From 5d405588fcb216563f45077838ebc12547a5e3a2 Mon Sep 17 00:00:00 2001
From: Andrew Hutchings <andrew@linuxjedi.co.uk>
Date: Fri, 2 Jun 2017 14:09:30 +0100
Subject: [PATCH] MCOL-730 Fix decimals in cross engine join

We would get strange values for scale/precision in the results column of
a cross engine join causing bad results. This patch uses the values from
the MariaDB client connector instead.
---
 dbcon/joblist/crossenginestep.cpp | 26 +++++++++++++++++---------
 dbcon/joblist/crossenginestep.h   |  5 ++++-
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/dbcon/joblist/crossenginestep.cpp b/dbcon/joblist/crossenginestep.cpp
index 37ccb0345..88cc6bbd9 100644
--- a/dbcon/joblist/crossenginestep.cpp
+++ b/dbcon/joblist/crossenginestep.cpp
@@ -231,7 +231,7 @@ void CrossEngineStep::makeMappings()
 }
 
 
-void CrossEngineStep::setField(int i, const char* value, unsigned long length, Row& row)
+void CrossEngineStep::setField(int i, const char* value, unsigned long length, MYSQL_FIELD* field, Row& row)
 {
 	CalpontSystemCatalog::ColDataType colType = row.getColType(i);
 
@@ -257,8 +257,16 @@ void CrossEngineStep::setField(int i, const char* value, unsigned long length, R
 		CalpontSystemCatalog::ColType ct;
 		ct.colDataType = colType;
 		ct.colWidth = row.getColumnWidth(i);
-		ct.scale = row.getScale(i);
-		ct.precision = row.getPrecision(i);
+		if (colType == CalpontSystemCatalog::DECIMAL)
+		{
+			ct.scale = field->decimals;
+			ct.precision = field->length;
+		}
+		else
+		{
+            ct.scale = row.getScale(i);
+            ct.precision = row.getPrecision(i);
+		}
 		row.setIntField(convertValueNum(value, ct, row.getSignedNullValue(i)), i);
 	}
 }
@@ -494,7 +502,7 @@ void CrossEngineStep::execute()
 			while ((rowIn = mysql->nextRow()) && !cancelled())
 			{
 				for(int i = 0; i < num_fields; i++)
-					setField(i, rowIn[i], mysql->getFieldLength(i), fRowDelivered);
+					setField(i, rowIn[i], mysql->getFieldLength(i), mysql->getField(i), fRowDelivered);
 
 				addRow(rgDataDelivered);
 			}
@@ -514,7 +522,7 @@ void CrossEngineStep::execute()
 				for(int i = 0; i < num_fields; i++)
 				{
 					if (fFe1Column[i] != -1)
-						setField(fFe1Column[i], rowIn[i], mysql->getFieldLength(i), rowFe1);
+						setField(fFe1Column[i], rowIn[i], mysql->getFieldLength(i), mysql->getField(i), rowFe1);
 				}
 
 				if (fFeFilters && fFeInstance->evaluate(rowFe1, fFeFilters.get()) == false)
@@ -528,7 +536,7 @@ void CrossEngineStep::execute()
 				for(int i = 0; i < num_fields; i++)
 				{
 					if (fFe1Column[i] == -1)
-						setField(i, rowIn[i], mysql->getFieldLength(i), fRowDelivered);
+						setField(i, rowIn[i], mysql->getFieldLength(i), mysql->getField(i), fRowDelivered);
 				}
 
 				addRow(rgDataDelivered);
@@ -546,7 +554,7 @@ void CrossEngineStep::execute()
 			while ((rowIn = mysql->nextRow()) && !cancelled())
 			{
 				for(int i = 0; i < num_fields; i++)
-					setField(i, rowIn[i], mysql->getFieldLength(i), rowFe3);
+					setField(i, rowIn[i], mysql->getFieldLength(i), mysql->getField(i), rowFe3);
 
 				fFeInstance->evaluate(rowFe3, fFeSelects);
 				fFeInstance->evaluate(rowFe3, fFeSelects);
@@ -577,7 +585,7 @@ void CrossEngineStep::execute()
 				for(int i = 0; i < num_fields; i++)
 				{
 					if (fFe1Column[i] != -1)
-						setField(fFe1Column[i], rowIn[i], mysql->getFieldLength(i), rowFe1);
+						setField(fFe1Column[i], rowIn[i], mysql->getFieldLength(i), mysql->getField(i), rowFe1);
 				}
 
 				if (fFeFilters && fFeInstance->evaluate(rowFe1, fFeFilters.get()) == false)
@@ -591,7 +599,7 @@ void CrossEngineStep::execute()
 				for(int i = 0; i < num_fields; i++)
 				{
 					if (fFe1Column[i] == -1)
-						setField(i, rowIn[i], mysql->getFieldLength(i), rowFe3);
+						setField(i, rowIn[i], mysql->getFieldLength(i), mysql->getField(i), rowFe3);
 				}
 
 				fFeInstance->evaluate(rowFe3, fFeSelects);
diff --git a/dbcon/joblist/crossenginestep.h b/dbcon/joblist/crossenginestep.h
index c198efbef..82bb8eda3 100644
--- a/dbcon/joblist/crossenginestep.h
+++ b/dbcon/joblist/crossenginestep.h
@@ -64,14 +64,17 @@ public:
 	{
 		char** row = mysql_fetch_row(fRes);
 		fieldLengths = mysql_fetch_lengths(fRes);
+		fFields = mysql_fetch_fields(fRes);
 		return row;
 	}
 	long getFieldLength(int field) { return fieldLengths[field]; }
+	MYSQL_FIELD* getField(int field) { return &fFields[field]; }
 	const std::string& getError() { return fErrStr; }
 
 private:
 	MYSQL*        fCon;
 	MYSQL_RES*    fRes;
+	MYSQL_FIELD*  fFields;
     std::string             fErrStr;
 	unsigned long *fieldLengths;
 };
@@ -157,7 +160,7 @@ protected:
 	virtual void makeMappings();
 	virtual void addFilterStr(const std::vector<const execplan::Filter*>&, const std::string&);
 	virtual std::string makeQuery();
-	virtual void setField(int, const char*, unsigned long, rowgroup::Row&);
+	virtual void setField(int, const char*, unsigned long, MYSQL_FIELD*, rowgroup::Row&);
 	inline void addRow(rowgroup::RGData &);
 	//inline  void addRow(boost::shared_array<uint8_t>&);
 	virtual int64_t convertValueNum(