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Posted to user@pig.apache.org by Eric Tschetter <ec...@gmail.com> on 2010/03/26 18:55:41 UTC
MULTI_LEAF_MAP and DID_NOT_FIND_LOAD_ONLY_MAP_PLAN
I'm writing a fairly involved pig script to do some data munging and
after all was said and done, I end up getting the warnings mentioned
in the subject.
The grunt output is actually:
2010-03-26 09:42:33,245 [main] WARN
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
- Encountered Warning DID_NOT_FIND_LOAD_ONLY_MAP_PLAN 2 time(s).
2010-03-26 09:42:33,250 [main] WARN
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
- Encountered Warning MULTI_LEAF_MAP 1 time(s).
This is on pig 0.6.0. I tried to find a document that can explain
what these mean, but St. Google wasn't of much help. So, I looked at
the code to try and decipher what they would mean and from what I can
tell
"DID_NOT_FIND_LOAD_ONLY_MAP_PLAN" means that there is a map plan that
meets one of the following conditions
1) has no leaf
2) has more than one leaf
3) has no root
4) has more than one root
5) the leaf is not equivalent to the root
"MULTI_LEAF_MAP" apparently means that there are either zero or >=2
leaves on a map plan.
So, I'm guessing that the DID_NOT_FIND_LOAD_ONLY_MAP_PLAN warnings are
coming from having 2 leaves. Unfortunately, I have no clue what that
means. Can anyone shed some light on what these warnings mean, if I
need to care about them and what I should look for to get rid of them
(if they are, in fact, not good)?
Also, if the meaning of these warnings is documented somewhere and
Google just couldn't find it, please point me to the documentation.
--Eric Tschetter
Re: MULTI_LEAF_MAP and DID_NOT_FIND_LOAD_ONLY_MAP_PLAN
Posted by Eric Tschetter <ec...@gmail.com>.
This happens in both pig 0.6.1 (built off the branch) and pig 0.6.0.
I built trunk (0.8.1) and tried it, but our internal loader functions
extend ReversibleLoadStoreFunc which apparently doesn't exist in trunk
any more. I'm not sure what it will take to update our loader and,
unfortunately, don't have the time to look into updating it right now.
So, I'll have to sit on this for a bit.
--Eric
On Wed, Apr 7, 2010 at 10:16 PM, Ashutosh Chauhan
<as...@gmail.com> wrote:
> Also, which pig version are you seeing this happening ? Is it possible
> for you to try your script on trunk and see if you still get the
> warnings.
>
> Ashutosh
>
> On Wed, Apr 7, 2010 at 18:41, Eric Tschetter <ec...@gmail.com> wrote:
>> Ok, I'll try to get one. I'm not sure what exact part of the script
>> is doing it so it might take some time. In my wanderings around the
>> interwebs trying to figure out what the warnings meant, however, there
>> was someone else who posted to this (I think) list with a script that
>> produced the warnings:
>>
>> http://www.search-hadoop.com/m?id=974ba0d80912142112v4682f6afp890496d57be2bc00@mail.gmail.com||
>>
>> It looks like I'm doing something similar to him. I'll try to see if
>> I can figure out what part of my script is causing it to happen and
>> then just make up something that also causes it though.
>>
>> --Eric
>>
>>
>> On Wed, Apr 7, 2010 at 4:27 PM, Ashutosh Chauhan
>> <as...@gmail.com> wrote:
>>> Hi Eric,
>>>
>>> What you wrote is mostly true. A distilled down script generating same
>>> warnings will be helpful. Thing is it seems that invariants which
>>> should always hold (in theory) on generated map-reduce plan from query
>>> are getting violated. I would like to see the script which can make
>>> this happen. This might be a bug.
>>>
>>> Ashutosh
>>>
>>> On Wed, Mar 31, 2010 at 13:36, Eric Tschetter <ec...@gmail.com> wrote:
>>>> Ok, so if I'm understanding you correctly, the warnings are basically
>>>> Pig saying that it cannot apply a specific optimization, is that
>>>> correct? If so, then might I make a suggestion that they not show up
>>>> as "WARNING" but as "INFO" or something. Also, a slightly more
>>>> meaningful message (something like, "Optimization XX was not able to
>>>> be applied because of YY") might be helpful. It also sounds like I
>>>> can safely ignore them as they won't affect the meaning of the pig
>>>> script, just how it is actually executed.
