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https://github.com/mariadb-corporation/mariadb-columnstore-engine.git
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313 lines
11 KiB
C++
313 lines
11 KiB
C++
/* Copyright (C) 2014 InfiniDB, Inc.
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Copyright (c) 2019 MariaDB Corporation
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; version 2 of
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the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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/***********************************************************************
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* $Id$
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*
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*
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***********************************************************************/
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/**
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* MariaDB ColumnStore interface for writing a user defined function (UDF).
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*
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* The basic steps are:
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*
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* 1. add the UDF function interface in udfsdk.h
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* 2. add the UDF function implementation in udfsdk.cpp
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* 3. add the connector stub for this UDF function in udfsdk.cpp
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* 4. build the dynamic library libudfsdk
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* 5. put the library in /usr/local/mariadb/columnstore/lib of all modules
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* 6. restart MariaDB ColumnStore
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* 7. Register the new functions with the commands like:
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*
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* CREATE FUNCTION mcs_add returns REAL soname 'libudfsdk.so';
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* CREATE FUNCTION mcs_isnull returns BOOL soname 'libudfsdk.so';
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*
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* The UDF functions run distributedly in the ColumnStore engine. The evaluation
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* is row by row. Aggregate UDF is currently not supported. Two examples are
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* given in this file to demonstrate the steps that it takes to create a UDF
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* function. More examples can be found in utils/funcexp/func_*.cpp.
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*/
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#include "funcexp.h"
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#include "functor.h"
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#define EXPORT
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namespace udfsdk
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{
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/**
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* UDFSDK interface. Do not make modification here.
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*/
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class UDFSDK
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{
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public:
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EXPORT UDFSDK();
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EXPORT ~UDFSDK();
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EXPORT funcexp::FuncMap UDFMap() const;
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protected:
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private:
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// defaults okay
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// UDFSDK(const UDFSDK& rhs);
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// UDFSDK& operator=(const UDFSDK& rhs);
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};
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/**
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* Example: MCS_add (args1, args2)
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*
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* MCS_add takes two arguments of any data type. It returns a double result.
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*
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* The function interface is defined here. All UDF functions are derived from
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* class funcexp::Func. A set of getXXXval interface APIs are declared in the
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* parent class Func, which will be called by IDB function and expression (F&E)
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* framwork when evaluating the function. Which API to be called depends on
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* the context of the function in the SQL query, i.e., the result type that
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* the function is expected to return.
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*
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* For example, given the following two queries, different APIs will be called
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* to evaluate the function MCS_add.
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*
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* select MCS_add(int1, int2) from t1;
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* getDoubleVal() is called, because the result type of MCS_add is DOUBLE(real).
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*
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* select substr(string1, int1, MCS_add(int1+int2));
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* getIntVal() will be called, because MCS_add() is passed as the third argument
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* to substr function, and an integer result is expected.
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*
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* If one API is not implemented but called for a function, MCS-5001 error will
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* be returned.
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*/
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class MCS_add : public funcexp::Func
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{
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public:
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/*
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* Constructor. Pass the function name to the base constructor.
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*/
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MCS_add() : Func("mcs_add")
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{
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}
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/*
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* Destructor. MCS_add does not need to do anything here to clean up.
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*/
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virtual ~MCS_add()
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{
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}
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/**
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* Decide on the function's operation type
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*
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* Operation type decides which API needs to be called for each function
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* parameter. Sometimes it is obvious. e.g. for function substr (c1, c2, c3),
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* one knows that getStrVal(), getIntVal() and getIntVal() should be called for
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* the three parameters in sequence. In that case, a dummy type can be returned
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* because it won't be used in the function implementation. Sometimes the
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* operation type is decided by the data type of the function parameters.
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* e.g., isnull(c1) function, one should call the corresponding getXXXval()
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* function that in compatible with the result type of c1.
