From 17c6325e8a6b5bc1489ff7a422a15ec81720efbb Mon Sep 17 00:00:00 2001
From: Yi Wu <yiwu@fb.com>
Date: Fri, 6 Oct 2017 20:53:52 -0700
Subject: [PATCH] WritePrepare Txn: Cancel flush/compaction before destruction

Summary:
On WritePreparedTxnDB destruct there could be running compaction/flush holding a SnapshotChecker, which holds a pointer back to WritePreparedTxnDB. Make sure those jobs finished before destructing WritePreparedTxnDB.

This is caught by TransactionTest::SeqAdvanceTest.
Closes https://github.com/facebook/rocksdb/pull/2982

Differential Revision: D6002957

Pulled By: yiwu-arbug

fbshipit-source-id: f1e70390c9798d1bd7959f5c8e2a1c14100773c3
---
 utilities/transactions/pessimistic_transaction_db.cc | 7 +++++++
 utilities/transactions/pessimistic_transaction_db.h  | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/utilities/transactions/pessimistic_transaction_db.cc b/utilities/transactions/pessimistic_transaction_db.cc
index 4cc2f0915..cf336106a 100644
--- a/utilities/transactions/pessimistic_transaction_db.cc
+++ b/utilities/transactions/pessimistic_transaction_db.cc
@@ -954,5 +954,12 @@ bool WritePreparedTxnDB::MaybeUpdateOldCommitMap(
   return next_is_larger;
 }
 
+WritePreparedTxnDB::~WritePreparedTxnDB() {
+  // At this point there could be running compaction/flush holding a
+  // SnapshotChecker, which holds a pointer back to WritePreparedTxnDB.
+  // Make sure those jobs finished before destructing WritePreparedTxnDB.
+  db_impl_->CancelAllBackgroundWork(true/*wait*/);
+}
+
 }  //  namespace rocksdb
 #endif  // ROCKSDB_LITE
diff --git a/utilities/transactions/pessimistic_transaction_db.h b/utilities/transactions/pessimistic_transaction_db.h
index 9e9d65849..b67d35c03 100644
--- a/utilities/transactions/pessimistic_transaction_db.h
+++ b/utilities/transactions/pessimistic_transaction_db.h
@@ -191,7 +191,7 @@ class WritePreparedTxnDB : public PessimisticTransactionDB {
     Init(txn_db_options);
   }
 
-  virtual ~WritePreparedTxnDB() {}
+  virtual ~WritePreparedTxnDB();
 
   virtual Status Initialize(
       const std::vector<size_t>& compaction_enabled_cf_indices,