PostgreSQL Reversed ILIKE on column name
0
I am trying to figure out the given username by frontend is a valid name or not.
I have a table that contains lot of names.
So for example I got Adam18 I need to give an answer in real time (< 500ms)
My query:
SELECT * FROM names WHERE 'Adam18' ILIKE '%' || name || '%'
The query is correct but it uses sequential scan
Explain result:
Seq Scan on names (cost=0.00..2341.20 rows=527 width=516) (actual time=1.452..24.774 rows=12 loops=1)
Filter: ('Adam18'::text ~~ (('%'::text || (name)::text) || '%'::text))
Rows Removed by Filter: 105314
Buffers: shared hit=498
Planning time: 0.062 ms
Execution time: 24.796 ms
Is there a way to create index on this case?
My current index:
CREATE INDEX names_gin_idx ON names USING gin (name gin_trgm_ops)
I cannot use this. Can you help me?
database postgresql indexing query-optimization sql-like
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
add a comment |
0
I am trying to figure out the given username by frontend is a valid name or not.
I have a table that contains lot of names.
So for example I got Adam18 I need to give an answer in real time (< 500ms)
My query:
SELECT * FROM names WHERE 'Adam18' ILIKE '%' || name || '%'
The query is correct but it uses sequential scan
Explain result:
Seq Scan on names (cost=0.00..2341.20 rows=527 width=516) (actual time=1.452..24.774 rows=12 loops=1)
Filter: ('Adam18'::text ~~ (('%'::text || (name)::text) || '%'::text))
Rows Removed by Filter: 105314
Buffers: shared hit=498
Planning time: 0.062 ms
Execution time: 24.796 ms
Is there a way to create index on this case?
My current index:
CREATE INDEX names_gin_idx ON names USING gin (name gin_trgm_ops)
I cannot use this. Can you help me?
database postgresql indexing query-optimization sql-like
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
Yes I did it, there are 105 326 rows in the table
– L.Farkas
Nov 22 '18 at 13:35
Those 24ms are already way below the required 500ms ;) But I think trigram indexes can only be used in the "other directory", e.g.where name ilike '%Adam18%'Full text search might be an alternative
– a_horse_with_no_name
Nov 22 '18 at 13:54
I guess its faster now than I tried first time, because of the cache. What kind of index do you suggest on ILike instead of full text search?
– L.Farkas
Nov 22 '18 at 14:02
As I said: I don't think you can support that condition with an index (only the "other way round")
– a_horse_with_no_name
Nov 22 '18 at 14:04
add a comment |
0
0
0
I am trying to figure out the given username by frontend is a valid name or not.
I have a table that contains lot of names.
So for example I got Adam18 I need to give an answer in real time (< 500ms)
My query:
SELECT * FROM names WHERE 'Adam18' ILIKE '%' || name || '%'
The query is correct but it uses sequential scan
Explain result:
Seq Scan on names (cost=0.00..2341.20 rows=527 width=516) (actual time=1.452..24.774 rows=12 loops=1)
Filter: ('Adam18'::text ~~ (('%'::text || (name)::text) || '%'::text))
Rows Removed by Filter: 105314
Buffers: shared hit=498
Planning time: 0.062 ms
Execution time: 24.796 ms
Is there a way to create index on this case?
My current index:
CREATE INDEX names_gin_idx ON names USING gin (name gin_trgm_ops)
I cannot use this. Can you help me?
database postgresql indexing query-optimization sql-like
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
I am trying to figure out the given username by frontend is a valid name or not.
I have a table that contains lot of names.
So for example I got Adam18 I need to give an answer in real time (< 500ms)
My query:
SELECT * FROM names WHERE 'Adam18' ILIKE '%' || name || '%'
The query is correct but it uses sequential scan
Explain result:
Seq Scan on names (cost=0.00..2341.20 rows=527 width=516) (actual time=1.452..24.774 rows=12 loops=1)
Filter: ('Adam18'::text ~~ (('%'::text || (name)::text) || '%'::text))
Rows Removed by Filter: 105314
Buffers: shared hit=498
Planning time: 0.062 ms
Execution time: 24.796 ms
Is there a way to create index on this case?