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*
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* @parm fp vector of function parameters
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* Each element is a boost::shared_ptr of execplan::ParseTree. class
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* ParseTree is defined in ~/dbcon/execplan/parsetree.h
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* @parm resultType result type of this function
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* Sometimes it may affect the operation type, but most of the time it
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* can be ignored. Struct ColType is defined in ~/dbcon/execplan/calpontsystemcatalog.h
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* @return operation type for this function
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*
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* This function is called only one from the connector. Once it's determined, it
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* will be passed to the getXXXval() APIs during function evaluation.
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*/
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execplan::CalpontSystemCatalog::ColType operationType(funcexp::FunctionParm& fp,
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execplan::CalpontSystemCatalog::ColType& resultType);
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/**
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* Returns an integer result of this function.
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* All the getXXXvalue APIs take the same arguments. They will be called
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* for every row in the result set when the function is being evaluated.
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* So these functions needs to be efficient.
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*
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* @parm row reference of the current row
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* @parm fp function parameters
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* @parm isNull NULL indicator throughout this function evaluation.
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* the same reference is passed to all the function argument
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* evaluations. One always need to know if any argument is NULL
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* to decide the result of the function. It's explained in detail
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* in MCS_isnull() function example.
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* @parm op_ct the operation type that is determined in operationType().
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*
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*/
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virtual int64_t getIntVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a double result of this function.
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*/
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virtual double getDoubleVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a long double result of this function.
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*/
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virtual long double getLongDoubleVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a float result of this function.
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*/
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virtual float getFloatVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a string result of this function.
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*/
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virtual std::string getStrVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a bool result of this function.
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*/
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virtual bool getBoolVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a decimal result of this function.
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*
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* IDB_Decimal is defined in ~/execplan/treenode.h
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*/
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virtual execplan::IDB_Decimal getDecimalVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns an integer representation of a date result of the function.
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*
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* Check the date/time functions in ~/utils/funcexp for implementation
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* example of this API.
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*/
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virtual int32_t getDateIntVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns an integer representation of a datetime result of the function.
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*
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* Check the date/time functions in ~/utils/funcexp for implementation
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* example of this API.
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*/
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virtual int64_t getDatetimeIntVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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};
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/**
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* Example: MCS_isnull(arg1)
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*
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* The purpose of this example is to demostrate the NULL handling in the UDF interface
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*/
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class MCS_isnull : public funcexp::Func
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{
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public:
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/*
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* Constructor. Pass the function name to the base constructor.
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*/
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MCS_isnull() : Func("mcs_isnull")
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{
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}
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/*
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* Destructor. MCS_add does not need to do anything here to clean up.
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*/
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virtual ~MCS_isnull()
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{
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}
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/**
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* Decide on the function's operation type
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*/
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execplan::CalpontSystemCatalog::ColType operationType(funcexp::FunctionParm& fp,
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execplan::CalpontSystemCatalog::ColType& resultType);
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/**
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* Returns an integer result of this function.
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*/
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virtual int64_t getIntVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a double result of this function.
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*/
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virtual double getDoubleVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a double result of this function.
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*/
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virtual long double getLongDoubleVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a float result of this function.
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*/
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virtual float getFloatVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a string result of this function.
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*/
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virtual std::string getStrVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a bool result of this function.
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*/
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virtual bool getBoolVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns a decimal result of this function.
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*
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* IDB_Decimal is defined in ~/execplan/treenode.h
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*/
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virtual execplan::IDB_Decimal getDecimalVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns an integer representation of a date result of the function.
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*
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* Check the date/time functions in ~/utils/funcexp for implementation
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* example of this API.
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*/
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virtual int32_t getDateIntVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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/**
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* Returns an integer representation of a datetime result of the function.
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*
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* Check the date/time functions in ~/utils/funcexp for implementation
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* example of this API.
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*/
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virtual int64_t getDatetimeIntVal(rowgroup::Row& row, funcexp::FunctionParm& fp, bool& isNull,
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execplan::CalpontSystemCatalog::ColType& op_ct);
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};
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} // namespace udfsdk
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#undef EXPORT
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