Merge #132338 #132501 #132563

132338: pgwire: reduce allocations when writing CHAR(N) datums r=mgartner a=mgartner

`ResolveBlankPaddedCharBytes` has been replaced with a more efficient
method of padding `CHAR(N)` datums with trailing spaces.

Epic: None

Release note: None


132501: opt: remove outdated  TODO r=mgartner a=mgartner

A TODO that was addressed in #129007 has been removed.

Release note: None

132563: kvserver: skip empty RACv1 dispatches r=kvoli a=pav-kv

This commit skips creating a `RaftMessageRequest` in the fallback RAC admission dispatch code if there are no pending RACv1 dispatches. Previously, it would send an empty `RaftMessageRequest` which would cause an error in the receiver's `handleRaftRequest`, [message drops](https://github.com/cockroachdb/cockroach/blob/9e12f67ff4ad860651c40dcef489a1556d1d11b7/pkg/kv/kvserver/raft_transport.go#L451-L456), and the receiver's message queue to restart after the following warning:

```
unable to accept Raft message from (n0,s0):?: no handler registered for (n0,s0):?
```

Related to #129508

Co-authored-by: Marcus Gartner <[email protected]>
Co-authored-by: Pavel Kalinnikov <[email protected]>

pkg/kv/kvserver/raft_transport.go

@@ -885,10 +885,12 @@ func (t *RaftTransport) processQueue(
 				dispatchPendingFlowTokensTimer.Reset(0)
 			}
 
-			req := newRaftMessageRequest()
-			maybeAnnotateWithAdmittedRaftLogEntries(req, pendingDispatches)
-			batch.Requests = append(batch.Requests, *req)
-			releaseRaftMessageRequest(req)
+			if len(pendingDispatches) != 0 {
+				req := newRaftMessageRequest()
+				maybeAnnotateWithAdmittedRaftLogEntries(req, pendingDispatches)
+				batch.Requests = append(batch.Requests, *req)
+				releaseRaftMessageRequest(req)
+			}
 
 			maybeAnnotateWithStoreIDs(batch)
 			annotateWithClockTimestamp(batch)

pkg/sql/opt/optbuilder/testdata/scalar

@@ -1664,7 +1664,6 @@ project
       └── filters
            └── NOT ((t:1 >= t:1) AND (t:1 <= CASE NULL WHEN true THEN c:5 ELSE t:1::BPCHAR END))
 
-# TODO(#108360): implicit casts from STRING to CHAR should use bpchar.
 exec-ddl
 CREATE TABLE t108360_1 (t TEXT)
 ----

pkg/sql/pgwire/types.go

@@ -515,15 +515,30 @@ func writeBinaryDecimal(b *writeBuffer, v *apd.Decimal) {
 	}
 }
 
+// spaces is used for padding CHAR(N) datums.
+var spaces = [16]byte{
+	' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
+}
+
 func writeBinaryBytes(b *writeBuffer, v []byte, t *types.T) {
-	v = tree.ResolveBlankPaddedCharBytes(v, t)
 	if t.Oid() == oid.T_char && len(v) == 0 {
 		// Match Postgres and always explicitly include a null byte if we have
 		// an empty string for the "char" type in the binary format.
 		v = []byte{0}
 	}
-	b.putInt32(int32(len(v)))
+	pad := 0
+	if t.Oid() == oid.T_bpchar && len(v) < int(t.Width()) {
+		// Pad spaces on the right of the byte slice to make it of length
+		// specified in the type t.
+		pad = int(t.Width()) - len(v)
+	}
+	b.putInt32(int32(len(v) + pad))
 	b.write(v)
+	for pad > 0 {
+		n := min(pad, len(spaces))
+		b.write(spaces[:n])
+		pad -= n
+	}
 }
 
 func writeBinaryString(b *writeBuffer, v string, t *types.T) {

pkg/sql/pgwire/types_test.go

@@ -504,6 +504,10 @@ func benchmarkWriteColumnarString(b *testing.B, format pgwirebase.FormatCode) {
 	benchmarkWriteColumnar(b, getBatch(types.String), format)
 }
 
+func benchmarkWriteColumnarChar(b *testing.B, format pgwirebase.FormatCode) {
+	benchmarkWriteColumnar(b, getBatch(types.MakeChar(16)), format)
+}
+
 func benchmarkWriteDate(b *testing.B, format pgwirebase.FormatCode) {
 	d, _, err := tree.ParseDDate(nil, "2010-09-28")
 	if err != nil {
@@ -671,6 +675,13 @@ func BenchmarkWriteBinaryColumnarString(b *testing.B) {
 	benchmarkWriteColumnarString(b, pgwirebase.FormatBinary)
 }
 
+func BenchmarkWriteTextColumnarChar(b *testing.B) {
+	benchmarkWriteColumnarChar(b, pgwirebase.FormatText)
+}
+func BenchmarkWriteBinaryColumnarChar(b *testing.B) {
+	benchmarkWriteColumnarChar(b, pgwirebase.FormatBinary)
+}
+
 func BenchmarkWriteTextDate(b *testing.B) {
 	benchmarkWriteDate(b, pgwirebase.FormatText)
 }

pkg/sql/sem/tree/pgwire_encode.go

@@ -32,17 +32,6 @@ func ResolveBlankPaddedChar(s string, t *types.T) string {
 	return s
 }
 
-// ResolveBlankPaddedCharBytes is similar to ResolveBlankPaddedChar but operates
-// on a slice of bytes instead of a string.
-func ResolveBlankPaddedCharBytes(v []byte, t *types.T) []byte {
-	if t.Oid() == oid.T_bpchar && len(v) < int(t.Width()) {
-		// Pad spaces on the right of the byte slice to make it of length
-		// specified in the type t.
-		return append(v, bytes.Repeat([]byte(" "), int(t.Width())-len(v))...)
-	}
-	return v
-}
-
 func (d *DTuple) pgwireFormat(ctx *FmtCtx) {
 	// When converting a tuple to text in "postgres mode" there is
 	// special behavior: values are printed in "postgres mode" then the