org.apache.pig.backend.hadoop.hbase

Class HBaseStorage

java.lang.Object

org.apache.pig.LoadFunc

org.apache.pig.backend.hadoop.hbase.HBaseStorage

All Implemented Interfaces:

CollectableLoadFunc, LoadPushDown, OrderedLoadFunc, StoreFuncInterface, StoreResources

public class HBaseStorage
extends LoadFunc
implements StoreFuncInterface, LoadPushDown, OrderedLoadFunc, StoreResources, CollectableLoadFunc

A HBase implementation of LoadFunc and StoreFunc.

Below is an example showing how to load data from HBase:

raw = LOAD 'hbase://SampleTable'
       USING org.apache.pig.backend.hadoop.hbase.HBaseStorage(
       'info:first_name info:last_name friends:* info:*', '-loadKey true -limit 5')
       AS (id:bytearray, first_name:chararray, last_name:chararray, friends_map:map[], info_map:map[]);
 

This example loads data redundantly from the info column family just to illustrate usage. Note that the row key is inserted first in the result schema. To load only column names that start with a given prefix, specify the column name with a trailing '*'. For example passing friends:bob_* to the constructor in the above example would cause only columns that start with bob_ to be loaded.

Note that when using a prefix like friends:bob_*, explicit HBase filters are set for all columns and prefixes specified. Querying HBase with many filters can cause performance degredation. This is typically seen when mixing one or more prefixed descriptors with a large list of columns. In that case better perfomance will be seen by either loading the entire family via friends:* or by specifying explicit column descriptor names.

Below is an example showing how to store data into HBase:

copy = STORE raw INTO 'hbase://SampleTableCopy'
       USING org.apache.pig.backend.hadoop.hbase.HBaseStorage(
       'info:first_name info:last_name friends:* info:*');
 

Note that STORE will expect the first value in the tuple to be the row key. Scalars values need to map to an explicit column descriptor and maps need to map to a column family name. In the above examples, the friends column family data from SampleTable will be written to a buddies column family in the SampleTableCopy table.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	HBaseStorage.ColumnInfo Class to encapsulate logic around which column names were specified in each position of the column list.

Nested classes/interfaces inherited from interface org.apache.pig.LoadPushDown

LoadPushDown.OperatorSet, LoadPushDown.RequiredField, LoadPushDown.RequiredFieldList, LoadPushDown.RequiredFieldResponse

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	gt_
protected byte[]	gte_
protected byte[]	lt_
protected byte[]	lte_

Constructor Summary

Constructors

Constructor and Description
HBaseStorage(String columnList) Constructor.
HBaseStorage(String columnList, String optString) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	checkSchema(ResourceSchema s) Set the schema for data to be stored.
void	cleanupOnFailure(String location, org.apache.hadoop.mapreduce.Job job) This method will be called by Pig if the job which contains this store fails.
void	cleanupOnSuccess(String location, org.apache.hadoop.mapreduce.Job job) This method will be called by Pig if the job which contains this store is successful, and some cleanup of intermediate resources is required.
org.apache.hadoop.hbase.client.Delete	createDelete(Object key, byte type, long timestamp) Public method to initialize a Delete.
org.apache.hadoop.hbase.client.Put	createPut(Object key, byte type) Public method to initialize a Put.
void	ensureAllKeyInstancesInSameSplit() When this method is called, Pig is communicating to the Loader that it must load data such that all instances of a key are in same split.
List<HBaseStorage.ColumnInfo>	getColumnInfoList() Returns the ColumnInfo list so external objects can inspect it.
List<LoadPushDown.OperatorSet>	getFeatures() Determine the operators that can be pushed to the loader.
org.apache.hadoop.mapreduce.InputFormat	getInputFormat() This will be called during planning on the front end.
LoadCaster	getLoadCaster() Set up the caster to use for reading values out of, and writing to, HBase.
Tuple	getNext() Retrieves the next tuple to be processed.
org.apache.hadoop.mapreduce.OutputFormat	getOutputFormat() Return the OutputFormat associated with StoreFuncInterface.
List<String>	getShipFiles() Allow a LoadFunc to specify a list of files located locally and would like to ship to backend (through distributed cache).
org.apache.hadoop.io.WritableComparable<org.apache.hadoop.hbase.mapreduce.TableSplit>	getSplitComparable(org.apache.hadoop.mapreduce.InputSplit split) The WritableComparable object returned will be used to compare the position of different splits in an ordered stream
void	prepareToRead(org.apache.hadoop.mapreduce.RecordReader reader, PigSplit split) Initializes LoadFunc for reading data.
void	prepareToWrite(org.apache.hadoop.mapreduce.RecordWriter writer) Initialize StoreFuncInterface to write data.
LoadPushDown.RequiredFieldResponse	pushProjection(LoadPushDown.RequiredFieldList requiredFieldList) Indicate to the loader fields that will be needed.
void	putNext(Tuple t) Write a tuple to the data store.
String	relativeToAbsolutePath(String location, org.apache.hadoop.fs.Path curDir) This method is called by the Pig runtime in the front end to convert the input location to an absolute path if the location is relative.
String	relToAbsPathForStoreLocation(String location, org.apache.hadoop.fs.Path curDir) This method is called by the Pig runtime in the front end to convert the output location to an absolute path if the location is relative.
protected void	setColumnInfoList(List<HBaseStorage.ColumnInfo> columnInfoList) Updates the ColumnInfo List.
void	setLocation(String location, org.apache.hadoop.mapreduce.Job job) Communicate to the loader the location of the object(s) being loaded.
void	setStoreFuncUDFContextSignature(String signature) This method will be called by Pig both in the front end and back end to pass a unique signature to the StoreFuncInterface which it can use to store information in the UDFContext which it needs to store between various method invocations in the front end and back end.
void	setStoreLocation(String location, org.apache.hadoop.mapreduce.Job job) Communicate to the storer the location where the data needs to be stored.
void	setUDFContextSignature(String signature) This method will be called by Pig both in the front end and back end to pass a unique signature to the LoadFunc.
protected void	storeProjectedFieldNames(LoadPushDown.RequiredFieldList requiredFieldList) Stores the requiredFieldsList as a serialized object so it can be fetched on the cluster.

