Fix: truncate must not trigger intermediate commits in streaming trx. (#14759)

jsteemann · mpoeter · web-flow · commit 42ec01c78378 · 2021-09-10T20:58:02.000+02:00
* Fix: truncate must not trigger intermediate commits in streaming trx.

* add CHANGELOG entry

Co-authored-by: mpoeter &lt;manuel@manuel-poeter.at&gt;
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,6 +1,10 @@
 devel
 -----
 
+* Truncate must not trigger intermediate commits while in a streaming
+  transaction, because that would be against the assumption that
+  streaming transactions never do intermediate commits.
+
 * Added ArangoSearch condition optimization: STARTS_WITH is merged 
   with LEVENSHTEIN_MATCH if used in the same AND node and field name and prefix
   matches.
diff --git a/arangod/RocksDBEngine/RocksDBCollection.cpp b/arangod/RocksDBEngine/RocksDBCollection.cpp
@@ -790,12 +790,16 @@ Result RocksDBCollection::truncate(transaction::Methods& trx, OperationOptions&
 
   // avoid OOM error for truncate by committing earlier
   uint64_t const prvICC = state->options().intermediateCommitCount;
-  state->options().intermediateCommitCount = std::min<uint64_t>(prvICC, 10000);
+  if (!state->hasHint(transaction::Hints::Hint::GLOBAL_MANAGED)) {
+    state->options().intermediateCommitCount = std::min<uint64_t>(prvICC, 10000);
+  }
 
   // push our current transaction on the stack
   state->beginQuery(true);
-  auto stateGuard = scopeGuard([state]() noexcept {
+  auto stateGuard = scopeGuard([state, prvICC]() noexcept {
     state->endQuery(true);
+    // reset to previous value after truncate is finished
+    state->options().intermediateCommitCount = prvICC;
   });
 
   uint64_t found = 0;
@@ -844,9 +848,6 @@ Result RocksDBCollection::truncate(transaction::Methods& trx, OperationOptions&
     trackWaitForSync(&trx, options);
   }
 
-  // reset to previous value after truncate is finished
-  state->options().intermediateCommitCount = prvICC;
-
 #ifdef ARANGODB_ENABLE_MAINTAINER_MODE
   if (state->numCommits() == 0) {
     // check IN TRANSACTION if documents have been deleted
