Merge #64760

64760: sql/pgwire: change formatting of floating point infinity values r=rafiss a=iAziz786 Fixes #62601 Postgres drivers such as JDBC rely on infinite values to be formatted as full words in order to be able to parse the value. Release note (sql change): Floating point infinity values are now formatted as `Infinity` (or `-Infinity` if negative). This is for compatibility with Postgres. Co-authored-by: Mohammad Aziz <mdaziz067@gmail.com>
cockroachdb · May 11, 2021 · c3d71fd · c3d71fd
2 parents 8bfaaff + a4a8e23
commit c3d71fd
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Showing 3 changed files with 45 additions and 6 deletions.
diff --git a/pkg/cmd/generate-binary/main.go b/pkg/cmd/generate-binary/main.go
@@ -213,8 +213,8 @@ var inputs = map[string][]string{
 		// float encodings. These deviations are still correct, and it's not worth
 		// special casing them into the code, so they are commented out here.
 		//"NaN",
-		//"Inf",
-		//"-Inf",
+		"Inf",
+		"-Inf",
 		"-000.000",
 		"-0000021234.23246346000000",
 		"-1.2",
@@ -234,8 +234,8 @@ var inputs = map[string][]string{
 		// float encodings. These deviations are still correct, and it's not worth
 		// special casing them into the code, so they are commented out here.
 		//"NaN",
-		//"Inf",
-		//"-Inf",
+		"Inf",
+		"-Inf",
 		"-000.000",
 		"-0000021234.2",
 		"-1.2",

diff --git a/pkg/sql/pgwire/testdata/encodings.json b/pkg/sql/pgwire/testdata/encodings.json
@@ -692,6 +692,20 @@
 		"TextAsBinary": [123, 50, 46, 50, 50, 56, 57, 57, 55, 49, 49, 53, 57, 49, 48, 48, 50, 56, 52, 44, 51, 52, 48, 57, 53, 56, 57, 50, 54, 56, 53, 50, 48, 57, 53, 54, 57, 51, 52, 50, 53, 48, 46, 50, 51, 52, 48, 57, 56, 55, 51, 50, 48, 52, 53, 49, 50, 48, 57, 51, 52, 55, 48, 49, 50, 51, 57, 56, 52, 54, 44, 52, 50, 125],
 		"Binary": [0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 6, 164, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 18, 0, 5, 0, 0, 0, 0, 0, 16, 0, 2, 8, 241, 37, 239, 23, 22, 1, 28, 0, 0, 0, 34, 0, 13, 0, 5, 0, 0, 0, 27, 0, 34, 3, 190, 36, 52, 20, 89, 22, 61, 16, 154, 9, 36, 38, 145, 7, 253, 4, 185, 13, 142, 4, 215, 33, 12, 0, 0, 0, 10, 0, 1, 0, 0, 0, 0, 0, 0, 0, 42]
 	},
+	{
+		"SQL": "'Inf'::float4",
+		"Oid": 700,
+		"Text": "Infinity",
+		"TextAsBinary": [73, 110, 102, 105, 110, 105, 116, 121],
+		"Binary": [127, 128, 0, 0]
+	},
+	{
+		"SQL": "'-Inf'::float4",
+		"Oid": 700,
+		"Text": "-Infinity",
+		"TextAsBinary": [45, 73, 110, 102, 105, 110, 105, 116, 121],
+		"Binary": [255, 128, 0, 0]
+	},
 	{
 		"SQL": "'-000.000'::float4",
 		"Oid": 700,
@@ -755,6 +769,20 @@
 		"TextAsBinary": [49, 46, 52, 48, 49, 51, 101, 45, 52, 53],
 		"Binary": [0, 0, 0, 1]
 	},
+	{
+		"SQL": "'Inf'::float8",
+		"Oid": 701,
+		"Text": "Infinity",
+		"TextAsBinary": [73, 110, 102, 105, 110, 105, 116, 121],
+		"Binary": [127, 240, 0, 0, 0, 0, 0, 0]
+	},
+	{
+		"SQL": "'-Inf'::float8",
+		"Oid": 701,
+		"Text": "-Infinity",
+		"TextAsBinary": [45, 73, 110, 102, 105, 110, 105, 116, 121],
+		"Binary": [255, 240, 0, 0, 0, 0, 0, 0]
+	},
 	{
 		"SQL": "'-000.000'::float8",
 		"Oid": 701,

diff --git a/pkg/sql/pgwire/types.go b/pkg/sql/pgwire/types.go
@@ -98,8 +98,19 @@ func (b *writeBuffer) writeTextDatum(
 		b.write(s)
 
 	case *tree.DFloat:
-		// Start at offset 4 because `putInt32` clobbers the first 4 bytes.
-		s := strconv.AppendFloat(b.putbuf[4:4], float64(*v), 'g', conv.GetFloatPrec(), 64)
+		fl := float64(*v)
+		var s []byte
+		// PostgreSQL supports 'Inf' as a valid literal for the floating point
+		// special value Infinity, therefore handling the special cases for them.
+		// (https://github.com/cockroachdb/cockroach/issues/62601)
+		if math.IsInf(fl, 1) {
+			s = []byte("Infinity")
+		} else if math.IsInf(fl, -1) {
+			s = []byte("-Infinity")
+		} else {
+			// Start at offset 4 because `putInt32` clobbers the first 4 bytes.
+			s = strconv.AppendFloat(b.putbuf[4:4], fl, 'g', conv.GetFloatPrec(), 64)
+		}
 		b.putInt32(int32(len(s)))
 		b.write(s)