ to_tsquery(' en',
>>> replace(' Dhaka University of Bangladesh:*', ' ',':* & '))
>>> ORDER BY crmentity.modifiedtime DESC LIMIT 100
>>>
>>>
>>> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>>>
>>> Limit (cost=1.46..1.47 rows=1 width=99) (actual time=0.824..0.824 rows=0
>>> loops=1)
>>>  -> Sort (cost=1.46..1.47 rows=1 width=99) (actual time=0.819..0.819
>>> rows=0
>>> loops=1)
>>>  Sort Key: crmentity.modifiedtime
>>>  Sort Method: quicksort Memory: 17kB
>>>  -> Nested Loop Left Join (cost=0.27..1.45 rows=1 width=99) (actual
>>> time=0.752..0.752 rows=0 loops=1)
>>>  -> Nested Loop Left Join (cost=0.27..1.17 rows=1 width=82) (actual
>>> time=0.750..0.750 rows=0 loops=1)
>>>  -> Nested Loop Left Join (cost=0.27..0.88 rows=1 width=79) (actual
>>> time=0.748..0.748 rows=0 loops=1)
>>>  -> Nested Loop (cost=0.27..0.60 rows=1 width=56) (actual
>>> time=0.746..0.746
>>> rows=0 loops=1)
>>>  -> Bitmap Heap Scan on activity (cost=0.27..0.30 rows=1 width=36) (actual
>>> time=0.744..0.744 rows=0 loops=1)
>>>  Recheck Cond: (to_tsvector('en'::regconfig,
>>> regexp_replace((subject)::text,
>>> '(&[^;]+;)|(<[^>]+>)|([\\s\\r\\n\\t]+)'::text, ' '::text,
>>> 'gs'::text)) @@ ''' Dhaka'':* & ''univers'':* &
>>> ''bangladesh'':*'::tsquery)
>>>  -> Bitmap Index Scan on ftx_en_activity_subject (cost=0.00..0.27 rows=1
>>> width=0) (actual time=0.740..0.740 rows=0 loops=1)
>>>  Index Cond: (to_tsvector('en'::regconfig, regexp_replace((subject)::text,
>>> '(&[^;]+;)|(<[^>]+>)|([\\s\\r\\n\\t]+)'::text, ' '::te
>>> xt, 'gs'::text)) @@ ''' Dhaka'':* & ''univers'':* &
>>> ''bangladesh'':*'::tsquery)
>>>  -> Index Scan using crmentity_pkey on crmentity (cost=0.00..0.29 rows=1
>>> width=24) (never executed)
>>>  Index Cond: (crmentity.crmid = activity.activityid)
>>>  Filter: (crmentity.deleted = 0)
>>>  -> Index Scan using activitygrouprelation_activityid_idx on
>>> activitygrouprelation (cost=0.00..0.27 rows=1 width=27) (never executed)
>>>  Index Cond: (activitygrouprelation.activityid = crmentity.crmid)
>>>  -> Index Scan using groups_groupname_idx on groups (cost=0.00..0.27
>>> rows=1
>>> width=26) (never executed)
>>>  Index Cond: ((groups.groupname)::text =
>>> (activitygrouprelation.groupname)::text)
>>>  -> Index Scan using users_pkey on users (cost=0.00..0.27 rows=1 width=25)
>>> (never executed)
>>>  Index Cond: (crmentity.smownerid = users.id)
>>> Total runtime: 1.188 ms
>>>
>>>
>>>
>>>
>>> explain
>>> SELECT crmentity.crmid, crmentity.setype, crmentity.modifiedtime,
>>> activity.subject,case when ( users.user_name not like '') then
>>> users.user_name else groups.groupname end as user_name,
>>> activity.date_start
>>> FROM crmentity INNER JOIN activity ON crmentity.crmid =
>>> activity.activityid
>>> and crmentity.deleted = 0
>>> LEFT JOIN activitygrouprelation ON activitygrouprelation.activityid =
>>> crmentity.crmid
>>> LEFT JOIN groups ON groups.groupname = activitygrouprelation.groupname
>>> LEFT join users ON crmentity.smownerid= users.id
>>> WHERE
>>> to_tsvector(' en', for_fts( crmentity.description)) @@ to_tsquery(' en',
>>> replace(' Dhaka University of Bangladesh:*', ' ',':* & '))