Methods inherited from class org.apache.pig.LoadFunc

getAbsolutePath, getCacheFiles, getPathStrings, join, warn

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.pig.StoreResources

getCacheFiles

Field Detail

gt_

protected transient byte[] gt_

gte_

protected transient byte[] gte_

lt_

protected transient byte[] lt_

lte_

protected transient byte[] lte_

Constructor Detail

HBaseStorage

public HBaseStorage(String columnList)
             throws org.apache.commons.cli.ParseException,
                    IOException

Constructor. Construct a HBase Table LoadFunc and StoreFunc to load or store the cells of the provided columns.

Parameters:

columnList - columnlist that is a presented string delimited by space and/or commas. To retreive all columns in a column family Foo, specify a column as either Foo: or Foo:*. To fetch only columns in the CF that start with bar, specify Foo:bar*. The resulting tuple will always be the size of the number of tokens in columnList. Items in the tuple will be scalar values when a full column descriptor is specified, or a map of column descriptors to values when a column family is specified.

Throws:

org.apache.commons.cli.ParseException - when unable to parse arguments

IOException

HBaseStorage

public HBaseStorage(String columnList,
            String optString)
             throws org.apache.commons.cli.ParseException,
                    IOException

Constructor. Construct a HBase Table LoadFunc and StoreFunc to load or store.

Parameters:

columnList -

optString - Loader options. Known options:

• -loadKey=(true|false) Load the row key as the first column
• -gt=minKeyVal
• -lt=maxKeyVal
• -gte=minKeyVal
• -lte=maxKeyVal
• -regex=match regex on KeyVal
• -limit=numRowsPerRegion max number of rows to retrieve per region
• -maxResultsPerColumnFamily= Limit the maximum number of values returned per row per column family
• -delim=char delimiter to use when parsing column names (default is space or comma)
• -ignoreWhitespace=(true|false) ignore spaces when parsing column names (default true)
• -cacheBlocks=(true|false) Set whether blocks should be cached for the scan (default false).
• -caching=numRows number of rows to cache (faster scans, more memory).
• -noWAL=(true|false) Sets the write ahead to false for faster loading.
• -minTimestamp= Scan's timestamp for min timeRange
• -maxTimestamp= Scan's timestamp for max timeRange
• -timestamp= Scan's specified timestamp
• -includeTimestamp= Record will include the timestamp after the rowkey on store (rowkey, timestamp, ...)
• -includeTombstone= Record will include a tombstone marker on store after the rowKey and timestamp (if included) (rowkey, [timestamp,] tombstone, ...)
• -caster=(HBaseBinaryConverter|Utf8StorageConverter) Utf8StorageConverter is the default To be used with extreme caution, since this could result in data loss (see http://hbase.apache.org/book.html#perf.hbase.client.putwal).

