uda-sample.h File Reference

#include <udf/udf.h>

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Functions
void	CountInit (FunctionContext *context, BigIntVal *val)
	This is an example of the COUNT aggregate function. More...
void	CountUpdate (FunctionContext *context, const IntVal &input, BigIntVal *val)
void	CountMerge (FunctionContext *context, const BigIntVal &src, BigIntVal *dst)
BigIntVal	CountFinalize (FunctionContext *context, const BigIntVal &val)
void	AvgInit (FunctionContext *context, BufferVal *val)
void	AvgUpdate (FunctionContext *context, const DoubleVal &input, BufferVal *val)
void	AvgMerge (FunctionContext *context, const BufferVal &src, BufferVal *dst)
DoubleVal	AvgFinalize (FunctionContext *context, const BufferVal &val)
void	StringConcatInit (FunctionContext *context, StringVal *val)
void	StringConcatUpdate (FunctionContext *context, const StringVal &arg1, const StringVal &arg2, StringVal *val)
void	StringConcatMerge (FunctionContext *context, const StringVal &src, StringVal *dst)
StringVal	StringConcatFinalize (FunctionContext *context, const StringVal &val)

Function Documentation

DoubleVal AvgFinalize	(	FunctionContext *	context,
		const BufferVal &	val
	)

Definition at line 69 of file uda-sample.cc.

References AvgStruct::count, impala_udf::DoubleVal::null(), and AvgStruct::sum.

Referenced by TestAvg().

void AvgInit	(	FunctionContext *	context,
		BufferVal *	val
	)

This is an example of the AVG(double) aggregate function. This function needs to maintain two pieces of state, the current sum and the count. We do this using the BufferVal intermediate type. When this UDA is registered, it would specify 16 bytes (8 byte sum + 8 byte count) as the size for this buffer.

Definition at line 49 of file uda-sample.cc.

Referenced by TestAvg().

void AvgMerge	(	FunctionContext *	context,
		const BufferVal &	src,
		BufferVal *	dst
	)

Definition at line 61 of file uda-sample.cc.

References AvgStruct::count, and AvgStruct::sum.

Referenced by TestAvg().

void AvgUpdate	(	FunctionContext *	context,
		const DoubleVal &	input,
		BufferVal *	val
	)

Definition at line 54 of file uda-sample.cc.

References AvgStruct::count, impala_udf::AnyVal::is_null, AvgStruct::sum, and impala_udf::DoubleVal::val.

Referenced by TestAvg().

BigIntVal CountFinalize	(	FunctionContext *	context,
		const BigIntVal &	val
	)

Definition at line 49 of file uda-test.cc.

Referenced by TEST(), and TestCount().

void CountInit	(	FunctionContext *	context,
		BigIntVal *	val
	)

This is an example of the COUNT aggregate function.

Definition at line 34 of file uda-test.cc.

References impala_udf::AnyVal::is_null, and impala_udf::BigIntVal::val.

Referenced by TEST(), and TestCount().

void CountMerge	(	FunctionContext *	context,
		const BigIntVal &	src,
		BigIntVal *	dst
	)

Definition at line 45 of file uda-test.cc.

References impala_udf::BigIntVal::val.

Referenced by TEST(), and TestCount().

void CountUpdate	(	FunctionContext *	context,
		const IntVal &	input,
		BigIntVal *	val
	)

Definition at line 39 of file uda-test.cc.

References impala_udf::AnyVal::is_null, and impala_udf::BigIntVal::val.

Referenced by TEST(), and TestCount().

StringVal StringConcatFinalize	(	FunctionContext *	context,
		const StringVal &	val
	)

Definition at line 104 of file uda-sample.cc.

Referenced by TestStringConcat().

void StringConcatInit	(	FunctionContext *	context,
		StringVal *	val
	)

This is a sample of implementing the STRING_CONCAT aggregate function. Example: select string_concat(string_col, ",") from table

Definition at line 79 of file uda-sample.cc.

References impala_udf::AnyVal::is_null.

Referenced by TestStringConcat().

void StringConcatMerge	(	FunctionContext *	context,
		const StringVal &	src,
		StringVal *	dst
	)

Definition at line 99 of file uda-sample.cc.

References impala_udf::AnyVal::is_null, and StringConcatUpdate().

Referenced by TestStringConcat().

void StringConcatUpdate	(	FunctionContext *	context,
		const StringVal &	arg1,
		const StringVal &	arg2,
		StringVal *	val
	)

Definition at line 83 of file uda-sample.cc.

References impala_udf::AnyVal::is_null, impala_udf::StringVal::len, and impala_udf::StringVal::ptr.

Referenced by StringConcatMerge(), and TestStringConcat().