Hello all,
We recently moved our production database systems from a 9.4 running on a
self-managed EC2 instance to 9.6.10 on Amazon’s AWS (same RAM, CPU). After the
move, we’re finding that certain queries that we run against a GIN full-text
index have some occasionally very slow executions and I’m struggling to figure
out what to do about it. I would be very grateful for any ideas!
Thanks,
Scott
The setup we have is a 32-core, 244 GB RAM primary with a same-sized read
replica. The queries are running off the replica, but performance is roughly
the same between the master and the replica.
Here’s a query that’s performing badly:
SELECT ls.location AS locationId FROM location_search ls WHERE ls.client = 83
AND search_field_tsvector @@ to_tsquery('9000:* &Smith''s:* &Mill:*') AND
ls.favorite = TRUE LIMIT 1
The mean time for this query (and others like it) is about 900ms, but the std
deviation is over 1000ms and the max is 11000ms.
The explain looks like this:
Limit (cost=1516.25..1520.52 rows=1 width=223) (actual time=4506.482..4506.482
rows=0 loops=1)
Buffers: shared hit=9073
-> Bitmap Heap Scan on location_search ls (cost=1516.25..1520.52 rows=1
width=223) (actual time=4506.480..4506.480 rows=0 loops=1)
Recheck Cond: (search_field_tsvector @@ to_tsquery('9000:* &Smith''s:*
&Mill:*'::text))
Filter: (favorite AND (client = 83))
Rows Removed by Filter: 8
Heap Blocks: exact=12
Buffers: shared hit=9073
-> Bitmap Index Scan on location_search_tsvector_idx
(cost=0.00..1516.25 rows=1 width=0) (actual time=4506.450..4506.450 rows=12
loops=1)
Index Cond: (search_field_tsvector @@ to_tsquery('9000:*
&Smith''s:* &Mill:*'::text))
Buffers: shared hit=9061
Planning time: 0.240 ms
Execution time: 4509.995 ms
The table has about 30 million rows in it. The table and index definition are:
CREATE TABLE public.location_search
(
id bigint NOT NULL DEFAULT nextval('location_search_id_seq'::regclass),
person_location bigint,
person bigint,
client_location bigint,
client bigint,
location bigint,
org_unit_id bigint,
latitude numeric(10,7),
longitude numeric(10,7),
geofence numeric(10,7),
address_line_one text COLLATE pg_catalog."default",
address_line_two text COLLATE pg_catalog."default",
city text COLLATE pg_catalog."default",
state text COLLATE pg_catalog."default",
postal_code text COLLATE pg_catalog."default",
country text COLLATE pg_catalog."default",
full_address text COLLATE pg_catalog."default",
is_google_verified boolean,
address_source text COLLATE pg_catalog."default",
active boolean,
name character varying(255) COLLATE pg_catalog."default",
external_client_location_id character varying(500) COLLATE
pg_catalog."default",
custom_field_values hstore,
location_tags hstore,
legacy_location_id bigint,
favorite boolean,
search_field_tsvector tsvector
)
WITH (
OIDS = FALSE
)
TABLESPACE pg_default;
CREATE INDEX location_search_tsvector_idx
ON public.location_search USING gin
(search_field_tsvector)
TABLESPACE pg_default;
Right now the output of pgstatginindex is this:
version pending_pages pending_tuples
2 214 9983
Lastly, here are some of the relevant config entries:
autovacuum on
autovacuum_analyze_scale_factor 0
autovacuum_analyze_threshold 50
autovacuum_freeze_max_age 400000000
autovacuum_max_workers 3
autovacuum_multixact_freeze_max_age 400000000
autovacuum_naptime 30s
autovacuum_vacuum_cost_delay 20ms
autovacuum_vacuum_cost_limit -1
autovacuum_vacuum_scale_factor 0
autovacuum_vacuum_threshold 50
cpu_index_tuple_cost 0
cpu_operator_cost 0
cpu_tuple_cost 0
cursor_tuple_fraction 0
effective_cache_size 125777784kB
effective_io_concurrency 1
gin_fuzzy_search_limit 0
gin_pending_list_limit 4MB
maintenance_work_mem 4027MB
seq_page_cost 1
shared_buffers 62888888kB
work_mem 200000kB
SCOTT RANKIN
VP, Technology
Motus, LLC
Two Financial Center, 60 South Street, Boston, MA 02111
617.467.1900 (O) | sran...@motus.com<mailto:rcaraf...@motus.com>
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