Throws:

org.apache.commons.cli.ParseException

IOException

Method Detail

getColumnInfoList

public List<HBaseStorage.ColumnInfo> getColumnInfoList()

Returns the ColumnInfo list so external objects can inspect it.

Returns:

List of ColumnInfo objects

setColumnInfoList

protected void setColumnInfoList(List<HBaseStorage.ColumnInfo> columnInfoList)

Updates the ColumnInfo List. Use this if you need to implement custom projections

storeProjectedFieldNames

protected void storeProjectedFieldNames(LoadPushDown.RequiredFieldList requiredFieldList)
                                 throws FrontendException

Stores the requiredFieldsList as a serialized object so it can be fetched on the cluster. If you plan to overwrite pushProjection, you need to call this with the requiredFieldList so it they can be accessed on the cluster.

Throws:

FrontendException

getNext

public Tuple getNext()
              throws IOException

Description copied from class: LoadFunc

Retrieves the next tuple to be processed. Implementations should NOT reuse tuple objects (or inner member objects) they return across calls and should return a different tuple object in each call.

Specified by:

getNext in class LoadFunc

Returns:

the next tuple to be processed or null if there are no more tuples to be processed.

Throws:

IOException - if there is an exception while retrieving the next tuple

getInputFormat

public org.apache.hadoop.mapreduce.InputFormat getInputFormat()

Description copied from class: LoadFunc

This will be called during planning on the front end. This is the instance of InputFormat (rather than the class name) because the load function may need to instantiate the InputFormat in order to control how it is constructed.

Specified by:

getInputFormat in class LoadFunc

Returns:

the InputFormat associated with this loader.

prepareToRead

public void prepareToRead(org.apache.hadoop.mapreduce.RecordReader reader,
                 PigSplit split)

Description copied from class: LoadFunc

Initializes LoadFunc for reading data. This will be called during execution before any calls to getNext. The RecordReader needs to be passed here because it has been instantiated for a particular InputSplit.

Specified by:

prepareToRead in class LoadFunc

Parameters:

reader - RecordReader to be used by this instance of the LoadFunc

split - The input PigSplit to process

setUDFContextSignature

public void setUDFContextSignature(String signature)

Description copied from class: LoadFunc

This method will be called by Pig both in the front end and back end to pass a unique signature to the LoadFunc. The signature can be used to store into the UDFContext any information which the LoadFunc needs to store between various method invocations in the front end and back end. A use case is to store LoadPushDown.RequiredFieldList passed to it in LoadPushDown.pushProjection(RequiredFieldList) for use in the back end before returning tuples in LoadFunc.getNext(). This method will be call before other methods in LoadFunc

Overrides:

setUDFContextSignature in class LoadFunc

Parameters:

signature - a unique signature to identify this LoadFunc

setLocation

public void setLocation(String location,
               org.apache.hadoop.mapreduce.Job job)
                 throws IOException

Description copied from class: LoadFunc

Communicate to the loader the location of the object(s) being loaded. The location string passed to the LoadFunc here is the return value of LoadFunc.relativeToAbsolutePath(String, Path). Implementations should use this method to communicate the location (and any other information) to its underlying InputFormat through the Job object. This method will be called in the frontend and backend multiple times. 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.

Specified by:

setLocation in class LoadFunc

Parameters:

location - Location as returned by LoadFunc.relativeToAbsolutePath(String, Path)

job - the Job object store or retrieve earlier stored information from the UDFContext

Throws:

IOException - if the location is not valid.

getShipFiles

public List<String> getShipFiles()

Description copied from class: LoadFunc

Allow a LoadFunc to specify a list of files located locally and would like to ship to backend (through distributed cache). Check for FuncUtils for utility function to facilitate it The default implementation returns null.

Specified by:

getShipFiles in interface StoreResources

Overrides:

getShipFiles in class LoadFunc

Returns:

A list of files

relativeToAbsolutePath

public String relativeToAbsolutePath(String location,
                            org.apache.hadoop.fs.Path curDir)
                              throws IOException

Description copied from class: LoadFunc

This method is called by the Pig runtime in the front end to convert the input location to an absolute path if the location is relative. The loadFunc implementation is free to choose how it converts a relative location to an absolute location since this may depend on what the location string represent (hdfs path or some other data source)

Overrides:

relativeToAbsolutePath in class LoadFunc

Parameters:

location - location as provided in the "load" statement of the script

curDir - the current working direction based on any "cd" statements in the script before the "load" statement. If there are no "cd" statements in the script, this would be the home directory -

/user/ 

Returns:

the absolute location based on the arguments passed

Throws:

IOException - if the conversion is not possible

getLoadCaster

public LoadCaster getLoadCaster()
                         throws IOException

Set up the caster to use for reading values out of, and writing to, HBase.