>>>>
>>>> If this is wrong, I can try to distill down the script and get the
>>>> same warnings.
>>>>
>>>> --Eric
>>>>
>>>>
>>>>
>>>> On Tue, Mar 30, 2010 at 10:37 PM, Ashutosh Chauhan
>>>> <as...@gmail.com> wrote:
>>>>> After Pig compiles a query into a series of map-reduce plans, it once
>>>>> again iterate through those jobs trying to spot the opportunities of
>>>>> further optimizations. While visiting such compiled plan, there are
>>>>> certain invariants which must always hold. If Pig finds contrary to
>>>>> it, it backs out and doesn't try to apply that optimization step. It
>>>>> seems that you are running into that situation.
>>>>> How this affects computation of your query I am not sure. Can you
>>>>> paste stripped down version of your query which generates these
>>>>> warning messages?
>>>>>
>>>>> Ashutosh
>>>>>
>>>>> On Fri, Mar 26, 2010 at 10:55, Eric Tschetter <ec...@gmail.com> wrote:
>>>>>> I'm writing a fairly involved pig script to do some data munging and
>>>>>> after all was said and done, I end up getting the warnings mentioned
>>>>>> in the subject.
>>>>>>
>>>>>> The grunt output is actually:
>>>>>>
>>>>>> 2010-03-26 09:42:33,245 [main] WARN
>>>>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>>>>> - Encountered Warning DID_NOT_FIND_LOAD_ONLY_MAP_PLAN 2 time(s).
>>>>>> 2010-03-26 09:42:33,250 [main] WARN
>>>>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>>>>> - Encountered Warning MULTI_LEAF_MAP 1 time(s).
>>>>>>
>>>>>> This is on pig 0.6.0. I tried to find a document that can explain
>>>>>> what these mean, but St. Google wasn't of much help. So, I looked at
>>>>>> the code to try and decipher what they would mean and from what I can
>>>>>> tell
>>>>>>
>>>>>> "DID_NOT_FIND_LOAD_ONLY_MAP_PLAN" means that there is a map plan that
>>>>>> meets one of the following conditions
>>>>>>
>>>>>> 1) has no leaf
>>>>>> 2) has more than one leaf
>>>>>> 3) has no root
>>>>>> 4) has more than one root
>>>>>> 5) the leaf is not equivalent to the root
>>>>>>
>>>>>> "MULTI_LEAF_MAP" apparently means that there are either zero or >=2
>>>>>> leaves on a map plan.
>>>>>>
>>>>>> So, I'm guessing that the DID_NOT_FIND_LOAD_ONLY_MAP_PLAN warnings are
>>>>>> coming from having 2 leaves. Unfortunately, I have no clue what that
>>>>>> means. Can anyone shed some light on what these warnings mean, if I
>>>>>> need to care about them and what I should look for to get rid of them
>>>>>> (if they are, in fact, not good)?
>>>>>>
>>>>>> Also, if the meaning of these warnings is documented somewhere and
>>>>>> Google just couldn't find it, please point me to the documentation.
>>>>>>
>>>>>> --Eric Tschetter
>>>>>>
>>>>>
>>>>
>>>
>>
>
Re: MULTI_LEAF_MAP and DID_NOT_FIND_LOAD_ONLY_MAP_PLAN
Posted by Ashutosh Chauhan <as...@gmail.com>.
Also, which pig version are you seeing this happening ? Is it possible
for you to try your script on trunk and see if you still get the
warnings.
Ashutosh
On Wed, Apr 7, 2010 at 18:41, Eric Tschetter <ec...@gmail.com> wrote:
> Ok, I'll try to get one. I'm not sure what exact part of the script
> is doing it so it might take some time. In my wanderings around the
> interwebs trying to figure out what the warnings meant, however, there
> was someone else who posted to this (I think) list with a script that
> produced the warnings:
>
> http://www.search-hadoop.com/m?id=974ba0d80912142112v4682f6afp890496d57be2bc00@mail.gmail.com||
>
> It looks like I'm doing something similar to him. I'll try to see if
> I can figure out what part of my script is causing it to happen and
> then just make up something that also causes it though.
