Question

I’m not sure if this is an SQL Server bug or my mistake but here is the situation:

QUERY 1

select PK FROM PI_INFORM  WHERE RECORD_DATE>DATEADD(hour,-48, GETDATE())

this takes less than 0.5 secs and returns 20,000 records

QUERY 2

SELECT PK FROM dbo.getInformFullTextPKs('"HELLO"')

this takes less than 1 secs and returns 500 records

PROBLEM
If we join those two queries with INTERSECT, takes more than 3 minutes. Execution plans shows everything is performed using INDEX SEEK.

SELECT * FROM PI_INFORM WITH (NOLOCK)
WHERE PK IN (

select PK FROM PI_INFORM  WHERE RECORD_DATE>DATEADD(hour,-48, GETDATE())

INTERSECT

SELECT PK FROM PI_INFORM WHERE PK IN (SELECT PK FROM dbo.getInformFullTextPKs('"HELLO"'))
)

Answer 1

the following query is equivalent and should run faster

SELECT * FROM PI_INFORM WITH (NOLOCK)
WHERE 
PK IN (SELECT PK FROM dbo.getInformFullTextPKs('"HELLO"')) AND 
 RECORD_DATE>DATEADD(hour,-48, GETDATE())