问题
I'm trying to parse below input (there are 2 records in this input)using Elephantbird json loader
[{"node_disk_lnum_1":36,"node_disk_xfers_in_rate_sum":136.40000000000001,"node_disk_bytes_in_rate_22": 187392.0, "node_disk_lnum_7": 13}]
[{"node_disk_lnum_1": 36, "node_disk_xfers_in_rate_sum": 105.2,"node_disk_bytes_in_rate_22": 123084.8, "node_disk_lnum_7":13}]
Here is my syntax:
register '/home/data/Desktop/elephant-bird-pig-4.1.jar';
a = LOAD '/pig/tc1.log' USING
com.twitter.elephantbird.pig.load.JsonLoader('-nestedLoad') as (json:map[]);
b = FOREACH a GENERATE flatten(json#'node_disk_lnum_1') AS
node_disk_lnum_1,flatten(json#'node_disk_xfers_in_rate_sum') AS
node_disk_xfers_in_rate_sum,flatten(json#'node_disk_bytes_in_rate_22') AS
node_disk_bytes_in_rate_22, flatten(json#'node_disk_lnum_7') AS
node_disk_lnum_7;
DESCRIBE b;
b describe result:
b: {node_disk_lnum_1: bytearray,node_disk_xfers_in_rate_sum: bytearray,node_disk_bytes_in_rate_22: bytearray,node_disk_lnum_7: bytearray}
c = FOREACH b GENERATE node_disk_lnum_1;
DESCRIBE c;
c: {node_disk_lnum_1: bytearray}
DUMP c;
Expected Result:
36, 136.40000000000001, 187392.0, 13
36, 105.2, 123084.8, 13
Throwing the below error
2017-02-06 01:05:49,337 [main] INFO org.apache.pig.tools.pigstats.ScriptState - Pig features used in the script: UNKNOWN 2017-02-06 01:05:49,386 [main] INFO org.apache.pig.data.SchemaTupleBackend - Key [pig.schematuple] was not set... will not generate code. 2017-02-06 01:05:49,387 [main] INFO org.apache.pig.newplan.logical.optimizer.LogicalPlanOptimizer - {RULES_ENABLED=[AddForEach, ColumnMapKeyPrune, ConstantCalculator, GroupByConstParallelSetter, LimitOptimizer, LoadTypeCastInserter, MergeFilter, MergeForEach, PartitionFilterOptimizer, PredicatePushdownOptimizer, PushDownForEachFlatten, PushUpFilter, SplitFilter, StreamTypeCastInserter]} 2017-02-06 01:05:49,390 [main] INFO org.apache.pig.newplan.logical.rules.ColumnPruneVisitor - Map key required for a: $0->[node_disk_lnum_1, node_disk_xfers_in_rate_sum, node_disk_bytes_in_rate_22, node_disk_lnum_7]
2017-02-06 01:05:49,395 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MRCompiler - File concatenation threshold: 100 optimistic? false 2017-02-06 01:05:49,398 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer - MR plan size before optimization: 1 2017-02-06 01:05:49,398 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer - MR plan size after optimization: 1 2017-02-06 01:05:49,425 [main] INFO org.apache.pig.tools.pigstats.mapreduce.MRScriptState - Pig script settings are added to the job 2017-02-06 01:05:49,426 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.JobControlCompiler - mapred.job.reduce.markreset.buffer.percent is not set, set to default 0.3 2017-02-06 01:05:49,428 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 2998: Unhandled internal error. com/twitter/elephantbird/util/HadoopCompat
Please help what am I missing?
回答1:
You do not have any nested data in your json,so remove -nestedload
a = LOAD '/pig/tc1.log' USING com.twitter.elephantbird.pig.load.JsonLoader() as (json:map[]);
来源：https://stackoverflow.com/questions/42064795/apache-pig-elephantbirdjson-loader