Add SHOW VSCHEMA KEYSPACES query (#14505)

Signed-off-by: Manan Gupta <[email protected]>

changelog/19.0/19.0.0/summary.md

@@ -6,6 +6,8 @@
   - **[Deprecations and Deletions](#deprecations-and-deletions)**
   - **[Docker](#docker)**
     - [New MySQL Image](#mysql-image)
+  - **[Query Compatibility](#query-compatibility)**
+    - [`SHOW VSCHEMA KEYSPACES` Query](#show-vschema-keyspaces)
 
 ## <a id="major-changes"/>Major Changes
 
@@ -21,3 +23,23 @@ In `v19.0` the Vitess team is shipping a new image: `vitess/mysql`.
 This lightweight image is a replacement of `vitess/lite` to only run `mysqld`.
 
 Several tags are available to let you choose what version of MySQL you want to use: `vitess/mysql:8.0.30`, `vitess/mysql:8.0.34`.
+
+### <a id="query-compatibility"/>Query Compatibility
+
+#### <a id="show-vschema-keyspaces"/>`SHOW VSCHEMA KEYSPACES` Query
+
+A SQL query, `SHOW VSCHEMA KEYSPACES` is now supported in Vitess. This query prints the vschema information
+for all the keyspaces. It is useful for seeing the foreign key mode, whether the keyspace is sharded, and if there is an
+error in the VSchema for the keyspace.
+
+An example output of the query looks like - 
+```sql
+mysql> show vschema keyspaces;
++---------------+---------+------------------+-------+
+| Keyspace Name | Sharded | Foreign Key Mode | Error |
++---------------+---------+------------------+-------+
+| uks           | false   | managed          |       |
+| ks            | true    | managed          |       |
++---------------+---------+------------------+-------+
+2 rows in set (0.00 sec)
+```

go/test/endtoend/vtgate/foreignkey/fk_test.go

@@ -18,6 +18,7 @@ package foreignkey
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"testing"
 	"time"
@@ -907,6 +908,18 @@ func TestFkQueries(t *testing.T) {
 	}
 }
 
+// TestShowVschemaKeyspaces verifies the show vschema keyspaces query output for the keyspaces where the foreign keys are
+func TestShowVschemaKeyspaces(t *testing.T) {
+	mcmp, closer := start(t)
+	conn := mcmp.VtConn
+	defer closer()
+
+	res := utils.Exec(t, conn, "SHOW VSCHEMA KEYSPACES")
+	resStr := fmt.Sprintf("%v", res.Rows)
+	require.Contains(t, resStr, `[VARCHAR("uks") VARCHAR("false") VARCHAR("managed") VARCHAR("")]`)
+	require.Contains(t, resStr, `[VARCHAR("ks") VARCHAR("true") VARCHAR("managed") VARCHAR("")]`)
+}
+
 // TestFkOneCase is for testing a specific set of queries. On the CI this test won't run since we'll keep the queries empty.
 func TestFkOneCase(t *testing.T) {
 	queries := []string{}

go/test/endtoend/vtgate/schematracker/restarttablet/schema_restart_test.go

@@ -129,6 +129,8 @@ func TestVSchemaTrackerInit(t *testing.T) {
 		100*time.Millisecond,
 		60*time.Second,
 		"initial table list not complete")
+
+	utils.AssertMatches(t, conn, "SHOW VSCHEMA KEYSPACES", `[[VARCHAR("ks") VARCHAR("false") VARCHAR("unmanaged") VARCHAR("")]]`)
 }
 
 // TestVSchemaTrackerKeyspaceReInit tests that the vschema tracker

go/test/endtoend/vtgate/schematracker/sharded/st_sharded_test.go

@@ -192,6 +192,12 @@ func TestInitAndUpdate(t *testing.T) {
 		30*time.Second,
 		"initial table list not complete")
 
+	if vtgateVersion >= 19 {
+		utils.AssertMatches(t, conn,
+			"SHOW VSCHEMA KEYSPACES",
+			`[[VARCHAR("ks") VARCHAR("true") VARCHAR("unmanaged") VARCHAR("")]]`)
+	}
+
 	// Init
 	_ = utils.Exec(t, conn, "create table test_sc (id bigint primary key)")
 	expected = `[[VARCHAR("dual")] [VARCHAR("t2")] [VARCHAR("t2_id4_idx")] [VARCHAR("t8")] [VARCHAR("test_sc")]]`

go/vt/sqlparser/ast_funcs.go

@@ -1939,6 +1939,8 @@ func (ty ShowCommandType) ToString() string {
 		return VitessVariablesStr
 	case VschemaTables:
 		return VschemaTablesStr
+	case VschemaKeyspaces:
+		return VschemaKeyspacesStr
 	case VschemaVindexes:
 		return VschemaVindexesStr
 	case Warnings:

go/vt/sqlparser/constants.go

@@ -309,6 +309,7 @@ const (
 	VitessTargetStr            = " vitess_target"
 	VitessVariablesStr         = " vitess_metadata variables"
 	VschemaTablesStr           = " vschema tables"
+	VschemaKeyspacesStr        = " vschema keyspaces"
 	VschemaVindexesStr         = " vschema vindexes"
 	WarningsStr                = " warnings"
 
@@ -881,6 +882,7 @@ const (
 	VitessTarget
 	VitessVariables
 	VschemaTables
+	VschemaKeyspaces
 	VschemaVindexes
 	Warnings
 	Keyspace

go/vt/sqlparser/parse_test.go

@@ -2369,6 +2369,8 @@ var (
 		input: "show vitess_targets",
 	}, {
 		input: "show vschema tables",
+	}, {
+		input: "show vschema keyspaces",
 	}, {
 		input: "show vschema vindexes",
 	}, {