sql: allow old enum value '1' for sql.defaults.vectorize

Fixes: cockroachdb#133278

Release note (bug fix): This commit fixes a bug which causes new
connections to fail with the following error after upgrading to v24.2:

```
ERROR: invalid value for parameter "vectorize": "unknown(1)"
SQLSTATE: 22023
HINT: Available values: off,on,experimental_always
```

In order to hit this bug, the cluster must have:
1. been on version v21.1 at some point in the past
2. run `SET CLUSTER SETTING sql.defaults.vectorize = 'on';` on v21.1
3. not set sql.defaults.vectorize after upgrading past v21.1
4. upgraded all the way to v24.2

The conditions required for this bug can be detected using:

```
SELECT * FROM system.settings WHERE name = 'sql.defaults.vectorize';
```

If the value is '1', the following statement should be run to fix it
before upgrading to v24.2:

```
RESET CLUSTER SETTING sql.defaults.vectorize;
```

This commit fixes the bug by making '1' a legal value for
sql.defaults.vectorize again (mapping to 'on').

pkg/sql/exec_util.go

@@ -587,7 +587,11 @@ var VectorizeClusterMode = settings.RegisterEnumSetting(
 	func() map[sessiondatapb.VectorizeExecMode]string {
 		m := make(map[sessiondatapb.VectorizeExecMode]string, len(sessiondatapb.VectorizeExecMode_name))
 		for k := range sessiondatapb.VectorizeExecMode_name {
-			// Note that VectorizeExecMode.String() remaps "unset" to "on".
+			// Note that for historical reasons, VectorizeExecMode.String() remaps
+			// both "unset" and "201auto" to "on", so we end up with a map like:
+			// 0: on, 1: on, 2: on, 3: experimental_always, 4: off. This means that
+			// after SET CLUSTER SETTING sql.defaults.vectorize = 'on'; we could have
+			// 0, 1, or 2 in system.settings and must handle all three cases as 'on'.
 			m[sessiondatapb.VectorizeExecMode(k)] = sessiondatapb.VectorizeExecMode(k).String()
 		}
 		return m

pkg/sql/logictest/testdata/logic_test/system

@@ -1428,3 +1428,57 @@ ALTER TABLE system.public.tenant_usage CONFIGURE ZONE USING
   num_replicas = 5,
   constraints = '[]',
   lease_preferences = '[]'
+
+# Regression test for 133278, that clusters with sql.defaults.vectorize set to
+# old value '1' can still start new connections.
+
+statement ok
+UPSERT INTO system.settings (name, value, "valueType") VALUES ('sql.defaults.vectorize', '1', 'e')
+
+query TT
+SELECT name, value FROM system.settings WHERE name = 'sql.defaults.vectorize'
+----
+sql.defaults.vectorize  1
+
+query T
+SHOW CLUSTER SETTING sql.defaults.vectorize
+----
+on
+
+statement ok
+SET vectorize = DEFAULT
+
+query T
+SHOW vectorize
+----
+on
+
+# Make sure we can open a new connection.
+user testuser newsession
+
+user root
+
+statement ok
+RESET CLUSTER SETTING sql.defaults.vectorize
+
+statement ok
+RESET vectorize
+
+query TT
+SELECT name, value FROM system.settings WHERE name = 'sql.defaults.vectorize'
+----
+
+query T
+SHOW CLUSTER SETTING sql.defaults.vectorize
+----
+on
+
+query T
+SHOW vectorize
+----
+on
+
+user testuser
+
+statement ok
+RESET vectorize

pkg/sql/sessiondatapb/session_data.go

@@ -50,7 +50,7 @@ func (c DataConversionConfig) GetFloatPrec(typ *types.T) int {
 }
 
 func (m VectorizeExecMode) String() string {
-	if m == VectorizeUnset {
+	if m == VectorizeUnset || m == DeprecatedVectorize201Auto {
 		m = VectorizeOn
 	}
 	name, ok := VectorizeExecMode_name[int32(m)]
@@ -72,6 +72,9 @@ func VectorizeExecModeFromString(val string) (VectorizeExecMode, bool) {
 	if m == VectorizeUnset {
 		return 0, false
 	}
+	if m == DeprecatedVectorize201Auto {
+		m = VectorizeOn
+	}
 	return m, true
 }
 

pkg/sql/sessiondatapb/session_data.proto

@@ -171,7 +171,10 @@ enum VectorizeExecMode {
   // the first enum value as zero is required by proto3. This is mapped to
   // VectorizeOn.
   unset = 0 [(gogoproto.enumvalue_customname) = "VectorizeUnset"];
-  reserved 1;
+  // DeprecatedVectorized201Auto is only possible for clusters that have been
+  // upgraded from v21.1 or older and had the old setting of "201auto" which
+  // was mapped to "on" in v21.1. It is now an alias for "on".
+  deprecated201auto = 1 [(gogoproto.enumvalue_customname) = "DeprecatedVectorize201Auto"];
   // VectorizeOn means that any supported queries will be run using the
   // columnar execution.
   on = 2 [(gogoproto.enumvalue_customname) = "VectorizeOn"];