>
> --Eric
>
>
> On Wed, Apr 7, 2010 at 4:27 PM, Ashutosh Chauhan
> <as...@gmail.com> wrote:
>> Hi Eric,
>>
>> What you wrote is mostly true. A distilled down script generating same
>> warnings will be helpful. Thing is it seems that invariants which
>> should always hold (in theory) on generated map-reduce plan from query
>> are getting violated. I would like to see the script which can make
>> this happen. This might be a bug.
>>
>> Ashutosh
>>
>> On Wed, Mar 31, 2010 at 13:36, Eric Tschetter <ec...@gmail.com> wrote:
>>> Ok, so if I'm understanding you correctly, the warnings are basically
>>> Pig saying that it cannot apply a specific optimization, is that
>>> correct? If so, then might I make a suggestion that they not show up
>>> as "WARNING" but as "INFO" or something. Also, a slightly more
>>> meaningful message (something like, "Optimization XX was not able to
>>> be applied because of YY") might be helpful. It also sounds like I
>>> can safely ignore them as they won't affect the meaning of the pig
>>> script, just how it is actually executed.
>>>
>>> If this is wrong, I can try to distill down the script and get the
>>> same warnings.
>>>
>>> --Eric
>>>
>>>
>>>
>>> On Tue, Mar 30, 2010 at 10:37 PM, Ashutosh Chauhan
>>> <as...@gmail.com> wrote:
>>>> After Pig compiles a query into a series of map-reduce plans, it once
>>>> again iterate through those jobs trying to spot the opportunities of
>>>> further optimizations. While visiting such compiled plan, there are
>>>> certain invariants which must always hold. If Pig finds contrary to
>>>> it, it backs out and doesn't try to apply that optimization step. It
>>>> seems that you are running into that situation.
>>>> How this affects computation of your query I am not sure. Can you
>>>> paste stripped down version of your query which generates these
>>>> warning messages?
>>>>
>>>> Ashutosh
>>>>
>>>> On Fri, Mar 26, 2010 at 10:55, Eric Tschetter <ec...@gmail.com> wrote:
>>>>> I'm writing a fairly involved pig script to do some data munging and
>>>>> after all was said and done, I end up getting the warnings mentioned
>>>>> in the subject.
>>>>>
>>>>> The grunt output is actually:
>>>>>
>>>>> 2010-03-26 09:42:33,245 [main] WARN
>>>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>>>> - Encountered Warning DID_NOT_FIND_LOAD_ONLY_MAP_PLAN 2 time(s).
>>>>> 2010-03-26 09:42:33,250 [main] WARN
>>>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>>>> - Encountered Warning MULTI_LEAF_MAP 1 time(s).
>>>>>
>>>>> This is on pig 0.6.0. I tried to find a document that can explain
>>>>> what these mean, but St. Google wasn't of much help. So, I looked at
>>>>> the code to try and decipher what they would mean and from what I can
>>>>> tell
>>>>>
>>>>> "DID_NOT_FIND_LOAD_ONLY_MAP_PLAN" means that there is a map plan that
>>>>> meets one of the following conditions
>>>>>
>>>>> 1) has no leaf
>>>>> 2) has more than one leaf
>>>>> 3) has no root
>>>>> 4) has more than one root
>>>>> 5) the leaf is not equivalent to the root
>>>>>
>>>>> "MULTI_LEAF_MAP" apparently means that there are either zero or >=2
>>>>> leaves on a map plan.
>>>>>
>>>>> So, I'm guessing that the DID_NOT_FIND_LOAD_ONLY_MAP_PLAN warnings are
>>>>> coming from having 2 leaves. Unfortunately, I have no clue what that
>>>>> means. Can anyone shed some light on what these warnings mean, if I
>>>>> need to care about them and what I should look for to get rid of them
>>>>> (if they are, in fact, not good)?
>>>>>
>>>>> Also, if the meaning of these warnings is documented somewhere and
>>>>> Google just couldn't find it, please point me to the documentation.
>>>>>
>>>>> --Eric Tschetter
>>>>>
>>>>
>>>
>>
>
Re: MULTI_LEAF_MAP and DID_NOT_FIND_LOAD_ONLY_MAP_PLAN
Posted by Eric Tschetter <ec...@gmail.com>.
Ok, I'll try to get one. I'm not sure what exact part of the script
is doing it so it might take some time. In my wanderings around the
interwebs trying to figure out what the warnings meant, however, there
was someone else who posted to this (I think) list with a script that
produced the warnings:
http://www.search-hadoop.com/m?id=974ba0d80912142112v4682f6afp890496d57be2bc00@mail.gmail.com||
It looks like I'm doing something similar to him. I'll try to see if
I can figure out what part of my script is causing it to happen and
then just make up something that also causes it though.