>>> ORDER BY crmentity.modifiedtime DESC LIMIT 100
>>>
>>>  QUERY PLAN
>>>
>>>
>>> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>>>
>>> Limit (cost=1.50..1.51 rows=1 width=99) (actual time=5.044..5.047 rows=1
>>> loops=1)
>>>  -> Sort (cost=1.50..1.51 rows=1 width=99) (actual time=5.041..5.042
>>> rows=1
>>> loops=1)
>>>  Sort Key: crmentity.modifiedtime
>>>  Sort Method: quicksort Memory: 17kB
>>>  -> Nested Loop Left Join (cost=0.27..1.49 rows=1 width=99) (actual
>>> time=4.998..5.012 rows=1 loops=1)
>>>  -> Nested Loop Left Join (cost=0.27..1.19 rows=1 width=82) (actual
>>> time=4.952..4.961 rows=1 loops=1)
>>>  -> Nested Loop Left Join (cost=0.27..0.90 rows=1 width=79) (actual
>>> time=4.949..4.956 rows=1 loops=1)
>>>  -> Nested Loop (cost=0.27..0.60 rows=1 width=56) (actual
>>> time=4.943..4.948
>>> rows=1 loops=1)
>>>  -> Bitmap Heap Scan on crmentity (cost=0.27..0.30 rows=1 width=24)
>>> (actual
>>> time=4.727..4.799 rows=3 loops=1)
>>>  Recheck Cond: (to_tsvector('en'::regconfig, regexp_replace(description,
>>> '(&[^;]+;)|(<[^>]+>)|([\\s\\r\\n\\t]+)'::text, ' '::text, 'gs'
>>> ::text)) @@ ''' Dhaka'':* & ''univers'':* & ''bangladesh'':*'::tsquery)
>>>  Filter: (deleted = 0)
>>>  -> Bitmap Index Scan on ftx_en_crmentity_description (cost=0.00..0.27
>>> rows=1 width=0) (actual time=4.687..4.687 rows=3 loops=1)
>>>  Index Cond: (to_tsvector('en'::regconfig, regexp_replace(description,
>>> '(&[^;]+;)|(<[^>]+>)|([\\s\\r\\n\\t]+)'::text, ' '::text,
>>> 'gs'::text)) @@ ''' Dhaka'':* & ''univers'':* &
>>> ''bangladesh'':*'::tsquery)
>>>  -> Index Scan using activity_pkey on activity (cost=0.00..0.29 rows=1
>>> width=36) (actual time=0.043..0.043 rows=0 loops=3)
>>>  Index Cond: (activity.activityid = crmentity.crmid)
>>>  -> Index Scan using activitygrouprelation_activityid_idx on
>>> activitygrouprelation (cost=0.00..0.29 rows=1 width=27) (actual
>>> time=0.003..0.003
>>> rows=0 loops=1)
>>>  Index Cond: (activitygrouprelation.activityid = crmentity.crmid)
>>>  -> Index Scan using groups_groupname_idx on groups (cost=0.00..0.27
>>> rows=1
>>> width=26) (actual time=0.001..0.001 rows=0 loops=1)
>>>  Index Cond: ((groups.groupname)::text =
>>> (activitygrouprelation.groupname)::text)
>>>  -> Index Scan using users_pkey on users (cost=0.00..0.29 rows=1 width=25)
>>> (actual time=0.033..0.035 rows=1 loops=1)
>>>  Index Cond: (crmentity.smownerid = users.id)
>>> Total runtime: 5.229 ms
>>> (22 rows)
>>>
>>>
>>>
>>> \d crmentity
>>>  Table "public.crmentity"
>>>  Column | Type | Modifiers
>>> --------------+-----------------------------+--------------------
>>> crmid | integer | not null
>>> smcreatorid | integer | not null default 0
>>> smownerid | integer | not null default 0
>>> modifiedby | integer | not null default 0
>>> setype | character varying(30) | not null
>>> description | text |
>>> createdtime | timestamp without time zone | not null
>>> modifiedtime | timestamp without time zone | not null
>>> viewedtime | timestamp without time zone |
>>> status | character varying(50) |
>>> version | integer | not null default 0
>>> presence | integer | default 1
