[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12727834#action_12727834
]
Pradeep Kamath commented on PIG-820:
Review comments - two observations:
1. In PigStorage the skip() implementation should do an extra skip(1) if the
byte at n-1 is not -1 (i.e. after skipping n-1, if the stream is not at EOF,
there should be a skip(1), so that n bytes are skipped in all).
2. The comment for getSampledTuple() contains:
{code}
/**
* Get the next sampled tuple from the stream.
* Those loaders which can appropriately return the next tuple after
* skipping in the stream(e.g. BinStorage) can in turn call their
getNext()
* for implementing this method. Those who cannot (e.g. PigStorage) need
to
* provide their own implementation.
* Samplers must call this method to get next tuple and should never
directly call
* underlying loader's getNext() method.
* @return the next tuple after skipping or null if there are no more
tuples
* to be processed.
*/
{code}
The comment can be updated to be explicit about the context in which
getSampledTuple() would be called- something along the lines of
{noformat}
getSampledTuple() method will be called after a call to skip(). Hence the
loader implementation would have to handle the case wherein the current read
position
in the stream is not at the beginning of a record and correctly give the next
tuple starting from the current read position. In particular, the
implementation would need to handle the following cases:
1) The current read position for the input stream is at the beginning of the
stream - in this case getSampledTuple() should return the tuple repesenting the
first tuple in the stream
2) The current read position for the input stream is in the middle of a record
- in this case getSampledTuple() should return the tuple representing the next
record by reading forward in the stream
3) The current read position for the input stream is exactly at the beginning
of a record - in this case getSampledTuple() should return the tuple
representing the record at current read position
4) The current read position for the input stream is beyond end of file - in
this case getSampledTuple() should return null
{noformat}
To keep the comment from being very verbose, the implementation details
(whether to delegate to getNext() or not) can be omitted.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch,
pig-820_v4.patch, pig-820_v5.patch, pig-820_v6.patch, pig-820_v7.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would
[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12727907#action_12727907
]
Hadoop QA commented on PIG-820:
---
-1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12412695/pig-820_v8.patch
against trunk revision 791048.
+1 @author. The patch does not contain any @author tags.
-1 tests included. The patch doesn't appear to include any new or modified
tests.
Please justify why no tests are needed for this patch.
+1 javadoc. The javadoc tool did not generate any warning messages.
+1 javac. The applied patch does not increase the total number of javac
compiler warnings.
+1 findbugs. The patch does not introduce any new Findbugs warnings.
+1 release audit. The applied patch does not increase the total number of
release audit warnings.
+1 core tests. The patch passed core unit tests.
+1 contrib tests. The patch passed contrib unit tests.
Test results:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/114/testReport/
Findbugs warnings:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/114/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/114/console
This message is automatically generated.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch,
pig-820_v4.patch, pig-820_v5.patch, pig-820_v6.patch, pig-820_v7.patch,
pig-820_v8.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
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[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12725602#action_12725602
]
Hudson commented on PIG-820:
Integrated in Pig-trunk #490 (See
[http://hudson.zones.apache.org/hudson/job/Pig-trunk/490/])
: Change RandomSampleLoader to take a LoadFunc instead of extending
BinStorage. Added new Samplable interface for loaders to implement allowing
them to be used by RandomSampleLoader.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch,
pig-820_v4.patch, pig-820_v5.patch, pig-820_v6.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12724632#action_12724632
]
Hadoop QA commented on PIG-820:
---
+1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12411723/pig-820_v5.patch
against trunk revision 788174.
+1 @author. The patch does not contain any @author tags.
+1 tests included. The patch appears to include 6 new or modified tests.
+1 javadoc. The javadoc tool did not generate any warning messages.
+1 javac. The applied patch does not increase the total number of javac
compiler warnings.
+1 findbugs. The patch does not introduce any new Findbugs warnings.
+1 release audit. The applied patch does not increase the total number of
release audit warnings.
+1 core tests. The patch passed core unit tests.
+1 contrib tests. The patch passed contrib unit tests.
Test results:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/102/testReport/
Findbugs warnings:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/102/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/102/console
This message is automatically generated.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch,
pig-820_v4.patch, pig-820_v5.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12724717#action_12724717
]
Pradeep Kamath commented on PIG-820:
+1
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch,
pig-820_v4.patch, pig-820_v5.patch, pig-820_v6.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12724769#action_12724769
]
Hadoop QA commented on PIG-820:
---
+1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12411945/pig-820_v6.patch
against trunk revision 788174.
+1 @author. The patch does not contain any @author tags.
+1 tests included. The patch appears to include 6 new or modified tests.
+1 javadoc. The javadoc tool did not generate any warning messages.
+1 javac. The applied patch does not increase the total number of javac
compiler warnings.
+1 findbugs. The patch does not introduce any new Findbugs warnings.
+1 release audit. The applied patch does not increase the total number of
release audit warnings.
+1 core tests. The patch passed core unit tests.
+1 contrib tests. The patch passed contrib unit tests.
