diff --git a/src/lib/PostgresMetaTables.ts b/src/lib/PostgresMetaTables.ts
index d4304645..2c886009 100644
--- a/src/lib/PostgresMetaTables.ts
+++ b/src/lib/PostgresMetaTables.ts
@@ -171,7 +171,13 @@ export default class PostgresMetaTables {
     if (replica_identity === undefined) {
       // skip
     } else if (replica_identity === 'INDEX') {
-      replicaSql = `${alter} REPLICA IDENTITY USING INDEX ${replica_identity_index};`
+      if (replica_identity_index === undefined) {
+        return {
+          data: null,
+          error: { message: 'replica_identity_index is required when replica_identity is INDEX' },
+        }
+      }
+      replicaSql = `${alter} REPLICA IDENTITY USING INDEX ${ident(replica_identity_index)};`
     } else {
       replicaSql = `${alter} REPLICA IDENTITY ${replica_identity};`
     }
diff --git a/test/lib/tables.ts b/test/lib/tables.ts
index 752b9e96..d47693bd 100644
--- a/test/lib/tables.ts
+++ b/test/lib/tables.ts
@@ -454,6 +454,50 @@ test("allow ' in comments", async () => {
   await pgMeta.tables.remove(res.data!.id)
 })
 
+test('replica identity index', async () => {
+  const { data: table } = await pgMeta.tables.create({ name: 't_replica_idx' })
+  await pgMeta.columns.create({
+    table_id: table!.id,
+    name: 'c',
+    type: 'int8',
+    is_nullable: false,
+  })
+  await pgMeta.query('CREATE UNIQUE INDEX "t_replica ""idx""" ON t_replica_idx (c)')
+
+  let res = await pgMeta.tables.update(table!.id, {
+    replica_identity: 'INDEX',
+    replica_identity_index: 't_replica "idx"',
+  })
+  expect(res).toMatchObject({
+    data: { replica_identity: 'INDEX' },
+    error: null,
+  })
+
+  res = await pgMeta.tables.update(table!.id, { replica_identity: 'INDEX' })
+  expect(res).toMatchObject({
+    data: null,
+    error: { message: 'replica_identity_index is required when replica_identity is INDEX' },
+  })
+
+  res = await pgMeta.tables.update(table!.id, {
+    replica_identity: 'INDEX',
+    replica_identity_index: 'nonexistent_idx; DROP TABLE t_replica_idx; --',
+  })
+  expect(res.data).toBeNull()
+  expect(res.error).toMatchObject({
+    message: expect.stringContaining('nonexistent_idx; DROP TABLE t_replica_idx; --'),
+  })
+
+  // The injection payload above must not have dropped the table.
+  res = await pgMeta.tables.retrieve({ id: table!.id })
+  expect(res).toMatchObject({
+    data: { name: 't_replica_idx', replica_identity: 'INDEX' },
+    error: null,
+  })
+
+  await pgMeta.tables.remove(table!.id)
+})
+
 test('primary keys', async () => {
   let res = await pgMeta.tables.create({ name: 't' })
   await pgMeta.columns.create({ table_id: res.data!.id, name: 'c', type: 'int8' })