>>> deleted | integer | not null default 0
>>> Indexes:
>>>  "crmentity_pkey" PRIMARY KEY, btree (crmid)
>>>  "crmentity_createdtime_idx" btree (createdtime)
>>>  "crmentity_modifiedby_idx" btree (modifiedby)
>>>  "crmentity_modifiedtime_idx" btree (modifiedtime)
>>>  "crmentity_smcreatorid_idx" btree (smcreatorid)
>>>  "crmentity_smownerid_idx" btree (smownerid)
>>>  "ftx_en_crmentity_description" gin (to_tsvector('vcrm_en'::regconfig,
>>> for_fts(description)))
>>>  "crmentity_deleted_idx" btree (deleted)
>>> Referenced by:
>>>  TABLE "service" CONSTRAINT "fk_1_service" FOREIGN KEY (serviceid)
>>> REFERENCES crmentity(crmid) ON DELETE CASCADE
>>>  TABLE "cc2crmentity" CONSTRAINT "fk_cc2crmentity_crmentity" FOREIGN KEY
>>> (crm_id) REFERENCES crmentity(crmid) ON UPDATE CASCADE ON DELETE CASCADE
>>>
>>>
>>> \d activity
>>>
>>>  Table "public.activity"
>>>  Column | Type | Modifiers
>>>
>>> ------------------+------------------------+-------------------------------------------
>>> activityid | integer | not null default 0
>>> subject | character varying(250) | not null
>>> semodule | character varying(20) |
>>> activitytype | character varying(200) | not null
>>> date_start | date | not null
>>> due_date | date |
>>> time_start | character varying(50) |
>>> time_end | character varying(50) |
>>> sendnotification | character varying(3) | not null default '0'::character
>>> varying
>>> duration_hours | character varying(2) |
>>> duration_minutes | character varying(200) |
>>> status | character varying(200) |
>>> eventstatus | character varying(200) |
>>> priority | character varying(200) |
>>> location | character varying(150) |
>>> notime | character varying(3) | not null default '0'::character varying
>>> visibility | character varying(50) | not null default 'all'::character
>>> varying
>>> recurringtype | character varying(200) |
>>> end_date | date |
>>> end_time | character varying(50) |
>>> Indexes:
>>>  "activity_pkey" PRIMARY KEY, btree (activityid)
>>>  "activity_activitytype_idx" btree (activitytype)
>>>  "activity_date_start_idx" btree (date_start)
>>>  "activity_due_date_idx" btree (due_date)
>>>  "activity_eventstatus_idx" btree (eventstatus)
>>>  "activity_status_idx" btree (status)
>>>  "activity_subject_idx" btree (subject)
>>>  "activity_time_start_idx" btree (time_start)
>>>  "ftx_en_activity_subject" gin (to_tsvector('vcrm_en'::regconfig,
>>> for_fts(subject::text)))
>>>
>>>
>>        Regards,
>>                Oleg
>> _____________________________________________________________
>> Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
>> Sternberg Astronomical Institute, Moscow University, Russia
>> Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
>> phone: +007(495)939-16-83, +007(495)939-23-83
>>
>

 	Regards,
 		Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83

In response to

pgsql-performance by date

Next:From: Pierre CDate: 2010-11-29 16:47:49
Subject: Re: SELECT INTO large FKyed table is slow
Previous:From: Tobias BroxDate: 2010-11-29 14:32:16
Subject: Re: Full Text index is not using during OR operation

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group