--Eric
On Wed, Apr 7, 2010 at 4:27 PM, Ashutosh Chauhan
<as...@gmail.com> wrote:
> Hi Eric,
>
> What you wrote is mostly true. A distilled down script generating same
> warnings will be helpful. Thing is it seems that invariants which
> should always hold (in theory) on generated map-reduce plan from query
> are getting violated. I would like to see the script which can make
> this happen. This might be a bug.
>
> Ashutosh
>
> On Wed, Mar 31, 2010 at 13:36, Eric Tschetter <ec...@gmail.com> wrote:
>> Ok, so if I'm understanding you correctly, the warnings are basically
>> Pig saying that it cannot apply a specific optimization, is that
>> correct? If so, then might I make a suggestion that they not show up
>> as "WARNING" but as "INFO" or something. Also, a slightly more
>> meaningful message (something like, "Optimization XX was not able to
>> be applied because of YY") might be helpful. It also sounds like I
>> can safely ignore them as they won't affect the meaning of the pig
>> script, just how it is actually executed.
>>
>> If this is wrong, I can try to distill down the script and get the
>> same warnings.
>>
>> --Eric
>>
>>
>>
>> On Tue, Mar 30, 2010 at 10:37 PM, Ashutosh Chauhan
>> <as...@gmail.com> wrote:
>>> After Pig compiles a query into a series of map-reduce plans, it once
>>> again iterate through those jobs trying to spot the opportunities of
>>> further optimizations. While visiting such compiled plan, there are
>>> certain invariants which must always hold. If Pig finds contrary to
>>> it, it backs out and doesn't try to apply that optimization step. It
>>> seems that you are running into that situation.
>>> How this affects computation of your query I am not sure. Can you
>>> paste stripped down version of your query which generates these
>>> warning messages?
>>>
>>> Ashutosh
>>>
>>> On Fri, Mar 26, 2010 at 10:55, Eric Tschetter <ec...@gmail.com> wrote:
>>>> I'm writing a fairly involved pig script to do some data munging and
>>>> after all was said and done, I end up getting the warnings mentioned
>>>> in the subject.
>>>>
>>>> The grunt output is actually:
>>>>
>>>> 2010-03-26 09:42:33,245 [main] WARN
>>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>>> - Encountered Warning DID_NOT_FIND_LOAD_ONLY_MAP_PLAN 2 time(s).
>>>> 2010-03-26 09:42:33,250 [main] WARN
>>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>>> - Encountered Warning MULTI_LEAF_MAP 1 time(s).
>>>>
>>>> This is on pig 0.6.0. I tried to find a document that can explain
>>>> what these mean, but St. Google wasn't of much help. So, I looked at
>>>> the code to try and decipher what they would mean and from what I can
>>>> tell
>>>>
>>>> "DID_NOT_FIND_LOAD_ONLY_MAP_PLAN" means that there is a map plan that
>>>> meets one of the following conditions
>>>>
>>>> 1) has no leaf
>>>> 2) has more than one leaf
>>>> 3) has no root
>>>> 4) has more than one root
>>>> 5) the leaf is not equivalent to the root
>>>>
>>>> "MULTI_LEAF_MAP" apparently means that there are either zero or >=2
>>>> leaves on a map plan.
>>>>
>>>> So, I'm guessing that the DID_NOT_FIND_LOAD_ONLY_MAP_PLAN warnings are
>>>> coming from having 2 leaves. Unfortunately, I have no clue what that
>>>> means. Can anyone shed some light on what these warnings mean, if I
>>>> need to care about them and what I should look for to get rid of them
>>>> (if they are, in fact, not good)?
>>>>
>>>> Also, if the meaning of these warnings is documented somewhere and
>>>> Google just couldn't find it, please point me to the documentation.
>>>>
>>>> --Eric Tschetter
>>>>
>>>
>>
>
Re: MULTI_LEAF_MAP and DID_NOT_FIND_LOAD_ONLY_MAP_PLAN
Posted by Ashutosh Chauhan <as...@gmail.com>.
