sql: code generation for missing pg catalog tables

Previously, programmer had to add missing table manually,
This was inadequate because postgress added a lot of tables and
manual process can lead to coding mistakes or gaps
To address this, diff tool now have the hability to generate the
missing code

Release note: None

Fixes #58001

Release justification: non-production code changes

pkg/sql/BUILD.bazel

@@ -610,6 +610,7 @@ go_test(
         "@com_github_jackc_pgx//pgtype",
         "@com_github_jackc_pgx_v4//:pgx",
         "@com_github_lib_pq//:pq",
+        "@com_github_lib_pq//oid",
         "@com_github_pmezard_go_difflib//difflib",
         "@com_github_stretchr_testify//assert",
         "@com_github_stretchr_testify//require",

pkg/sql/pg_metadata_diff.go

@@ -17,6 +17,9 @@ import (
 	"encoding/json"
 	"io"
 	"os"
+
+	"github.com/cockroachdb/cockroach/pkg/sql/types"
+	"github.com/lib/pq/oid"
 )
 
 // GetPGMetadataSQL is a query uses udt_name::regtype instead of data_type column because
@@ -187,7 +190,8 @@ func (p PGMetadataTables) rewriteDiffs(diffFile string) error {
 	return nil
 }
 
-// Save have the purpose of storing all the data retrieved from postgres and useful information as postgres version
+// Save have the purpose of storing all the data retrieved from postgres and
+// useful information as postgres version.
 func (f *PGMetadataFile) Save(writer io.Writer) {
 	byteArray, err := json.MarshalIndent(f, "", "  ")
 	if err != nil {
@@ -198,3 +202,27 @@ func (f *PGMetadataFile) Save(writer io.Writer) {
 		panic(err)
 	}
 }
+
+//getUnimplementedTables retrieves the tables that are not yet part of CRDB.
+func (p PGMetadataTables) getUnimplementedTables(source PGMetadataTables) PGMetadataTables {
+	notImplemented := make(PGMetadataTables)
+	for tableName := range p {
+		if len(p[tableName]) == 0 && len(source[tableName].getUnimplementedTypes()) == 0 {
+			notImplemented[tableName] = source[tableName]
+		}
+	}
+	return notImplemented
+}
+
+// getUnimplementedTypes verifies that all the types are implemented in cockroach db.
+func (c PGMetadataColumns) getUnimplementedTypes() map[oid.Oid]string {
+	unimplemented := make(map[oid.Oid]string)
+	for _, column := range c {
+		typeOid := oid.Oid(column.Oid)
+		if _, ok := types.OidToType[typeOid]; !ok || typeOid == oid.T_anyarray {
+			unimplemented[typeOid] = column.DataType
+		}
+	}
+
+	return unimplemented
+}