From 25b8eeb415131419c1125ea8f09a35010914459d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20M=C3=A4kel=C3=A4?= <markus.makela@mariadb.com>
Date: Wed, 22 Apr 2020 09:06:58 +0300
Subject: [PATCH] MXS-2972: Store servers in the cache key

This allows the set of servers used by the service to also participate in
the cache value resolution. This will prevent the most obvious of problems
but any abstractions of the servers will prevent this from working.
---
 .../schemarouter/schemaroutersession.cc       | 19 +++++++++++++++++--
 .../schemarouter/schemaroutersession.hh       |  1 +
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/server/modules/routing/schemarouter/schemaroutersession.cc b/server/modules/routing/schemarouter/schemaroutersession.cc
index 6e3ac02ee..9cc287eb7 100644
--- a/server/modules/routing/schemarouter/schemaroutersession.cc
+++ b/server/modules/routing/schemarouter/schemaroutersession.cc
@@ -45,7 +45,7 @@ SchemaRouterSession::SchemaRouterSession(MXS_SESSION* session,
     , m_backends(backends)
     , m_config(router->m_config)
     , m_router(router)
-    , m_shard(m_router->m_shard_manager.get_shard(m_client->user, m_config->refresh_min_interval))
+    , m_shard(m_router->m_shard_manager.get_shard(get_cache_key(), m_config->refresh_min_interval))
     , m_state(0)
     , m_sent_sescmd(0)
     , m_replied_sescmd(0)
@@ -665,7 +665,7 @@ void SchemaRouterSession::handleError(GWBUF* pMessage,
 void SchemaRouterSession::synchronize_shards()
 {
     m_router->m_stats.shmap_cache_miss++;
-    m_router->m_shard_manager.update_shard(m_shard, m_client->user);
+    m_router->m_shard_manager.update_shard(m_shard, get_cache_key());
 }
 
 /**
@@ -1784,4 +1784,19 @@ SERVER* SchemaRouterSession::get_ps_target(GWBUF* buffer, uint32_t qtype, qc_que
     }
     return rval;
 }
+
+std::string SchemaRouterSession::get_cache_key() const
+{
+    std::string key = m_client->user;
+
+    for (const auto& b : m_backends)
+    {
+        if (b->in_use())
+        {
+            key += b->name();
+        }
+    }
+
+    return key;
+}
 }
diff --git a/server/modules/routing/schemarouter/schemaroutersession.hh b/server/modules/routing/schemarouter/schemaroutersession.hh
index e554591a1..3791884ce 100644
--- a/server/modules/routing/schemarouter/schemaroutersession.hh
+++ b/server/modules/routing/schemarouter/schemaroutersession.hh
@@ -151,6 +151,7 @@ private:
     void                 synchronize_shards();
     void                 handle_mapping_reply(SSRBackend& bref, GWBUF** pPacket);
     bool                 handle_statement(GWBUF* querybuf, SSRBackend& bref, uint8_t command, uint32_t type);
+    std::string          get_cache_key() const;
 
     /** Member variables */
     bool                   m_closed;        /**< True if session closed */