Hi Eric,
What you wrote is mostly true. A distilled down script generating same
warnings will be helpful. Thing is it seems that invariants which
should always hold (in theory) on generated map-reduce plan from query
are getting violated. I would like to see the script which can make
this happen. This might be a bug.
Ashutosh
On Wed, Mar 31, 2010 at 13:36, Eric Tschetter <ec...@gmail.com> wrote:
> Ok, so if I'm understanding you correctly, the warnings are basically
> Pig saying that it cannot apply a specific optimization, is that
> correct? If so, then might I make a suggestion that they not show up
> as "WARNING" but as "INFO" or something. Also, a slightly more
> meaningful message (something like, "Optimization XX was not able to
> be applied because of YY") might be helpful. It also sounds like I
> can safely ignore them as they won't affect the meaning of the pig
> script, just how it is actually executed.
>
> If this is wrong, I can try to distill down the script and get the
> same warnings.
>
> --Eric
>
>
>
> On Tue, Mar 30, 2010 at 10:37 PM, Ashutosh Chauhan
> <as...@gmail.com> wrote:
>> After Pig compiles a query into a series of map-reduce plans, it once
>> again iterate through those jobs trying to spot the opportunities of
>> further optimizations. While visiting such compiled plan, there are
>> certain invariants which must always hold. If Pig finds contrary to
>> it, it backs out and doesn't try to apply that optimization step. It
>> seems that you are running into that situation.
>> How this affects computation of your query I am not sure. Can you
>> paste stripped down version of your query which generates these
>> warning messages?
>>
>> Ashutosh
>>
>> On Fri, Mar 26, 2010 at 10:55, Eric Tschetter <ec...@gmail.com> wrote:
>>> I'm writing a fairly involved pig script to do some data munging and
>>> after all was said and done, I end up getting the warnings mentioned
>>> in the subject.
>>>
>>> The grunt output is actually:
>>>
>>> 2010-03-26 09:42:33,245 [main] WARN
>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>> - Encountered Warning DID_NOT_FIND_LOAD_ONLY_MAP_PLAN 2 time(s).
>>> 2010-03-26 09:42:33,250 [main] WARN
>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>>> - Encountered Warning MULTI_LEAF_MAP 1 time(s).
>>>
>>> This is on pig 0.6.0. I tried to find a document that can explain
>>> what these mean, but St. Google wasn't of much help. So, I looked at
>>> the code to try and decipher what they would mean and from what I can
>>> tell
>>>
>>> "DID_NOT_FIND_LOAD_ONLY_MAP_PLAN" means that there is a map plan that
>>> meets one of the following conditions
>>>
>>> 1) has no leaf
>>> 2) has more than one leaf
>>> 3) has no root
>>> 4) has more than one root
>>> 5) the leaf is not equivalent to the root
>>>
>>> "MULTI_LEAF_MAP" apparently means that there are either zero or >=2
>>> leaves on a map plan.
>>>
>>> So, I'm guessing that the DID_NOT_FIND_LOAD_ONLY_MAP_PLAN warnings are
>>> coming from having 2 leaves. Unfortunately, I have no clue what that
>>> means. Can anyone shed some light on what these warnings mean, if I
>>> need to care about them and what I should look for to get rid of them
>>> (if they are, in fact, not good)?
>>>
>>> Also, if the meaning of these warnings is documented somewhere and
>>> Google just couldn't find it, please point me to the documentation.
>>>
>>> --Eric Tschetter
>>>
>>
>
Re: MULTI_LEAF_MAP and DID_NOT_FIND_LOAD_ONLY_MAP_PLAN
Posted by Eric Tschetter <ec...@gmail.com>.
Ok, so if I'm understanding you correctly, the warnings are basically
Pig saying that it cannot apply a specific optimization, is that
correct? If so, then might I make a suggestion that they not show up
as "WARNING" but as "INFO" or something. Also, a slightly more
meaningful message (something like, "Optimization XX was not able to
be applied because of YY") might be helpful. It also sounds like I
can safely ignore them as they won't affect the meaning of the pig
script, just how it is actually executed.
If this is wrong, I can try to distill down the script and get the
same warnings.
--Eric
On Tue, Mar 30, 2010 at 10:37 PM, Ashutosh Chauhan
<as...@gmail.com> wrote:
> After Pig compiles a query into a series of map-reduce plans, it once
> again iterate through those jobs trying to spot the opportunities of
> further optimizations. While visiting such compiled plan, there are
> certain invariants which must always hold. If Pig finds contrary to
> it, it backs out and doesn't try to apply that optimization step. It
> seems that you are running into that situation.