Overrides:

getLoadCaster in class LoadFunc

Returns:

the LoadCaster associated with this loader. Returning null indicates that casts from byte array are not supported for this loader. construction

Throws:

IOException - if there is an exception during LoadCaster

getOutputFormat

public org.apache.hadoop.mapreduce.OutputFormat getOutputFormat()
                                                         throws IOException

Description copied from interface: StoreFuncInterface

Return the OutputFormat associated with StoreFuncInterface. This will be called on the front end during planning and on the backend during execution.

Specified by:

getOutputFormat in interface StoreFuncInterface

Returns:

the OutputFormat associated with StoreFuncInterface

Throws:

IOException - if an exception occurs while constructing the OutputFormat

checkSchema

public void checkSchema(ResourceSchema s)
                 throws IOException

Description copied from interface: StoreFuncInterface

Set the schema for data to be stored. This will be called on the front end during planning if the store is associated with a schema. A Store function should implement this function to check that a given schema is acceptable to it. For example, it can check that the correct partition keys are included; a storage function to be written directly to an OutputFormat can make sure the schema will translate in a well defined way.

Specified by:

checkSchema in interface StoreFuncInterface

Parameters:

s - to be checked

Throws:

IOException - if this schema is not acceptable. It should include a detailed error message indicating what is wrong with the schema.

prepareToWrite

public void prepareToWrite(org.apache.hadoop.mapreduce.RecordWriter writer)
                    throws IOException

Description copied from interface: StoreFuncInterface

Initialize StoreFuncInterface to write data. This will be called during execution before the call to putNext.

Specified by:

prepareToWrite in interface StoreFuncInterface

Parameters:

writer - RecordWriter to use.

Throws:

IOException - if an exception occurs during initialization

putNext

public void putNext(Tuple t)
             throws IOException

Description copied from interface: StoreFuncInterface

Write a tuple to the data store.

Specified by:

putNext in interface StoreFuncInterface

Parameters:

t - the tuple to store.

Throws:

IOException - if an exception occurs during the write

createDelete

public org.apache.hadoop.hbase.client.Delete createDelete(Object key,
                                                 byte type,
                                                 long timestamp)
                                                   throws IOException

Public method to initialize a Delete.

Parameters:

key -

type -

timestamp -

Returns:

new delete

Throws:

IOException

createPut

public org.apache.hadoop.hbase.client.Put createPut(Object key,
                                           byte type)
                                             throws IOException

Public method to initialize a Put. Used to allow assertions of how Puts are initialized by unit tests.

Parameters:

key -

type -

Returns:

new put

Throws:

IOException

relToAbsPathForStoreLocation

public String relToAbsPathForStoreLocation(String location,
                                  org.apache.hadoop.fs.Path curDir)
                                    throws IOException

Description copied from interface: StoreFuncInterface

This method is called by the Pig runtime in the front end to convert the output location to an absolute path if the location is relative. The StoreFuncInterface implementation is free to choose how it converts a relative location to an absolute location since this may depend on what the location string represent (hdfs path or some other data source). The static method LoadFunc.getAbsolutePath(java.lang.String, org.apache.hadoop.fs.Path) provides a default implementation for hdfs and hadoop local file system and it can be used to implement this method.

Specified by:

relToAbsPathForStoreLocation in interface StoreFuncInterface

Parameters:

location - location as provided in the "store" statement of the script

curDir - the current working direction based on any "cd" statements in the script before the "store" statement. If there are no "cd" statements in the script, this would be the home directory -

/user/ 

Returns:

the absolute location based on the arguments passed

Throws:

IOException - if the conversion is not possible

setStoreFuncUDFContextSignature

public void setStoreFuncUDFContextSignature(String signature)

Description copied from interface: StoreFuncInterface

This method will be called by Pig both in the front end and back end to pass a unique signature to the StoreFuncInterface which it can use to store information in the UDFContext which it needs to store between various method invocations in the front end and back end. This is necessary because in a Pig Latin script with multiple stores, the different instances of store functions need to be able to find their (and only their) data in the UDFContext object.