Test results:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/104/testReport/
Findbugs warnings:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/104/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/104/console
This message is automatically generated.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch,
pig-820_v4.patch, pig-820_v5.patch, pig-820_v6.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
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-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12724204#action_12724204
]
Pradeep Kamath commented on PIG-820:
In SampleOptimizer the following should change:
{code}
// First argument is name of loader function to subsume, this we want
to set for
// ourselves.
rslargs[0] = predFs.getFuncName();
to
// First argument is name of loader function with constructor args to
subsume, this we want to set for
// ourselves.
rslargs[0] = predFs.getFuncSpec().toString();
{code}
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch,
pig-820_v4.patch, pig-820_v5.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12723204#action_12723204
]
Alan Gates commented on PIG-820:
+1
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
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-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12723316#action_12723316
]
Ashutosh Chauhan commented on PIG-820:
--
Thanks Alan and Pradeep for the review.
Will be incorporating SampleOptimizer changes.
Constructor of RandomSampleLoader can only take string args since it is
instantiated from FuncSpec on backend. So, cant make changes to types of
RandomSampleLoader constructor argument. However, instead of String having
classname of loader , String version of FuncSpec can be used so that loader
with correct constructor gets instantiated.
Will be uploading a new patch soon.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Ashutosh Chauhan
Fix For: 0.4.0
Attachments: pig-820.patch, pig-820_v2.patch, pig-820_v3.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
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[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12722706#action_12722706
]
Ashutosh Chauhan commented on PIG-820:
--
In the patch RandomSampleLoader is marked as serializable and loader field in
it is marked as transient. Since loader is initialized in constructor and is
used later on findbugs is complaining : This class contains a field that is
updated at multiple places in the class, thus it seems to be part of the state
of the class.However, since the field is marked as transient and not set in
readObject or readResolve, it will contain the default value in any
deserialized instance of the class. However there is no need for
RandomSampleLoader to implement Serializable anyway (and thus loader to be
marked as transient) because loader is reconstructed from FunSpec later on.
Because of this reason, both PigStorage and BinStorage also doesnt implement
serializable. Will be submitting a new patch with the required changes.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Alan Gates
Attachments: pig-820.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
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[jira] Commented: (PIG-820) PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume another loader
[
https://issues.apache.org/jira/browse/PIG-820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12722286#action_12722286
]
Hadoop QA commented on PIG-820:
---
-1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12411325/pig-820.patch
against trunk revision 786694.
+1 @author. The patch does not contain any @author tags.
+1 tests included. The patch appears to include 6 new or modified tests.
+1 javadoc. The javadoc tool did not generate any warning messages.
+1 javac. The applied patch does not increase the total number of javac
compiler warnings.
-1 findbugs. The patch appears to introduce 1 new Findbugs warnings.
+1 release audit. The applied patch does not increase the total number of
release audit warnings.
+1 core tests. The patch passed core unit tests.
+1 contrib tests. The patch passed contrib unit tests.
Test results:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/96/testReport/
Findbugs warnings:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/96/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output:
http://hudson.zones.apache.org/hudson/job/Pig-Patch-minerva.apache.org/96/console
This message is automatically generated.
PERFORMANCE: The RandomSampleLoader should be changed to allow it subsume
another loader
-
Key: PIG-820
URL: https://issues.apache.org/jira/browse/PIG-820
Project: Pig
Issue Type: Improvement
Components: impl
Affects Versions: 0.3.0, 0.4.0
Reporter: Alan Gates
Assignee: Alan Gates
Attachments: pig-820.patch
Currently a sampling job requires that data already be stored in
BinaryStorage format, since RandomSampleLoader extends BinaryStorage. For
order by this
has mostly been acceptable, because users tend to use order by at the end of
their script where other MR jobs have already operated on the data and thus it
is already being stored in BinaryStorage. For pig scripts that just did an
order by, an entire MR job is required to read the data and write it out
in BinaryStorage format.
As we begin work on join algorithms that will require sampling, this
requirement to read the entire input and write it back out will not be
acceptable.
Join is often the first operation of a script, and thus is much more likely
to trigger this useless up front translation job.
Instead RandomSampleLoader can be changed to subsume an existing loader,
using the user specified loader to read the tuples while handling the skipping
between tuples itself. This will require the subsumed loader to implement a
Samplable Interface, that will look something like:
{code}
public interface SamplableLoader extends LoadFunc {
/**
* Skip ahead in the input stream.
* @param n number of bytes to skip
* @return number of bytes actually skipped. The return semantics are
* exactly the same as {...@link java.io.InpuStream#skip(long)}
*/
public long skip(long n) throws IOException;
/**
* Get the current position in the stream.
* @return position in the stream.
*/
public long getPosition() throws IOException;
}
{code}
The MRCompiler would then check if the loader being used to load data
implemented the SamplableLoader interface. If so, rather than create an
initial MR
job to do the translation it would create the sampling job, having
RandomSampleLoader use the user specified loader.
--
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-
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