From ed151598ffbdcfa5c55798d05d81f100af5303ee Mon Sep 17 00:00:00 2001
From: "Jonathan A. Sternberg" <jonathan@influxdb.com>
Date: Tue, 9 Feb 2016 18:03:44 -0500
Subject: [PATCH] Modify the AuxIterator to include a Start method

The AuxIterator streams points to the underlying iterators. When it
started automatically, race conditions occurred between the stream
closing the iterators and creating iterators from the AuxIterator.
---
 influxql/iterator.gen.go      | 40 +++++++----------------------------
 influxql/iterator.gen.go.tmpl | 10 ++-------
 influxql/iterator.go          | 30 ++++++++++++--------------
 influxql/iterator_test.go     |  1 +
 influxql/select.go            |  2 ++
 5 files changed, 27 insertions(+), 56 deletions(-)

diff --git a/influxql/iterator.gen.go b/influxql/iterator.gen.go
index 2d865f6619..c9b76d67d1 100644
--- a/influxql/iterator.gen.go
+++ b/influxql/iterator.gen.go
@@ -558,18 +558,12 @@ func newFloatAuxIterator(input FloatIterator, seriesKeys SeriesList, opt Iterato
 	itr := &floatAuxIterator{
 		input:  newBufFloatIterator(input),
 		output: make(chan *FloatPoint, 1),
-		fields: newAuxIteratorFields(opt),
+		fields: newAuxIteratorFields(seriesKeys, opt),
 	}
-
-	// Initialize auxiliary fields.
-	if len(opt.Aux) > 0 {
-		itr.fields.init(seriesKeys)
-	}
-
-	go itr.stream()
 	return itr
 }
 
+func (itr *floatAuxIterator) Start()                        { go itr.stream() }
 func (itr *floatAuxIterator) Close() error                  { return itr.input.Close() }
 func (itr *floatAuxIterator) Next() *FloatPoint             { return <-itr.output }
 func (itr *floatAuxIterator) Iterator(name string) Iterator { return itr.fields.iterator(name) }
@@ -1453,18 +1447,12 @@ func newIntegerAuxIterator(input IntegerIterator, seriesKeys SeriesList, opt Ite
 	itr := &integerAuxIterator{
 		input:  newBufIntegerIterator(input),
 		output: make(chan *IntegerPoint, 1),
-		fields: newAuxIteratorFields(opt),
+		fields: newAuxIteratorFields(seriesKeys, opt),
 	}
-
-	// Initialize auxiliary fields.
-	if len(opt.Aux) > 0 {
-		itr.fields.init(seriesKeys)
-	}
-
-	go itr.stream()
 	return itr
 }
 
+func (itr *integerAuxIterator) Start()                        { go itr.stream() }
 func (itr *integerAuxIterator) Close() error                  { return itr.input.Close() }
 func (itr *integerAuxIterator) Next() *IntegerPoint           { return <-itr.output }
 func (itr *integerAuxIterator) Iterator(name string) Iterator { return itr.fields.iterator(name) }
@@ -2348,18 +2336,12 @@ func newStringAuxIterator(input StringIterator, seriesKeys SeriesList, opt Itera
 	itr := &stringAuxIterator{
 		input:  newBufStringIterator(input),
 		output: make(chan *StringPoint, 1),
-		fields: newAuxIteratorFields(opt),
+		fields: newAuxIteratorFields(seriesKeys, opt),
 	}
-
-	// Initialize auxiliary fields.
-	if len(opt.Aux) > 0 {
-		itr.fields.init(seriesKeys)
-	}
-
-	go itr.stream()
 	return itr
 }
 
+func (itr *stringAuxIterator) Start()                        { go itr.stream() }
 func (itr *stringAuxIterator) Close() error                  { return itr.input.Close() }
 func (itr *stringAuxIterator) Next() *StringPoint            { return <-itr.output }
 func (itr *stringAuxIterator) Iterator(name string) Iterator { return itr.fields.iterator(name) }
@@ -3243,18 +3225,12 @@ func newBooleanAuxIterator(input BooleanIterator, seriesKeys SeriesList, opt Ite
 	itr := &booleanAuxIterator{
 		input:  newBufBooleanIterator(input),
 		output: make(chan *BooleanPoint, 1),
-		fields: newAuxIteratorFields(opt),
+		fields: newAuxIteratorFields(seriesKeys, opt),
 	}
-
-	// Initialize auxiliary fields.
-	if len(opt.Aux) > 0 {
-		itr.fields.init(seriesKeys)
-	}
-
-	go itr.stream()
 	return itr
 }
 
