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Some information about the tables involved in the query:
1) There two tables named as “small” and “big”
2) The table “small” has 1000 rows in it
3) The table “big” has 20 million rows
4) Join columns are “Id1” and “Id2”
5) Both tables have unique non-clustered indexes on these two join columns

Index on (Id1 + Id2)

Without the abstract plan clause “plan” optimizer uses nested-loop-join.
My goal is to use HASH join instead of Nested-Loop-Join.

So I use abstract plan in the query like below:

update big
set Amount= 100.00
from small s,big b
where s.Id1 = b.Id1
and s.Id2 = b.Id2
plan “(h_join (sort (t_scan s)) (sort (t_scan b)))”

I am getting message below and optimizer is using nested-Loop_join (please see the query – plan below)

Abstract Plan (AP) Warning : An error occured while applying the AP:
( h_join ( sort ( t_scan s ) ) ( sort ( t_scan b ) ) )
to the SQL query:
update big set Amount= 100.00 from small s,big b where s.Id1 = b.Id1 and s.Id2 = b.Id2
Failed to apply the top operator ‘h_join ‘ of the following AP fragment:
( h_join ( sort ( t_scan s ) ) ( sort ( t_scan b ) ) )
The children of the ‘h_join ‘ operator don’t have t:q!he required properties, as ordering, partitioning.
The logical relational operation is valid at this point but it can not be implemented by this physical operator.
The AP property enforcer operators ‘sort’, ‘xchg’ or ‘enforce’ can be used to create the needed physical properties.
When an ordering is missing, the nl_join or h_join peer physical operators that don’t need an ordering can be used.
The following template can be used as a basis for a valid AP:
( also_enforce ( update ( also_enforce ( join ( also_enforce ( scan ( table ( b big ) ) ) ) ( also_enforce ( scan ( table ( s small ) ) ) ) ) ) ) )
The optimizer will try to complete the compilation of this query; on success, the query will be executed normally.

QUERY PLAN FOR STATEMENT 1 (at line 9).
Optimized using Serial Mode
Optimized using the Abstract Plan in the PLAN clause.

STEP 1
The type of query is UPDATE.

5 operator(s) under root

|ROOT:EMIT Operator (VA = 5)
|
| |UPDATE Operator (VA = 4)
| | The update mode is direct.
| |
| | |NESTED LOOP JOIN Operator (VA = 3) (Join Type: Left Semi Join)
| | |
| | | |SORT Operator (VA = 1)
| | | | Using Worktable1 for internal storage.
| | | |
| | | | |SCAN Operator (VA = 0)
| | | | | FROM TABLE
| | | | | big
| | | | | b
| | | | | Table Scan.
| | | | | Forward Scan.
| | | | | Positioning at start of table.
| | | | | Using I/O Size 4 Kbytes for data pages.
| | | | | With LRU Buffer Replacement Strategy for data pages.
| | |
| | | |SCAN Operator (VA = 2)
| | | | FROM TABLE
| | | | small
| | | | s
| | | | Table Scan.
| | | | Forward Scan.
| | | | Positioning at start of table.
| | | | Using I/O Size 4 Kbytes for data pages.
| | | | With LRU Buffer Replacement Strategy for data pages.
| |
| | TO TABLE
| | big
| | Using I/O Size 4 Kbytes for data pages.

Thanks

Will appreciate if u send your ques on mail. as this is comment section for interview questions. Thnx.

I have a doubt in tempdb bindings.

As per my understanding “binding a particular login to a specifice database” is all the activities carried out for example sorting, calculating agregates etc…. will be done in the binded temporary database for that particular login.

Am i correct? if wrong please suggest.

Regards,
Vinz

It worked successfully for one server. if we want to set for multiple servers how to set it.

I tried it but dint get the result. Please help me.

Regards,
Vinz