optimization join on random value

From: Anton Bushmelev <djeday84(at)gmail(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: optimization join on random value
Date: 2015-05-03 21:23:28
Message-ID: CAK0X_okQKj8C9FO6LMOhMmhCdsaTTpB2aqa26TvWVFoA53-HhQ@mail.gmail.com
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Hello guru of postgres, it's possoble to tune query with join on random
string ?
i know that it is not real life example, but i need it for tests.

soe=# explain
soe-# SELECT ADDRESS_ID,
soe-# CUSTOMER_ID,
soe-# DATE_CREATED,
soe-# HOUSE_NO_OR_NAME,
soe-# STREET_NAME,
soe-# TOWN,
soe-# COUNTY,
soe-# COUNTRY,
soe-# POST_CODE,
soe-# ZIP_CODE
soe-# FROM ADDRESSES
soe-# WHERE customer_id = trunc( random()*45000) ;
QUERY
PLAN
-------------------------------------------------------------------------------------------
Seq Scan on addresses (cost=0.00..165714.00 rows=22500 width=84)
Filter: ((customer_id)::double precision = trunc((random() *
45000::double precision)))
(2 rows)

soe=# \d addresses;
soe=# \d addresses;
Table
"public.addresses"

Column | Type |
Modifiers

------------------+-----------------------------+-----------

address_id | bigint | not
null
customer_id | bigint | not
null
date_created | timestamp without time zone | not
null
house_no_or_name | character varying(60)
|

street_name | character varying(60)
|

town | character varying(60)
|

county | character varying(60)
|

country | character varying(60)
|

post_code | character varying(12)
|

zip_code | character varying(12)
|

Indexes:

"addresses_pkey" PRIMARY KEY, btree
(address_id)

"addresses_cust_ix" btree
(customer_id)

Foreign-key
constraints:

"add_cust_fk" FOREIGN KEY (customer_id) REFERENCES
customers(customer_id) DEFERRABLE

same query in oracle same query use index access path:

00:05:23 (1)c##bushmelev_aa(at)orcl> explain plan for
SELECT ADDRESS_ID,
CUSTOMER_ID,
DATE_CREATED,
HOUSE_NO_OR_NAME,
STREET_NAME,
TOWN,
COUNTY,
COUNTRY,
POST_CODE,
ZIP_CODE
FROM soe.ADDRESSES
* WHERE customer_id = dbms_random.value ();*

Explained.

Elapsed: 00:00:00.05
00:05:29 (1)c##bushmelev_aa(at)orcl> @utlxpls

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------
Plan hash value: 317664678

-----------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
Cost (%CPU)| Time |
-----------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 150 |
5 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| ADDRESSES | 2 | 150 |
5 (0)| 00:00:01 |
|* 2 | *INDEX RANGE SCAN * | ADDRESS_CUST_IX | 2 |
| 3 (0)| 00:00:01 |
-----------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("CUSTOMER_ID"="DBMS_RANDOM"."VALUE"())

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