Thank you for your quick response Gilberto. Much appreciated.
I may very well follow your recommendation if I can determine if the current delete statement is not doing any work.
Here is the statement and an explain:
DELETE FROM contents USING contents AS c LEFT JOIN contents_social_posts csp ON csp.content_id = c.id LEFT JOIN social_posts sp ON sp.id = csp.social_post_id WHERE c.type = 'Content::Text::News' AND (csp.id IS NULL OR sp.id IS NULL);
QUERY PLAN
--------------------------------------------------------------------------------------------------------
Delete on contents (cost=1150608.37..2295927.20 rows=1 width=24)
-> Nested Loop (cost=1150608.37..2295927.20 rows=1 width=24)
-> Hash Right Join (cost=1150608.37..1173423.64 rows=1 width=18)
Hash Cond: (csp.content_id = c.id)
-> Hash Left Join (cost=6247.16..8286.32 rows=54372 width=24)
Hash Cond: (csp.social_post_id = sp.id)
-> Seq Scan on contents_social_posts csp (cost=0.00..951.72 rows=54372 width=18)
-> Hash (cost=4978.18..4978.18 rows=101518 width=10)
-> Seq Scan on social_posts sp (cost=0.00..4978.18 rows=101518 width=10)
-> Hash (cost=1075343.73..1075343.73 rows=3970439 width=10)
-> Seq Scan on contents c (cost=0.00..1075343.73 rows=3970439 width=10)
Filter: ((type)::text = 'Content::Text::News'::text)
-> Seq Scan on contents (cost=0.00..1059623.78 rows=6287978 width=6)
(14 rows)
As you can see, many sequential scans especially 2 on the table we are performing the delete on
Description of contents:
\d contents
Table "public.contents"
Column | Type | Modifiers
---------------+-----------------------------+-------------------------------------------------------
id | integer | not null default nextval('contents_id_seq'::regclass)
raw_content | text |
title | text |
description | text |
source_url | text |
published_at | timestamp without time zone |
guid | text |
type | character varying(255) |
created_at | timestamp without time zone |
updated_at | timestamp without time zone |
image_url | text |
original_id | character varying(255) |
refined_date | date |
thumbnail_url | text |
user_id | integer |
flagged_at | timestamp without time zone |
flagged_by | integer |
removed_at | timestamp without time zone |
removed_by | integer |
category_id | integer |
parent_id | integer |
parent_type | character varying(255) |
processing | boolean | default false
sharable_id | integer |
sharable_type | character varying(255) |
meta_data | text |
medium_url | text |
pinned_at | date |
pinned_until | date |
banner_url | text |
deleted_at | timestamp without time zone |
Indexes:
"primets_contents_pkey_id" PRIMARY KEY, btree (id), tablespace "prime2indexes"
"primets_content_parent" btree (parent_id, parent_type), tablespace "prime2indexes"
"primets_contents_category" btree (category_id), tablespace "prime2indexes"
"primets_contents_desc_gin" gin (to_tsvector('english'::regconfig, description)), tablespace "prime2indexes"
"primets_contents_guid" btree (guid), tablespace "prime2indexes"
"primets_contents_pin_priority" btree ((GREATEST(refined_date::timestamp without time zone, pinned_until + '1 day'::interval)), id), tablespace "prime2indexes"
"primets_contents_refined_date_id" btree (refined_date, id), tablespace "prime2indexes"
"primets_contents_sharable_id_sharable_type" btree (sharable_id, sharable_type), tablespace "prime2indexes"
"primets_contents_source_gin" gin (to_tsvector('english'::regconfig, source_url)), tablespace "prime2indexes"
"primets_contents_title_gin" gin (to_tsvector('english'::regconfig, title)), tablespace "prime2indexes"
"primets_contents_type" btree (type), tablespace "prime2indexes"
"primets_contents_user_id" btree (user_id), tablespace "prime2indexes"
Triggers:
_replication_logtrigger AFTER INSERT OR DELETE OR UPDATE ON contents FOR EACH ROW EXECUTE PROCEDURE _replication.logtrigger('_replication', '26', 'k')
_replication_truncatetrigger BEFORE TRUNCATE ON contents FOR EACH STATEMENT EXECUTE PROCEDURE _replication.log_truncate('26')
Disabled triggers:
_replication_denyaccess BEFORE INSERT OR DELETE OR UPDATE ON contents FOR EACH ROW EXECUTE PROCEDURE _replication.denyaccess('_replication')
_replication_truncatedeny BEFORE TRUNCATE ON contents FOR EACH STATEMENT EXECUTE PROCEDURE _replication.deny_truncate()
On Tue, Jun 28, 2016 at 1:15 PM, Gilberto Castillo <gilberto.castillo@xxxxxxxxx> wrote:
> Good morning,
>
> We have been running a delete for nearly 24 hours now. I would like to
> verify that it is either doing what it is supposed to do or 'spinning its
> wheels'.
>
> We are running postgres 9.2.12.
>
> The delete statement is not waiting on any other transaction.
>
> I have run straces on the pid and I see lots of 'reads, lseeks, and an
> occasional semop. I have also looked in the base directory at the file
> matched by the oid of the table (as defined in pg_class) and have seen no
> change in size.
>
> Is there somewhere else I can verify that work is / is not being done?
> Perhaps looking for something else in strace?
My recomendation,
El DELETE es prohibitivo en Cualquier gestor de BD para ello ponga a su
concideración dos formas de como mejorar su comportamiento en PostgreSQL
--Solución 1
DELETE FROM string s WHERE NOT EXISTS (SELECT 1 FROM data d WHERE
d.object_id = s.id OR d.property_id = s.id OR d.value_id = s.id);
--Solución 2
(1) CREATE TABLE copia AS SELECT (...) WHERE (...)
(2) TRUNCATE en la tabla original.
(3) INSERT (...) SELECT (...) --actualizar desde la copia la tabla original
(4) DROP TABLE copia.
>
> Thanks for your time.
>
> --
> *Mark Steben*
> Database Administrator
> @utoRevenue <http://www.autorevenue.com/> | Autobase
> <http://www.autobase.net/>
> CRM division of Dominion Dealer Solutions
> 95D Ashley Ave.
> West Springfield, MA 01089
> t: 413.327-3045
> f: 413.383-9567
>
> www.fb.com/DominionDealerSolutions
> www.twitter.com/DominionDealer
> www.drivedominion.com <http://www.autorevenue.com/>
>
> <http://autobasedigital.net/marketing/DD12_sig.jpg>
>
--
Saludos,
Gilberto Castillo
ETECSA, La Habana, Cuba
Mark Steben
Database Administrator
@utoRevenue | Autobase
CRM division of Dominion Dealer Solutions
95D Ashley Ave.
West Springfield, MA 01089
t: 413.327-3045
f: 413.383-9567
Database Administrator
@utoRevenue | Autobase
CRM division of Dominion Dealer Solutions
95D Ashley Ave.
West Springfield, MA 01089
t: 413.327-3045
f: 413.383-9567
www.fb.com/DominionDealerSolutions
www.twitter.com/DominionDealer
www.drivedominion.com