Specified by:

setStoreFuncUDFContextSignature in interface StoreFuncInterface

Parameters:

signature - a unique signature to identify this StoreFuncInterface

setStoreLocation

public void setStoreLocation(String location,
                    org.apache.hadoop.mapreduce.Job job)
                      throws IOException

Description copied from interface: StoreFuncInterface

Communicate to the storer the location where the data needs to be stored. The location string passed to the StoreFuncInterface here is the return value of StoreFuncInterface.relToAbsPathForStoreLocation(String, Path) This method will be called in the frontend and backend multiple times. 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. StoreFuncInterface.checkSchema(ResourceSchema) will be called before any call to StoreFuncInterface.setStoreLocation(String, Job).

Specified by:

setStoreLocation in interface StoreFuncInterface

Parameters:

location - Location returned by StoreFuncInterface.relToAbsPathForStoreLocation(String, Path)

job - The Job object

Throws:

IOException - if the location is not valid.

cleanupOnFailure

public void cleanupOnFailure(String location,
                    org.apache.hadoop.mapreduce.Job job)
                      throws IOException

Description copied from interface: StoreFuncInterface

This method will be called by Pig if the job which contains this store fails. Implementations can clean up output locations in this method to ensure that no incorrect/incomplete results are left in the output location

Specified by:

cleanupOnFailure in interface StoreFuncInterface

Parameters:

location - Location returned by StoreFuncInterface.relToAbsPathForStoreLocation(String, Path)

job - The Job object - this should be used only to obtain cluster properties through JobContextImpl.getConfiguration() and not to set/query any runtime job information.

Throws:

IOException

cleanupOnSuccess

public void cleanupOnSuccess(String location,
                    org.apache.hadoop.mapreduce.Job job)
                      throws IOException

Description copied from interface: StoreFuncInterface

This method will be called by Pig if the job which contains this store is successful, and some cleanup of intermediate resources is required. Implementations can clean up output locations in this method to ensure that no incorrect/incomplete results are left in the output location

Specified by:

cleanupOnSuccess in interface StoreFuncInterface

Parameters:

location - Location returned by StoreFuncInterface.relToAbsPathForStoreLocation(String, Path)

job - The Job object - this should be used only to obtain cluster properties through JobContextImpl.getConfiguration() and not to set/query any runtime job information.

Throws:

IOException

getFeatures

public List<LoadPushDown.OperatorSet> getFeatures()

Description copied from interface: LoadPushDown

Determine the operators that can be pushed to the loader. Note that by indicating a loader can accept a certain operator (such as selection) the loader is not promising that it can handle all selections. When it is passed the actual operators to push down it will still have a chance to reject them.

Specified by:

getFeatures in interface LoadPushDown

Returns:

list of all features that the loader can support

pushProjection

public LoadPushDown.RequiredFieldResponse pushProjection(LoadPushDown.RequiredFieldList requiredFieldList)
                                                  throws FrontendException

Description copied from interface: LoadPushDown

Indicate to the loader fields that will be needed. This can be useful for loaders that access data that is stored in a columnar format where indicating columns to be accessed a head of time will save scans. This method will not be invoked by the Pig runtime if all fields are required. So implementations should assume that if this method is not invoked, then all fields from the input are required. If the loader function cannot make use of this information, it is free to ignore it by returning an appropriate Response

Specified by:

pushProjection in interface LoadPushDown

Parameters:

requiredFieldList - RequiredFieldList indicating which columns will be needed. This structure is read only. User cannot make change to it inside pushProjection.

Returns:

Indicates which fields will be returned

Throws:

FrontendException

ensureAllKeyInstancesInSameSplit

public void ensureAllKeyInstancesInSameSplit()
                                      throws IOException

Description copied from interface: CollectableLoadFunc

When this method is called, Pig is communicating to the Loader that it must load data such that all instances of a key are in same split. Pig will make no further checks at runtime to ensure whether the contract is honored or not.

Specified by:

ensureAllKeyInstancesInSameSplit in interface CollectableLoadFunc

Throws:

IOException

getSplitComparable

public org.apache.hadoop.io.WritableComparable<org.apache.hadoop.hbase.mapreduce.TableSplit> getSplitComparable(org.apache.hadoop.mapreduce.InputSplit split)
                                                                                                         throws IOException

Description copied from interface: OrderedLoadFunc

The WritableComparable object returned will be used to compare the position of different splits in an ordered stream

Specified by:

getSplitComparable in interface OrderedLoadFunc

Parameters:

split - An InputSplit from the InputFormat underlying this loader.

Returns:

WritableComparable representing the position of the split in input

Throws:

IOException