[enhancement](merge-on-write) consider version count on size-based cu…

… compaction policy (apache#25352)

be/src/common/config.cpp

@@ -378,6 +378,12 @@ DEFINE_mDouble(compaction_promotion_ratio, "0.05");
 // rowset will be not given to base compaction. The unit is m byte.
 DEFINE_mInt64(compaction_promotion_min_size_mbytes, "128");
 
+// When output rowset of cumulative compaction total version count (end_version - start_version)
+// exceed this config count, the rowset will be moved to base compaction
+// NOTE: this config will work for unique key merge-on-write table only, to reduce version count
+// related cost on delete bitmap more effectively.
+DEFINE_mInt64(compaction_promotion_version_count, "1000");
+
 // The lower bound size to do cumulative compaction. When total disk size of candidate rowsets is less than
 // this size, size_based policy may not do to cumulative compaction. The unit is m byte.
 DEFINE_mInt64(compaction_min_size_mbytes, "64");

be/src/common/config.h

@@ -431,6 +431,12 @@ DECLARE_mDouble(compaction_promotion_ratio);
 // rowset will be not given to base compaction. The unit is m byte.
 DECLARE_mInt64(compaction_promotion_min_size_mbytes);
 
+// When output rowset of cumulative compaction total version count (end_version - start_version)
+// exceed this config count, the rowset will be moved to base compaction
+// NOTE: this config will work for unique key merge-on-write table only, to reduce version count
+// related cost on delete bitmap more effectively.
+DECLARE_mInt64(compaction_promotion_version_count);
+
 // The lower bound size to do cumulative compaction. When total disk size of candidate rowsets is less than
 // this size, size_based policy may not do to cumulative compaction. The unit is m byte.
 DECLARE_mInt64(compaction_min_size_mbytes);

be/src/olap/cumulative_compaction_policy.cpp

@@ -33,10 +33,11 @@ namespace doris {
 
 SizeBasedCumulativeCompactionPolicy::SizeBasedCumulativeCompactionPolicy(
         int64_t promotion_size, double promotion_ratio, int64_t promotion_min_size,
-        int64_t compaction_min_size)
+        int64_t promotion_version_count, int64_t compaction_min_size)
         : _promotion_size(promotion_size),
           _promotion_ratio(promotion_ratio),
           _promotion_min_size(promotion_min_size),
+          _promotion_version_count(promotion_version_count),
           _compaction_min_size(compaction_min_size) {}
 
 void SizeBasedCumulativeCompactionPolicy::calculate_cumulative_point(
@@ -152,6 +153,15 @@ void SizeBasedCumulativeCompactionPolicy::update_cumulative_point(
         size_t total_size = output_rowset->rowset_meta()->total_disk_size();
         if (total_size >= tablet->cumulative_promotion_size()) {
             tablet->set_cumulative_layer_point(output_rowset->end_version() + 1);
+        } else if (tablet->enable_unique_key_merge_on_write() &&
+                   output_rowset->end_version() - output_rowset->start_version() >
+                           _promotion_version_count) {
+            // for MoW table, if there's too many versions, the delete bitmap will grow to
+            // a very big size, which may cause the tablet meta too big and the `save_meta`
+            // operation too slow.
+            // if the rowset should not promotion according to it's disk size, we should also
+            // consider it's version count here.
+            tablet->set_cumulative_layer_point(output_rowset->end_version() + 1);
         }
     }
 }

be/src/olap/cumulative_compaction_policy.h

@@ -114,6 +114,7 @@ class SizeBasedCumulativeCompactionPolicy final : public CumulativeCompactionPol
             int64_t promotion_size = config::compaction_promotion_size_mbytes * 1024 * 1024,
             double promotion_ratio = config::compaction_promotion_ratio,
             int64_t promotion_min_size = config::compaction_promotion_min_size_mbytes * 1024 * 1024,
+            int64_t promotion_version_count = config::compaction_promotion_version_count,
             int64_t compaction_min_size = config::compaction_min_size_mbytes * 1024 * 1024);
 
     /// Destructor function of SizeBasedCumulativeCompactionPolicy.
@@ -169,6 +170,8 @@ class SizeBasedCumulativeCompactionPolicy final : public CumulativeCompactionPol
     double _promotion_ratio;
     /// cumulative compaction promotion min size, unit is byte.
     int64_t _promotion_min_size;
+    // cululative compaction promotion version count, only works for unique key MoW table
+    int64_t _promotion_version_count;
     /// lower bound size to do compaction compaction.
     int64_t _compaction_min_size;
 };