> How this affects computation of your query I am not sure. Can you
> paste stripped down version of your query which generates these
> warning messages?
>
> Ashutosh
>
> On Fri, Mar 26, 2010 at 10:55, Eric Tschetter <ec...@gmail.com> wrote:
>> I'm writing a fairly involved pig script to do some data munging and
>> after all was said and done, I end up getting the warnings mentioned
>> in the subject.
>>
>> The grunt output is actually:
>>
>> 2010-03-26 09:42:33,245 [main] WARN
>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>> - Encountered Warning DID_NOT_FIND_LOAD_ONLY_MAP_PLAN 2 time(s).
>> 2010-03-26 09:42:33,250 [main] WARN
>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
>> - Encountered Warning MULTI_LEAF_MAP 1 time(s).
>>
>> This is on pig 0.6.0. I tried to find a document that can explain
>> what these mean, but St. Google wasn't of much help. So, I looked at
>> the code to try and decipher what they would mean and from what I can
>> tell
>>
>> "DID_NOT_FIND_LOAD_ONLY_MAP_PLAN" means that there is a map plan that
>> meets one of the following conditions
>>
>> 1) has no leaf
>> 2) has more than one leaf
>> 3) has no root
>> 4) has more than one root
>> 5) the leaf is not equivalent to the root
>>
>> "MULTI_LEAF_MAP" apparently means that there are either zero or >=2
>> leaves on a map plan.
>>
>> So, I'm guessing that the DID_NOT_FIND_LOAD_ONLY_MAP_PLAN warnings are
>> coming from having 2 leaves. Unfortunately, I have no clue what that
>> means. Can anyone shed some light on what these warnings mean, if I
>> need to care about them and what I should look for to get rid of them
>> (if they are, in fact, not good)?
>>
>> Also, if the meaning of these warnings is documented somewhere and
>> Google just couldn't find it, please point me to the documentation.
>>
>> --Eric Tschetter
>>
>
Re: MULTI_LEAF_MAP and DID_NOT_FIND_LOAD_ONLY_MAP_PLAN
Posted by Ashutosh Chauhan <as...@gmail.com>.
After Pig compiles a query into a series of map-reduce plans, it once
again iterate through those jobs trying to spot the opportunities of
further optimizations. While visiting such compiled plan, there are
certain invariants which must always hold. If Pig finds contrary to
it, it backs out and doesn't try to apply that optimization step. It
seems that you are running into that situation.
How this affects computation of your query I am not sure. Can you
paste stripped down version of your query which generates these
warning messages?
Ashutosh
On Fri, Mar 26, 2010 at 10:55, Eric Tschetter <ec...@gmail.com> wrote:
> I'm writing a fairly involved pig script to do some data munging and
> after all was said and done, I end up getting the warnings mentioned
> in the subject.
>
> The grunt output is actually:
>
> 2010-03-26 09:42:33,245 [main] WARN
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
> - Encountered Warning DID_NOT_FIND_LOAD_ONLY_MAP_PLAN 2 time(s).
> 2010-03-26 09:42:33,250 [main] WARN
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
> - Encountered Warning MULTI_LEAF_MAP 1 time(s).
>
> This is on pig 0.6.0. I tried to find a document that can explain
> what these mean, but St. Google wasn't of much help. So, I looked at
> the code to try and decipher what they would mean and from what I can
> tell
>
> "DID_NOT_FIND_LOAD_ONLY_MAP_PLAN" means that there is a map plan that
> meets one of the following conditions
>
> 1) has no leaf
> 2) has more than one leaf
> 3) has no root
> 4) has more than one root
> 5) the leaf is not equivalent to the root
>
> "MULTI_LEAF_MAP" apparently means that there are either zero or >=2
> leaves on a map plan.
>
> So, I'm guessing that the DID_NOT_FIND_LOAD_ONLY_MAP_PLAN warnings are
> coming from having 2 leaves. Unfortunately, I have no clue what that
> means. Can anyone shed some light on what these warnings mean, if I
> need to care about them and what I should look for to get rid of them
> (if they are, in fact, not good)?
>
> Also, if the meaning of these warnings is documented somewhere and
> Google just couldn't find it, please point me to the documentation.
>
> --Eric Tschetter
>