Control document meta store compaction pace.

3 files changed, 18 insertions, 0 deletions

diff --git a/vespalib/src/vespa/vespalib/btree/btreenodestore.h b/vespalib/src/vespa/vespalib/btree/btreenodestore.h
index 0b273b54c3a..81017447580 100644
--- a/vespalib/src/vespa/vespalib/btree/btreenodestore.h
+++ b/vespalib/src/vespa/vespalib/btree/btreenodestore.h
@@ -191,6 +191,10 @@ public:
         return _store.getCompacting(ref);
     }
 
+    bool has_held_buffers() const {
+        return _store.has_held_buffers();
+    }
+    
     template <typename FunctionType>
     void foreach_key(EntryRef ref, FunctionType func) const {
         if (!ref.valid())
diff --git a/vespalib/src/vespa/vespalib/datastore/datastorebase.cpp b/vespalib/src/vespa/vespalib/datastore/datastorebase.cpp
index 2ec8cb3bda3..cce0b0695c2 100644
--- a/vespalib/src/vespa/vespalib/datastore/datastorebase.cpp
+++ b/vespalib/src/vespa/vespalib/datastore/datastorebase.cpp
@@ -66,6 +66,7 @@ public:
           _dsb(dsb),
           _bufferId(bufferId)
     {
+        _dsb.inc_hold_buffer_count();
     }
 
     ~BufferHold() override
@@ -85,6 +86,7 @@ DataStoreBase::DataStoreBase(uint32_t numBuffers, size_t maxArrays)
       _elemHold1List(),
       _elemHold2List(),
       _numBuffers(numBuffers),
+      _hold_buffer_count(0u),
       _maxArrays(maxArrays),
       _compaction_count(0u),
       _genHolder()
@@ -187,6 +189,8 @@ DataStoreBase::transferHoldLists(generation_t generation)
 void
 DataStoreBase::doneHoldBuffer(uint32_t bufferId)
 {
+    assert(_hold_buffer_count > 0);
+    --_hold_buffer_count;
     _states[bufferId].onFree(_buffers[bufferId].getBuffer());
 }
 
@@ -515,5 +519,12 @@ DataStoreBase::startCompactWorstBuffers(bool compactMemory, bool compactAddressS
     return result;
 }
 
+void
+DataStoreBase::inc_hold_buffer_count()
+{
+    assert(_hold_buffer_count < std::numeric_limits<uint32_t>::max());
+    ++_hold_buffer_count;
+}
+
 }
 
diff --git a/vespalib/src/vespa/vespalib/datastore/datastorebase.h b/vespalib/src/vespa/vespalib/datastore/datastorebase.h
index 2617973d239..13c242e85a7 100644
--- a/vespalib/src/vespa/vespalib/datastore/datastorebase.h
+++ b/vespalib/src/vespa/vespalib/datastore/datastorebase.h
@@ -156,6 +156,7 @@ protected:
     ElemHold2List _elemHold2List;
 
     const uint32_t _numBuffers;
+    uint32_t       _hold_buffer_count;
     const size_t   _maxArrays;
     mutable std::atomic<uint64_t> _compaction_count;
 
@@ -350,6 +351,7 @@ private:
      */
     void onActive(uint32_t bufferId, uint32_t typeId, size_t elemsNeeded);
 
+    void inc_hold_buffer_count();
 public:
     uint32_t getTypeId(uint32_t bufferId) const {
         return _buffers[bufferId].getTypeId();
@@ -368,6 +370,7 @@ public:
     std::vector<uint32_t> startCompactWorstBuffers(bool compactMemory, bool compactAddressSpace);
     uint64_t get_compaction_count() const { return _compaction_count.load(std::memory_order_relaxed); }
     void inc_compaction_count() const { ++_compaction_count; }
+    bool has_held_buffers() const noexcept { return _hold_buffer_count != 0u; }
 };
 
 }