Improve startup error logging (#15846)

jsteemann · KVS85 · web-flow · commit 5a1026a00b77 · 2022-03-04T15:38:33.000+03:00
* Improve startup error logging

* Log a better startup error in case an ArangoDB 3.7 is started on a too new
  database directory (3.9 or higher).

* update CHANGELOG

* Update CHANGELOG

Co-authored-by: Vadim &lt;vadim@arangodb.com&gt;
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,6 +1,9 @@
 v3.8.6 (2022-02-16)
 -------------------
 
+* Log a better startup error in case an ArangoDB 3.8 is started on a too new
+  database directory (3.9 or higher).
+
 * Harden validator for binary VelocyPack against additional types of malicious
   inputs.
 
diff --git a/arangod/RocksDBEngine/RocksDBEngine.cpp b/arangod/RocksDBEngine/RocksDBEngine.cpp
@@ -36,6 +36,7 @@
 #include "Basics/WriteLocker.h"
 #include "Basics/application-exit.h"
 #include "Basics/build.h"
+#include "Basics/exitcodes.h"
 #include "Basics/files.h"
 #include "Basics/system-functions.h"
 #include "Cache/CacheManagerFeature.h"
@@ -871,6 +872,26 @@ void RocksDBEngine::start() {
                "re-import data";
         FATAL_ERROR_EXIT();
       }
+     
+      // check if we have too many column families, namely some known ones
+      // from future versions of ArangoDB
+      if (existingColumnFamilies.size() > numberOfColumnFamilies) {
+        for (auto const& it : existingColumnFamilies) {
+          if (it == "ZkdIndex" || it == "ReplicatedLogs") {
+            // introduced in 3.9 or 3.10
+            LOG_TOPIC("1bdd3", ERR, Logger::STARTUP) 
+              << "Unknown column family found in RocksDB database: " << it;
+          }
+        }
+        
+        LOG_TOPIC("c91a4", ERR, Logger::STARTUP)
+            << "Database version check failed: "
+            << "the database directory seems to be from a future ArangoDB version. "
+            << "This is unsupported!";
+        // let's continue, because maybe the database starts anyway for some
+        // magic reasons...
+        // FATAL_ERROR_EXIT_CODE(TRI_EXIT_VERSION_CHECK_FAILED);
+      }
     }
   }
 
