From d09ea03b46b72b9481f0d848ce31725ad14252ef Mon Sep 17 00:00:00 2001
From: Oliver Tan <otan@cockroachlabs.com>
Date: Wed, 3 Nov 2021 20:32:55 +1100
Subject: [PATCH] support more extensions

---
 .../sql/bnf/create_extension_stmt.bnf         |  1 +
 docs/generated/sql/bnf/stmt_block.bnf         |  1 +
 pkg/sql/create_extension.go                   |  3 +--
 pkg/sql/parser/sql.y                          |  4 +++
 pkg/sql/pg_catalog.go                         | 25 ++++++++++++++++++-
 5 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/docs/generated/sql/bnf/create_extension_stmt.bnf b/docs/generated/sql/bnf/create_extension_stmt.bnf
index 18affcc235e5..9b42843ecc31 100644
--- a/docs/generated/sql/bnf/create_extension_stmt.bnf
+++ b/docs/generated/sql/bnf/create_extension_stmt.bnf
@@ -1,3 +1,4 @@
 create_extension_stmt ::=
 	'CREATE' 'EXTENSION' 'IF' 'NOT' 'EXISTS' name
+	| 'CREATE' 'EXTENSION' 'IF' 'NOT' 'EXISTS' name 'SCHEMA' name
 	| 'CREATE' 'EXTENSION' name
diff --git a/docs/generated/sql/bnf/stmt_block.bnf b/docs/generated/sql/bnf/stmt_block.bnf
index da806b77f112..19ac445036de 100644
--- a/docs/generated/sql/bnf/stmt_block.bnf
+++ b/docs/generated/sql/bnf/stmt_block.bnf
@@ -472,6 +472,7 @@ create_replication_stream_stmt ::=
 
 create_extension_stmt ::=
 	'CREATE' 'EXTENSION' 'IF' 'NOT' 'EXISTS' name
+	| 'CREATE' 'EXTENSION' 'IF' 'NOT' 'EXISTS' name 'SCHEMA' name
 	| 'CREATE' 'EXTENSION' name
 
 opt_with_clause ::=
diff --git a/pkg/sql/create_extension.go b/pkg/sql/create_extension.go
index e2a821156e50..3c77b4559d11 100644
--- a/pkg/sql/create_extension.go
+++ b/pkg/sql/create_extension.go
@@ -43,7 +43,7 @@ func (n *createExtensionNode) unimplementedExtensionError(issue int) error {
 
 func (n *createExtensionNode) startExec(params runParams) error {
 	switch n.CreateExtension.Name {
-	case "postgis":
+	case "postgis", "pgcrypto":
 		telemetry.Inc(sqltelemetry.CreateExtensionCounter(n.CreateExtension.Name))
 		return nil
 	case "postgis_raster",
@@ -85,7 +85,6 @@ func (n *createExtensionNode) startExec(params runParams) error {
 		"pageinspect",
 		"passwordcheck",
 		"pg_buffercache",
-		"pgcrypto",
 		"pg_freespacemap",
 		"pg_prewarm",
 		"pgrowlocks",
diff --git a/pkg/sql/parser/sql.y b/pkg/sql/parser/sql.y
index 844f79fba8ac..f64a779e56f2 100644
--- a/pkg/sql/parser/sql.y
+++ b/pkg/sql/parser/sql.y
@@ -3478,6 +3478,10 @@ create_extension_stmt:
   {
     $$.val = &tree.CreateExtension{IfNotExists: true, Name: $6}
   }
+| CREATE EXTENSION IF NOT EXISTS name SCHEMA name
+    {
+      $$.val = &tree.CreateExtension{IfNotExists: true, Name: $6}
+    }
 | CREATE EXTENSION name {
     $$.val = &tree.CreateExtension{Name: $3}
   }
diff --git a/pkg/sql/pg_catalog.go b/pkg/sql/pg_catalog.go
index 85c925d7a312..c9e501f6da37 100644
--- a/pkg/sql/pg_catalog.go
+++ b/pkg/sql/pg_catalog.go
@@ -569,7 +569,30 @@ var pgCatalogAvailableExtensionsTable = virtualSchemaTable{
 https://www.postgresql.org/docs/9.6/view-pg-available-extensions.html`,
 	schema: vtable.PGCatalogAvailableExtensions,
 	populate: func(ctx context.Context, p *planner, _ catalog.DatabaseDescriptor, addRow func(...tree.Datum) error) error {
-		// We support no extensions.
+		// We support few extensions.
+		for _, ext := range []struct {
+			name             string
+			defaultVersion   string
+			installedVersion string
+			comment          string
+		}{
+			{name: "postgis", defaultVersion: "3.0.1", installedVersion: "3.0.1", comment: "PostGIS geometry and geography spatial types and functions"},
+			{name: "uuid-ossp", defaultVersion: "1.1", comment: "generate universally unique identifiers (UUIDs)"},
+			{name: "pgcrypto", defaultVersion: "1.3", comment: "cryptographic functions"},
+		} {
+			var installedVersion tree.Datum = tree.DNull
+			if ext.installedVersion != "" {
+				installedVersion = tree.NewDString(ext.installedVersion)
+			}
+			if err := addRow(
+				tree.NewDString(ext.name),
+				tree.NewDString(ext.defaultVersion),
+				installedVersion,
+				tree.NewDString(ext.comment),
+			); err != nil {
+				return err
+			}
+		}
 		return nil
 	},
 	unimplemented: true,