fix(storage): Fix query cursor read that caused cursor truncation.

Filter cursors buffer points in between calls to Next() if the number
of read points exceeds 1000. Previously, this buffer was being cleared
out before being iterated over which caused queries to return a resultset
which had a number of rows divisable by 1000.

This change moves the clearing of the buffer until after the points have
been read. This change affects any queries which read more than 1000 points
from a single series & have a filter that can be successfully applied to at
least one of those points.

storage/reads/array_cursor.gen.go

@@ -55,8 +55,6 @@ func (c *floatArrayFilterCursor) Next() *cursors.FloatArray {
 
 	if c.tmp.Len() > 0 {
 		a = c.tmp
-		c.tmp.Timestamps = nil
-		c.tmp.Values = nil
 	} else {
 		a = c.FloatArrayCursor.Next()
 	}
@@ -76,6 +74,12 @@ LOOP:
 				}
 			}
 		}
+
+		// Clear bufferred timestamps & values if we make it through a cursor.
+		// The break above will skip this if a cursor is partially read.
+		c.tmp.Timestamps = nil
+		c.tmp.Values = nil
+
 		a = c.FloatArrayCursor.Next()
 	}
 
@@ -271,8 +275,6 @@ func (c *integerArrayFilterCursor) Next() *cursors.IntegerArray {
 
 	if c.tmp.Len() > 0 {
 		a = c.tmp
-		c.tmp.Timestamps = nil
-		c.tmp.Values = nil
 	} else {
 		a = c.IntegerArrayCursor.Next()
 	}
@@ -292,6 +294,12 @@ LOOP:
 				}
 			}
 		}
+
+		// Clear bufferred timestamps & values if we make it through a cursor.
+		// The break above will skip this if a cursor is partially read.
+		c.tmp.Timestamps = nil
+		c.tmp.Values = nil
+
 		a = c.IntegerArrayCursor.Next()
 	}
 
@@ -487,8 +495,6 @@ func (c *unsignedArrayFilterCursor) Next() *cursors.UnsignedArray {
 
 	if c.tmp.Len() > 0 {
 		a = c.tmp
-		c.tmp.Timestamps = nil
-		c.tmp.Values = nil
 	} else {
 		a = c.UnsignedArrayCursor.Next()
 	}
@@ -508,6 +514,12 @@ LOOP:
 				}
 			}
 		}
+
+		// Clear bufferred timestamps & values if we make it through a cursor.
+		// The break above will skip this if a cursor is partially read.
+		c.tmp.Timestamps = nil
+		c.tmp.Values = nil
+
 		a = c.UnsignedArrayCursor.Next()
 	}
 
@@ -703,8 +715,6 @@ func (c *stringArrayFilterCursor) Next() *cursors.StringArray {
 
 	if c.tmp.Len() > 0 {
 		a = c.tmp
-		c.tmp.Timestamps = nil
-		c.tmp.Values = nil
 	} else {
 		a = c.StringArrayCursor.Next()
 	}
@@ -724,6 +734,12 @@ LOOP:
 				}
 			}
 		}
+
+		// Clear bufferred timestamps & values if we make it through a cursor.
+		// The break above will skip this if a cursor is partially read.
+		c.tmp.Timestamps = nil
+		c.tmp.Values = nil
+
 		a = c.StringArrayCursor.Next()
 	}
 
@@ -879,8 +895,6 @@ func (c *booleanArrayFilterCursor) Next() *cursors.BooleanArray {
 
 	if c.tmp.Len() > 0 {
 		a = c.tmp
-		c.tmp.Timestamps = nil
-		c.tmp.Values = nil
 	} else {
 		a = c.BooleanArrayCursor.Next()
 	}
@@ -900,6 +914,12 @@ LOOP:
 				}
 			}
 		}
+
+		// Clear bufferred timestamps & values if we make it through a cursor.
+		// The break above will skip this if a cursor is partially read.
+		c.tmp.Timestamps = nil
+		c.tmp.Values = nil
+
 		a = c.BooleanArrayCursor.Next()
 	}
 

storage/reads/array_cursor.gen.go.tmpl

@@ -54,8 +54,6 @@ func (c *{{$type}}) Next() {{$arrayType}} {
 
 	if c.tmp.Len() > 0 {
 		a = c.tmp
-		c.tmp.Timestamps = nil
-		c.tmp.Values = nil
 	} else {
 		a = c.{{.Name}}ArrayCursor.Next()
 	}
@@ -75,6 +73,12 @@ LOOP:
 				}
 			}
 		}
+		
+		// Clear bufferred timestamps & values if we make it through a cursor.
+		// The break above will skip this if a cursor is partially read.
+		c.tmp.Timestamps = nil
+		c.tmp.Values = nil
+		
 		a = c.{{.Name}}ArrayCursor.Next()
 	}