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The "LoadStoreMigrationGuide" page has been changed by PradeepKamath.
http://wiki.apache.org/pig/LoadStoreMigrationGuide?action=diff&rev1=31&rev2=32

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  == Table mapping old API calls to new API calls in rough order of call 
sequence ==
  ||'''Old Method in !LoadFunc''' ||'''Equivalent New Method''' ||'''New 
Class/Interface in which method is present''' ||'''Explanation''' ||
- ||No equivalent method ||setUDFContextSignature() ||!LoadFunc ||This method 
will be called by Pig both in the front end and back end to pass a unique 
signature to the Loader. The signature can be used to store into the 
!UDFContext any information which the Loader needs to store between various 
method invocations in the front end and back end. A use case is to store 
!RequiredFieldList passed to it in 
!LoadPushDown.pushProjection(!RequiredFieldList) for use in the back end before 
returning tuples in getNext(). The default implementation in !LoadFunc has an 
empty body. ||
+ ||No equivalent method ||setUDFContextSignature() ||!LoadFunc ||This method 
will be called by Pig both in the front end and back end to pass a unique 
signature to the Loader. The signature can be used to store into the 
!UDFContext any information which the Loader needs to store between various 
method invocations in the front end and back end. A use case is to store 
!RequiredFieldList passed to it in 
!LoadPushDown.pushProjection(!RequiredFieldList) for use in the back end before 
returning tuples in getNext(). The default implementation in !LoadFunc has an 
empty body. This method will be called before other methods.||
  ||No equivalent method ||relativeToAbsolutePath() ||!LoadFunc ||Pig runtime 
will call this method to allow the Loader to convert a relative load location 
to an absolute location. The default implementation provided in !LoadFunc 
handles this for !FileSystem locations. If the load source is something else, 
loader implementation may choose to override this. ||
  ||determineSchema() ||getSchema() ||!LoadMetadata ||determineSchema() was 
used by old code to ask the loader to provide a schema for the data returned by 
it - the same semantics are now achieved through getSchema() of the 
!LoadMetadata interface. !LoadMetadata is an optional interface for loaders to 
implement - if a loader does not implement it, this will indicate to the pig 
runtime that the loader cannot return a schema for the data ||
  ||fieldsToRead() ||pushProject() ||!LoadPushDown ||fieldsToRead() was used by 
old code to convey to the loader the exact fields required by the pig script 
-the same semantics are now achieved through pushProject() of the !LoadPushDown 
interface. !LoadPushDown is an optional interface for loaders to implement - if 
a loader does not implement it, this will indicate to the pig runtime that the 
loader is not capable of returning just the required fields and will return all 
fields in the data. If a loader implementation is able to efficiently return 
only required fields, it should implement !LoadPushDown to improve query 
performance ||
@@ -35, +35 @@

  
  == Table mapping old API calls to new API calls in rough order of call 
sequence ==
  ||'''Old Method in !StoreFunc''' ||'''Equivalent New Method''' ||'''New 
Class/Interface in which method is present''' ||'''Explanation''' ||
- ||No equivalent method ||setStoreFuncUDFContextSignature() ||!StoreFunc 
||This method will be called by Pig both in the front end and back end to pass 
a unique signature to the Storer. The signature can be used to store into the 
UDFContext any information which the Storer needs to store between various 
method invocations in the front end and back end. The default implementation in 
!StoreFunc has an empty body. ||
+ ||No equivalent method ||setStoreFuncUDFContextSignature() ||!StoreFunc 
||This method will be called by Pig both in the front end and back end to pass 
a unique signature to the Storer. The signature can be used to store into the 
UDFContext any information which the Storer needs to store between various 
method invocations in the front end and back end. The default implementation in 
!StoreFunc has an empty body. This method will be called before other methods.||
  ||No equivalent method ||relToAbsPathForStoreLocation() ||!StoreFunc ||Pig 
runtime will call this method to allow the Storer to convert a relative store 
location to an absolute location. An implementation is provided in !StoreFunc 
which handles this for !FileSystem based locations. ||
- ||No equivalent method ||checkSchema() ||!StoreFunc ||A Store function should 
implement this function to check that a given schema describing the data to be 
written is acceptable to it. The default implementation in !StoreFunc has an 
empty body.||
+ ||No equivalent method ||checkSchema() ||!StoreFunc ||A Store function should 
implement this function to check that a given schema describing the data to be 
written is acceptable to it. The default implementation in !StoreFunc has an 
empty body. This method will be called before any calls to setStoreLocation().||
  ||No equivalent method ||setStoreLocation() ||!StoreFunc ||This method is 
called by Pig to communicate the store location to the storer. The storer 
should use this method to communicate the same information to the underlying 
!OutputFormat. This method is called multiple times by pig - implementations 
should bear in mind that this method is called multiple times and should ensure 
there are no inconsistent side effects due to the multiple calls. ||
  ||getStorePreparationClass() ||getOutputFormat() ||!StoreFunc ||In the old 
API, getStorePreparationClass() was the means by which the implementation could 
communicate to Pig the !OutputFormat to use for writing - this is now achieved 
through getOutputFormat(). getOutputFormat() is NOT an optional method and 
implementation SHOULD provide an !OutputFormat to use. The methods in the 
!OutputFormat (and underlying !RecordWriter and !OutputCommitter) will be 
called by pig in the same manner (and in the same context) as by Hadoop in a 
map-reduce java program. '''If the !OutputFormat is a hadoop packaged one, the 
implementation should use the new API based one in org.apache.hadoop.mapreduce. 
If it is a custom !OutputFormat, it should be implemented using the new API 
under org.apache.hadoop.mapreduce'''. The checkOutputSpecs() method of the 
!OutputFormat will be called by pig to check the output location up-front. This 
method will also be called as part of the Hadoop call sequence when the job is 
launched. So implementations should ensure that this method can be called 
multiple times without inconsistent side effects. ||
  ||bindTo() ||prepareToWrite() ||!StoreFunc ||bindTo() was the old method 
which would provide an !OutputStream among other things to the !StoreFunc. The 
!StoreFunc implementation would then write to the !OutputStream in putNext(). 
In the new API, writing of the data is through the !OutputFormat provided by 
the !StoreFunc. So the equivalent call is prepareToWrite() wherein the 
!RecordWriter associated with the !OutputFormat provided by the !StoreFunc is 
passed to the !StoreFunc. The !RecordWriter can then be used by the 
implementation in putNext() to write a tuple representing a record of data in a 
manner expected by the !RecordWriter. ||

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