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Posted to user@hive.apache.org by bharath vissapragada <bh...@gmail.com> on 2010/12/23 13:24:21 UTC
mergeJoinTree ??
Hi all,
Once the JoinTrees are created by the the semantic analyzer for a
query block , a function mergeJoinTree(qb) is called .
Can anyone tell me what it does ?
Thanks in anticipation,
Bharath.V
Re: mergeJoinTree ??
Posted by bharath vissapragada <bh...@students.iiit.ac.in>.
Thanks for the help namit !
:)
On Fri, Dec 24, 2010 at 12:00 PM, Namit Jain <nj...@fb.com> wrote:
> Yes
>
> Sent from my iPhone
>
> On Dec 23, 2010, at 8:02 PM, "bharath vissapragada" <bharathvissapragada1990@gmail.com
> > wrote:
>
>> Hi,
>>
>> Thanks for the reply .
>>
>> This is the optimization of converting 2 MR jobs to a single MR job
>> right ? as we are using only a single join val per table.
>>
>> Thanks
>> Bharath.V
>> 4th year undergraduate,
>> IIIT Hyderabad,
>>
>> On Fri, Dec 24, 2010 at 12:22 AM, Namit Jain <nj...@fb.com> wrote:
>>> The idea there is to merge the join trees.
>>>
>>> For eg. If the query is:
>>>
>>> Select * from
>>> T1 join T2 on T1.key = T2.key
>>> join T3 on T1.key = T3.key
>>> Where ...
>>>
>>>
>>> One join can have 3 inputs: T1, T2 and T3.
>>>
>>> mergeJoinTree() merges the 2 join operators (T1,T2) and (result of
>>> (T1,T2), T3)
>>> into a new join operator with 3 children (T1,T2,T3)
>>>
>>>
>>> On 12/23/10 4:24 AM, "bharath vissapragada"
>>> <bh...@gmail.com> wrote:
>>>
>>>> Hi all,
>>>>
>>>>
>>>> Once the JoinTrees are created by the the semantic analyzer for a
>>>> query block , a function mergeJoinTree(qb) is called .
>>>> Can anyone tell me what it does ?
>>>>
>>>> Thanks in anticipation,
>>>> Bharath.V
>>>
>>>
>
Re: mergeJoinTree ??
Posted by Namit Jain <nj...@fb.com>.
Yes
Sent from my iPhone
On Dec 23, 2010, at 8:02 PM, "bharath vissapragada" <bharathvissapragada1990@gmail.com
> wrote:
> Hi,
>
> Thanks for the reply .
>
> This is the optimization of converting 2 MR jobs to a single MR job
> right ? as we are using only a single join val per table.
>
> Thanks
> Bharath.V
> 4th year undergraduate,
> IIIT Hyderabad,
>
> On Fri, Dec 24, 2010 at 12:22 AM, Namit Jain <nj...@fb.com> wrote:
>> The idea there is to merge the join trees.
>>
>> For eg. If the query is:
>>
>> Select * from
>> T1 join T2 on T1.key = T2.key
>> join T3 on T1.key = T3.key
>> Where ...
>>
>>
>> One join can have 3 inputs: T1, T2 and T3.
>>
>> mergeJoinTree() merges the 2 join operators (T1,T2) and (result of
>> (T1,T2), T3)
>> into a new join operator with 3 children (T1,T2,T3)
>>
>>
>> On 12/23/10 4:24 AM, "bharath vissapragada"
>> <bh...@gmail.com> wrote:
>>
>>> Hi all,
>>>
>>>
>>> Once the JoinTrees are created by the the semantic analyzer for a
>>> query block , a function mergeJoinTree(qb) is called .
>>> Can anyone tell me what it does ?
>>>
>>> Thanks in anticipation,
>>> Bharath.V
>>
>>
Re: mergeJoinTree ??
Posted by bharath vissapragada <bh...@gmail.com>.
Hi,
Thanks for the reply .
This is the optimization of converting 2 MR jobs to a single MR job
right ? as we are using only a single join val per table.
Thanks
Bharath.V
4th year undergraduate,
IIIT Hyderabad,
On Fri, Dec 24, 2010 at 12:22 AM, Namit Jain <nj...@fb.com> wrote:
> The idea there is to merge the join trees.
>
> For eg. If the query is:
>
> Select * from
> T1 join T2 on T1.key = T2.key
> join T3 on T1.key = T3.key
> Where ...
>
>
> One join can have 3 inputs: T1, T2 and T3.
>
> mergeJoinTree() merges the 2 join operators (T1,T2) and (result of
> (T1,T2), T3)
> into a new join operator with 3 children (T1,T2,T3)
>
>
> On 12/23/10 4:24 AM, "bharath vissapragada"
> <bh...@gmail.com> wrote:
>
>>Hi all,
>>
>>
>>Once the JoinTrees are created by the the semantic analyzer for a
>>query block , a function mergeJoinTree(qb) is called .
>>Can anyone tell me what it does ?
>>
>>Thanks in anticipation,
>>Bharath.V
>
>
Re: mergeJoinTree ??
Posted by Namit Jain <nj...@fb.com>.
The idea there is to merge the join trees.
For eg. If the query is:
Select * from
T1 join T2 on T1.key = T2.key
join T3 on T1.key = T3.key
Where ...
One join can have 3 inputs: T1, T2 and T3.
mergeJoinTree() merges the 2 join operators (T1,T2) and (result of
(T1,T2), T3)
into a new join operator with 3 children (T1,T2,T3)
On 12/23/10 4:24 AM, "bharath vissapragada"
<bh...@gmail.com> wrote:
>Hi all,
>
>
>Once the JoinTrees are created by the the semantic analyzer for a
>query block , a function mergeJoinTree(qb) is called .
>Can anyone tell me what it does ?
>
>Thanks in anticipation,
>Bharath.V