On 14.05.2013 12:23, Sameer Thakur wrote:
Hello,
I am trying to find predicate information for a given SQL query plan as
provided by Oracle using DBMS_XPLAN. I am looking at the EXPLAIN command
for getting this query plan information, with no luck so far.
Does the EXPLAIN command provide predicate information?
Sure. For example,
postgres=# explain select * from a where id = 123;
QUERY PLAN
---
Seq Scan on a (cost=0.00..40.00 rows=12 width=4)
Filter: (id = 123)
(2 rows)
The predicate is right there on the Filter line. Likewise for a join:
postgres=# explain select * from a, b where a.id = b.id;
QUERY PLAN
-
Hash Join (cost=64.00..134.00 rows=2400 width=8)
Hash Cond: (a.id = b.id)
- Seq Scan on a (cost=0.00..34.00 rows=2400 width=4)
- Hash (cost=34.00..34.00 rows=2400 width=4)
- Seq Scan on b (cost=0.00..34.00 rows=2400 width=4)
(5 rows)
The join predicate is on the Hash Cond line.
- Heikki
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