My current index:
CREATE INDEX names_gin_idx ON names USING gin (name gin_trgm_ops)
I cannot use this. Can you help me?
database postgresql indexing query-optimization sql-like
database postgresql indexing query-optimization sql-like
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
edited Nov 22 '18 at 13:34
L.Farkas
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
asked Nov 22 '18 at 13:28
L.FarkasL.Farkas
84
84
Yes I did it, there are 105 326 rows in the table
– L.Farkas
Nov 22 '18 at 13:35
Those 24ms are already way below the required 500ms ;) But I think trigram indexes can only be used in the "other directory", e.g.where name ilike '%Adam18%'Full text search might be an alternative
– a_horse_with_no_name
Nov 22 '18 at 13:54
I guess its faster now than I tried first time, because of the cache. What kind of index do you suggest on ILike instead of full text search?
– L.Farkas
Nov 22 '18 at 14:02
As I said: I don't think you can support that condition with an index (only the "other way round")
– a_horse_with_no_name
Nov 22 '18 at 14:04
add a comment |
Yes I did it, there are 105 326 rows in the table
– L.Farkas
Nov 22 '18 at 13:35
Those 24ms are already way below the required 500ms ;) But I think trigram indexes can only be used in the "other directory", e.g.where name ilike '%Adam18%'Full text search might be an alternative
– a_horse_with_no_name
Nov 22 '18 at 13:54
I guess its faster now than I tried first time, because of the cache. What kind of index do you suggest on ILike instead of full text search?
– L.Farkas
Nov 22 '18 at 14:02
As I said: I don't think you can support that condition with an index (only the "other way round")
– a_horse_with_no_name
Nov 22 '18 at 14:04
Yes I did it, there are 105 326 rows in the table
– L.Farkas
Nov 22 '18 at 13:35
Yes I did it, there are 105 326 rows in the table
– L.Farkas
Nov 22 '18 at 13:35
Those 24ms are already way below the required 500ms ;) But I think trigram indexes can only be used in the "other directory", e.g.
where name ilike '%Adam18%' Full text search might be an alternative– a_horse_with_no_name
Nov 22 '18 at 13:54
Those 24ms are already way below the required 500ms ;) But I think trigram indexes can only be used in the "other directory", e.g.
where name ilike '%Adam18%' Full text search might be an alternative– a_horse_with_no_name
Nov 22 '18 at 13:54
I guess its faster now than I tried first time, because of the cache. What kind of index do you suggest on ILike instead of full text search?
– L.Farkas
Nov 22 '18 at 14:02
I guess its faster now than I tried first time, because of the cache. What kind of index do you suggest on ILike instead of full text search?
– L.Farkas
Nov 22 '18 at 14:02
As I said: I don't think you can support that condition with an index (only the "other way round")
– a_horse_with_no_name
Nov 22 '18 at 14:04
As I said: I don't think you can support that condition with an index (only the "other way round")
– a_horse_with_no_name
Nov 22 '18 at 14:04
add a comment |
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Yes I did it, there are 105 326 rows in the table
– L.Farkas
Nov 22 '18 at 13:35
Those 24ms are already way below the required 500ms ;) But I think trigram indexes can only be used in the "other directory", e.g.
where name ilike '%Adam18%'Full text search might be an alternative– a_horse_with_no_name
Nov 22 '18 at 13:54
I guess its faster now than I tried first time, because of the cache. What kind of index do you suggest on ILike instead of full text search?
– L.Farkas
Nov 22 '18 at 14:02
As I said: I don't think you can support that condition with an index (only the "other way round")
– a_horse_with_no_name
Nov 22 '18 at 14:04