Add config option for using B-tree bucket DB in distributor

Still disabled by default; this will be swapped later.
Expose read guard generation for easier debugging.
Add some explicit tests for read guard snapshot semantics.

2 files changed, 17 insertions, 12 deletions

diff --git a/storageserver/src/vespa/storageserver/app/distributorprocess.cpp b/storageserver/src/vespa/storageserver/app/distributorprocess.cpp
index 57fdcdeb248..ff4b2e98cca 100644
--- a/storageserver/src/vespa/storageserver/app/distributorprocess.cpp
+++ b/storageserver/src/vespa/storageserver/app/distributorprocess.cpp
@@ -11,7 +11,8 @@ namespace storage {
 
 DistributorProcess::DistributorProcess(const config::ConfigUri & configUri)
     : Process(configUri),
-      _activeFlag(DistributorNode::NO_NEED_FOR_ACTIVE_STATES)
+      _activeFlag(DistributorNode::NO_NEED_FOR_ACTIVE_STATES),
+      _use_btree_database(false)
 {
 }
 
@@ -29,19 +30,22 @@ DistributorProcess::shutdown()
 void
 DistributorProcess::setupConfig(uint64_t subscribeTimeout)
 {
-    std::unique_ptr<vespa::config::content::core::StorServerConfig> config =
-        config::ConfigGetter<vespa::config::content::core::StorServerConfig>::getConfig(_configUri.getConfigId(), _configUri.getContext(), subscribeTimeout);
-    if (config->persistenceProvider.type
-        != vespa::config::content::core::StorServerConfig::PersistenceProvider::Type::STORAGE)
-    {
+    using vespa::config::content::core::StorServerConfig;
+    using vespa::config::content::core::StorDistributormanagerConfig;
+    using vespa::config::content::core::StorVisitordispatcherConfig;
+
+    auto stor_config = config::ConfigGetter<StorServerConfig>::getConfig(
+            _configUri.getConfigId(), _configUri.getContext(), subscribeTimeout);
+    if (stor_config->persistenceProvider.type != StorServerConfig::PersistenceProvider::Type::STORAGE) {
         _activeFlag = DistributorNode::NEED_ACTIVE_BUCKET_STATES_SET;
     }
+    auto dist_config = config::ConfigGetter<StorDistributormanagerConfig>::getConfig(
+            _configUri.getConfigId(), _configUri.getContext(), subscribeTimeout);
+    _use_btree_database = dist_config->useBtreeDatabase;
     _distributorConfigHandler
-            = _configSubscriber.subscribe<vespa::config::content::core::StorDistributormanagerConfig>(
-                    _configUri.getConfigId(), subscribeTimeout);
+            = _configSubscriber.subscribe<StorDistributormanagerConfig>(_configUri.getConfigId(), subscribeTimeout);
     _visitDispatcherConfigHandler
-            = _configSubscriber.subscribe<vespa::config::content::core::StorVisitordispatcherConfig>(
-                    _configUri.getConfigId(), subscribeTimeout);
+            = _configSubscriber.subscribe<StorVisitordispatcherConfig>(_configUri.getConfigId(), subscribeTimeout);
     Process::setupConfig(subscribeTimeout);
 }
 
@@ -75,7 +79,7 @@ DistributorProcess::configUpdated()
 void
 DistributorProcess::createNode()
 {
-    _node.reset(new DistributorNode(_configUri, _context, *this, _activeFlag, StorageLink::UP()));
+    _node.reset(new DistributorNode(_configUri, _context, *this, _activeFlag, _use_btree_database, StorageLink::UP()));
     _node->handleConfigChange(*_distributorConfigHandler->getConfig());
     _node->handleConfigChange(*_visitDispatcherConfigHandler->getConfig());
 }
diff --git a/storageserver/src/vespa/storageserver/app/distributorprocess.h b/storageserver/src/vespa/storageserver/app/distributorprocess.h
index 0e8d0e2d599..57193f77e42 100644
--- a/storageserver/src/vespa/storageserver/app/distributorprocess.h
+++ b/storageserver/src/vespa/storageserver/app/distributorprocess.h
@@ -15,6 +15,7 @@ namespace storage {
 class DistributorProcess : public Process {
     DistributorNodeContext _context;
     DistributorNode::NeedActiveState _activeFlag;
+    bool _use_btree_database;
     DistributorNode::UP _node;
     config::ConfigHandle<vespa::config::content::core::StorDistributormanagerConfig>::UP
             _distributorConfigHandler;
@@ -23,7 +24,7 @@ class DistributorProcess : public Process {
 
 public:
     DistributorProcess(const config::ConfigUri & configUri);
-    ~DistributorProcess();
+    ~DistributorProcess() override;
 
     void shutdown() override;
     void setupConfig(uint64_t subscribeTimeout) override;