Use cursored writes

willcl-ark · Oct 1, 2024 · 137024f · 137024f
1 parent a4900d2
commit 137024f
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Showing 2 changed files with 11 additions and 9 deletions.
diff --git a/src/dbwrapper.cpp b/src/dbwrapper.cpp
@@ -429,7 +429,7 @@ MDBXWrapper::MDBXWrapper(const DBParams& params)
 
     LogPrintf("Opening MDBX in %s\n", fs::PathToString(params.path));
 
-    DBContext().create_params.geometry.pagesize = 16384;
+    DBContext().create_params.geometry.pagesize = 4096;
 
     // We need this because of some unpleasant (for us) passing around of the
     // Chainstate between threads during initialization.
@@ -519,6 +519,7 @@ size_t MDBXWrapper::DynamicMemoryUsage() const
 
 struct MDBXBatch::MDBXWriteBatchImpl {
     mdbx::txn_managed txn;
+    mdbx::cursor_managed cur;
 };
 
 MDBXBatch::MDBXBatch (const CDBWrapperBase& _parent) : CDBBatchBase(_parent)
@@ -527,6 +528,7 @@ MDBXBatch::MDBXBatch (const CDBWrapperBase& _parent) : CDBBatchBase(_parent)
     m_impl_batch = std::make_unique<MDBXWriteBatchImpl>();
 
     m_impl_batch->txn = parent.DBContext().env.start_write();
+    m_impl_batch->cur = m_impl_batch->txn.open_cursor(parent.DBContext().map);
 };
 
 MDBXBatch::~MDBXBatch()
@@ -538,22 +540,22 @@ MDBXBatch::~MDBXBatch()
 
 void MDBXBatch::CommitAndReset()
 {
+    // Committing writes closes cursors
     m_impl_batch->txn.commit();
 
     auto &parent = static_cast<const MDBXWrapper&>(m_parent);
     m_impl_batch->txn = parent.DBContext().env.start_write();
+    m_impl_batch->cur = m_impl_batch->txn.open_cursor(parent.DBContext().map);
 }
 
 void MDBXBatch::WriteImpl(Span<const std::byte> key, DataStream& value)
 {
-    auto &parent = static_cast<const MDBXWrapper&>(m_parent);
-
     mdbx::slice slKey(CharCast(key.data()), key.size());
     value.Xor(m_parent.GetObfuscateKey());
     mdbx::slice slValue(CharCast(value.data()), value.size());
 
     try {
-        m_impl_batch->txn.put(parent.m_db_context->map, slKey, slValue, mdbx::put_mode::upsert);
+        m_impl_batch->cur.upsert(slKey, slValue);
     }
     catch (mdbx::error err) {
         const std::string errmsg = "Fatal MDBX error: " + err.message();
@@ -564,10 +566,8 @@ void MDBXBatch::WriteImpl(Span<const std::byte> key, DataStream& value)
 
 void MDBXBatch::EraseImpl(Span<const std::byte> key)
 {
-    auto &parent = static_cast<const MDBXWrapper&>(m_parent);
-
     mdbx::slice slKey(CharCast(key.data()), key.size());
-    m_impl_batch->txn.erase(parent.m_db_context->map, slKey);
+    m_impl_batch->cur.erase(slKey);
 }
 
 size_t MDBXBatch::SizeEstimate() const

diff --git a/src/txdb.cpp b/src/txdb.cpp
@@ -131,7 +131,7 @@ bool CCoinsViewDB::BatchWrite(CoinsViewCacheCursor& cursor, const uint256 &hashB
         // since any size we choose that is a multiple of the page size
         // we will end up committing before we hit the maximum number of
         // writes at that page size.
-        if (batch.SizeEstimate() >= 4*m_options.batch_write_bytes) {
+        if (changed % 262144 == 0) {
             LogDebug(BCLog::COINDB, "Writing partial batch of %.2f MiB\n", batch.SizeEstimate() * (1.0 / 1048576.0));
             m_db->WriteBatch(batch);
         }
@@ -142,7 +142,9 @@ bool CCoinsViewDB::BatchWrite(CoinsViewCacheCursor& cursor, const uint256 &hashB
     batch.Write(DB_BEST_BLOCK, hashBlock);
 
     LogDebug(BCLog::COINDB, "Writing final batch of %.2f MiB\n", batch.SizeEstimate() * (1.0 / 1048576.0));
-    bool ret = m_db->WriteBatch(batch);
+
+    // We need to force a sync on the final write.
+    bool ret = m_db->WriteBatch(batch, true);
     LogDebug(BCLog::COINDB, "Committed %u changed transaction outputs (out of %u) to coin database...\n", (unsigned int)changed, (unsigned int)count);
     return ret;
 }