sql: enable comments for virtual views

This commit makes it possible to define hardcoded comments for virtual
views, the same way it was already possible to do so for virtual tables.

Fixes #95427.

Release note: None

pkg/sql/crdb_internal.go

@@ -3697,6 +3697,7 @@ CREATE VIEW crdb_internal.ranges AS SELECT ` +
 		colinfo.RangesExtraRenders +
 		`FROM crdb_internal.ranges_no_leases`,
 	resultColumns: colinfo.Ranges,
+	comment:       "ranges is a view which queries ranges_no_leases for system ranges",
 }
 
 // descriptorsByType is a utility function that iterates through a slice of

pkg/sql/logictest/testdata/logic_test/crdb_internal_catalog

@@ -797,6 +797,7 @@ TableCommentType       4294967235  0  "session variables (RAM)"
 TableCommentType       4294967236  0  "session trace accumulated so far (RAM)"
 TableCommentType       4294967237  0  "ongoing schema changes, across all descriptors accessible by current user (KV scan; expensive!)"
 TableCommentType       4294967238  0  "server parameters, useful to construct connection URLs (RAM, local node only)"
+TableCommentType       4294967239  0  "ranges is a view which queries ranges_no_leases for system ranges"
 TableCommentType       4294967240  0  "range metadata without leaseholder details (KV join; expensive!)"
 TableCommentType       4294967241  0  "defined partitions for all tables/indexes accessible by the current user in the current database (KV scan)"
 TableCommentType       4294967242  0  "per-application transaction statistics (in-memory, not durable; local node only). This table is wiped periodically (by default, at least every two hours)"

pkg/sql/virtual_schema.go

@@ -142,6 +142,9 @@ type virtualSchemaTable struct {
 type virtualSchemaView struct {
 	schema        string
 	resultColumns colinfo.ResultColumns
+
+	// comment represents comment of virtual schema view.
+	comment string
 }
 
 // getSchema is part of the virtualSchemaDef interface.
@@ -366,7 +369,7 @@ func (v virtualSchemaView) initVirtualTableDesc(
 
 // getComment is part of the virtualSchemaDef interface.
 func (v virtualSchemaView) getComment() string {
-	return ""
+	return v.comment
 }
 
 // isUnimplemented is part of the virtualSchemaDef interface.