+func (itr *booleanAuxIterator) Start()                        { go itr.stream() }
 func (itr *booleanAuxIterator) Close() error                  { return itr.input.Close() }
 func (itr *booleanAuxIterator) Next() *BooleanPoint           { return <-itr.output }
 func (itr *booleanAuxIterator) Iterator(name string) Iterator { return itr.fields.iterator(name) }
diff --git a/influxql/iterator.gen.go.tmpl b/influxql/iterator.gen.go.tmpl
index 6fc3efe0c5..d877388466 100644
--- a/influxql/iterator.gen.go.tmpl
+++ b/influxql/iterator.gen.go.tmpl
@@ -560,18 +560,12 @@ func new{{.Name}}AuxIterator(input {{.Name}}Iterator, seriesKeys SeriesList, opt
 	itr := &{{.name}}AuxIterator{
 		input:  newBuf{{.Name}}Iterator(input),
 		output: make(chan *{{.Name}}Point, 1),
-		fields: newAuxIteratorFields(opt),
+		fields: newAuxIteratorFields(seriesKeys, opt),
 	}
-
-	// Initialize auxiliary fields.
-	if len(opt.Aux) > 0 {
-		itr.fields.init(seriesKeys)
-	}
-
-	go itr.stream()
 	return itr
 }
 
+func (itr *{{.name}}AuxIterator) Start()                        { go itr.stream() }
 func (itr *{{.name}}AuxIterator) Close() error                  { return itr.input.Close() }
 func (itr *{{.name}}AuxIterator) Next() *{{.Name}}Point         { return <-itr.output }
 func (itr *{{.name}}AuxIterator) Iterator(name string) Iterator { return itr.fields.iterator(name) }
diff --git a/influxql/iterator.go b/influxql/iterator.go
index 78c177dd6d..b4ea7afa49 100644
--- a/influxql/iterator.go
+++ b/influxql/iterator.go
@@ -207,6 +207,9 @@ type AuxIterator interface {
 
 	// Auxilary iterator
 	Iterator(name string) Iterator
+
+	// Start starts writing to the created iterators.
+	Start()
 }
 
 // NewAuxIterator returns a new instance of AuxIterator.
@@ -236,10 +239,20 @@ type auxIteratorField struct {
 type auxIteratorFields []*auxIteratorField
 
 // newAuxIteratorFields returns a new instance of auxIteratorFields from a list of field names.
-func newAuxIteratorFields(opt IteratorOptions) auxIteratorFields {
+func newAuxIteratorFields(seriesKeys SeriesList, opt IteratorOptions) auxIteratorFields {
 	fields := make(auxIteratorFields, len(opt.Aux))
 	for i, name := range opt.Aux {
 		fields[i] = &auxIteratorField{name: name, opt: opt}
+		for _, s := range seriesKeys {
+			aux := s.Aux[i]
+			if aux == Unknown {
+				continue
+			}
+
+			if fields[i].typ == Unknown || aux < fields[i].typ {
+				fields[i].typ = aux
+			}
+		}
 	}
 	return fields
 }
@@ -252,21 +265,6 @@ func (a auxIteratorFields) close() {
 	}
 }
 
-// init initializes all auxilary fields with initial points.
-func (a auxIteratorFields) init(seriesKeys SeriesList) {
-	for _, s := range seriesKeys {
-		for i, aux := range s.Aux {
-			if aux == Unknown {
-				continue
-			}
-
-			if a[i].typ == Unknown || aux < a[i].typ {
-				a[i].typ = aux
-			}
-		}
-	}
-}
-
 // iterator creates a new iterator for a named auxilary field.
 func (a auxIteratorFields) iterator(name string) Iterator {
 	for _, f := range a {
diff --git a/influxql/iterator_test.go b/influxql/iterator_test.go
index ef9a1949f7..8dcda80f9f 100644
--- a/influxql/iterator_test.go
+++ b/influxql/iterator_test.go
@@ -611,6 +611,7 @@ func TestFloatAuxIterator(t *testing.T) {
 		},
 		influxql.IteratorOptions{Aux: []string{"f0", "f1"}},
 	)
+	itr.Start()
 
 	itrs := []influxql.Iterator{
 		itr,
diff --git a/influxql/select.go b/influxql/select.go
index 48863ec696..938cf0150a 100644
--- a/influxql/select.go
+++ b/influxql/select.go
@@ -111,6 +111,7 @@ func buildAuxIterators(fields Fields, ic IteratorCreator, opt IteratorOptions) (
 			panic("unreachable")
 		}
 	}
+	aitr.Start()
 
 	// Drain primary aux iterator since there is no reader for it.
 	go drainIterator(aitr)
@@ -168,6 +169,7 @@ func buildFieldIterators(fields Fields, ic IteratorCreator, opt IteratorOptions)
 			}
 			itrs[i] = itr
 		}
+		aitr.Start()
 		return nil
 
 	}(); err != nil {