Merge pull request #3019

294adc83 Additional fix for core_tests (Howard Chu)
d52b732e Fix stale readcursor flags (Howard Chu)

src/blockchain_db/lmdb/db_lmdb.cpp

@@ -2623,6 +2623,12 @@ bool BlockchainLMDB::batch_start(uint64_t batch_num_blocks, uint64_t batch_bytes
 
   m_batch_active = true;
   memset(&m_wcursors, 0, sizeof(m_wcursors));
+  if (m_tinfo.get())
+  {
+    if (m_tinfo->m_ti_rflags.m_rf_txn)
+      mdb_txn_reset(m_tinfo->m_ti_rtxn);
+    memset(&m_tinfo->m_ti_rflags, 0, sizeof(m_tinfo->m_ti_rflags));
+  }
 
   LOG_PRINT_L3("batch transaction: begin");
   return true;
@@ -2732,29 +2738,34 @@ void BlockchainLMDB::set_batch_transactions(bool batch_transactions)
 bool BlockchainLMDB::block_rtxn_start(MDB_txn **mtxn, mdb_txn_cursors **mcur) const
 {
   bool ret = false;
+  mdb_threadinfo *tinfo;
   if (m_write_txn && m_writer == boost::this_thread::get_id()) {
     *mtxn = m_write_txn->m_txn;
     *mcur = (mdb_txn_cursors *)&m_wcursors;
     return ret;
   }
-  if (!m_tinfo.get())
+  /* Check for existing info and force reset if env doesn't match -
+   * only happens if env was opened/closed multiple times in same process
+   */
+  if (!(tinfo = m_tinfo.get()) || mdb_txn_env(tinfo->m_ti_rtxn) != m_env)
   {
-    m_tinfo.reset(new mdb_threadinfo);
-    memset(&m_tinfo->m_ti_rcursors, 0, sizeof(m_tinfo->m_ti_rcursors));
-    memset(&m_tinfo->m_ti_rflags, 0, sizeof(m_tinfo->m_ti_rflags));
-    if (auto mdb_res = lmdb_txn_begin(m_env, NULL, MDB_RDONLY, &m_tinfo->m_ti_rtxn))
+    tinfo = new mdb_threadinfo;
+    m_tinfo.reset(tinfo);
+    memset(&tinfo->m_ti_rcursors, 0, sizeof(tinfo->m_ti_rcursors));
+    memset(&tinfo->m_ti_rflags, 0, sizeof(tinfo->m_ti_rflags));
+    if (auto mdb_res = lmdb_txn_begin(m_env, NULL, MDB_RDONLY, &tinfo->m_ti_rtxn))
       throw0(DB_ERROR_TXN_START(lmdb_error("Failed to create a read transaction for the db: ", mdb_res).c_str()));
     ret = true;
-  } else if (!m_tinfo->m_ti_rflags.m_rf_txn)
+  } else if (!tinfo->m_ti_rflags.m_rf_txn)
   {
-    if (auto mdb_res = lmdb_txn_renew(m_tinfo->m_ti_rtxn))
+    if (auto mdb_res = lmdb_txn_renew(tinfo->m_ti_rtxn))
       throw0(DB_ERROR_TXN_START(lmdb_error("Failed to renew a read transaction for the db: ", mdb_res).c_str()));
     ret = true;
   }
   if (ret)
-    m_tinfo->m_ti_rflags.m_rf_txn = true;
-  *mtxn = m_tinfo->m_ti_rtxn;
-  *mcur = &m_tinfo->m_ti_rcursors;
+    tinfo->m_ti_rflags.m_rf_txn = true;
+  *mtxn = tinfo->m_ti_rtxn;
+  *mcur = &tinfo->m_ti_rcursors;
 
   if (ret)
     LOG_PRINT_L3("BlockchainLMDB::" << __func__);
@@ -2772,28 +2783,9 @@ void BlockchainLMDB::block_txn_start(bool readonly)
 {
   if (readonly)
   {
-    bool didit = false;
-    if (m_write_txn && m_writer == boost::this_thread::get_id())
-      return;
-    if (!m_tinfo.get())
-    {
-      m_tinfo.reset(new mdb_threadinfo);
-      memset(&m_tinfo->m_ti_rcursors, 0, sizeof(m_tinfo->m_ti_rcursors));
-      memset(&m_tinfo->m_ti_rflags, 0, sizeof(m_tinfo->m_ti_rflags));
-      if (auto mdb_res = lmdb_txn_begin(m_env, NULL, MDB_RDONLY, &m_tinfo->m_ti_rtxn))
-        throw0(DB_ERROR_TXN_START(lmdb_error("Failed to create a read transaction for the db: ", mdb_res).c_str()));
-      didit = true;
-    } else if (!m_tinfo->m_ti_rflags.m_rf_txn)
-    {
-      if (auto mdb_res = lmdb_txn_renew(m_tinfo->m_ti_rtxn))
-        throw0(DB_ERROR_TXN_START(lmdb_error("Failed to renew a read transaction for the db: ", mdb_res).c_str()));
-      didit = true;
-    }
-    if (didit)
-    {
-      m_tinfo->m_ti_rflags.m_rf_txn = true;
-      LOG_PRINT_L3("BlockchainLMDB::" << __func__ << " RO");
-    }
+    MDB_txn *mtxn;
+	mdb_txn_cursors *mcur;
+	block_rtxn_start(&mtxn, &mcur);
     return;
   }
 
@@ -2818,6 +2810,12 @@ void BlockchainLMDB::block_txn_start(bool readonly)
       throw0(DB_ERROR_TXN_START(lmdb_error("Failed to create a transaction for the db: ", mdb_res).c_str()));
     }
     memset(&m_wcursors, 0, sizeof(m_wcursors));
+    if (m_tinfo.get())
+    {
+      if (m_tinfo->m_ti_rflags.m_rf_txn)
+        mdb_txn_reset(m_tinfo->m_ti_rtxn);
+      memset(&m_tinfo->m_ti_rflags, 0, sizeof(m_tinfo->m_ti_rflags));
+    }
   } else if (m_writer != boost::this_thread::get_id())
     throw0(DB_ERROR_TXN_START((std::string("Attempted to start new write txn when batch txn already exists in ")+__FUNCTION__).c_str()));
 }