add Merge micro benchmark cases for union merges

Author: mheinzel

bench/micro/Bench/Database/LSMTree/Internal/Merge.hs

@@ -84,23 +84,39 @@ benchmarks = bgroup "Bench.Database.LSMTree.Internal.Merge" [
                          randomWord64OutOf (totalEntries `div` 2)
         , mergeMappend = Just (onDeserialisedValues ((+) @Word64))
         }
+      -- different merge types
     , benchMerge configWord64
-        { name         = "word64-mix-x4"
+        { name         = "word64-mix-collisions-x4-midlevel"
         , nentries     = totalEntries `splitInto` 4
         , finserts     = 1
         , fdeletes     = 1
         , fmupserts    = 1
+        , randomKey    = -- each run uses half of the possible keys
+                         randomWord64OutOf (totalEntries `div` 2)
+        , mergeMappend = Just (onDeserialisedValues ((+) @Word64))
+        , mergeType    = MergeMidLevel
+        }
+    , benchMerge configWord64
+        { name         = "word64-mix-collisions-x4-lastlevel"
+        , nentries     = totalEntries `splitInto` 4
+        , finserts     = 1
+        , fdeletes     = 1
+        , fmupserts    = 1
+        , randomKey    = -- each run uses half of the possible keys
+                         randomWord64OutOf (totalEntries `div` 2)
         , mergeMappend = Just (onDeserialisedValues ((+) @Word64))
+        , mergeType    = MergeLastLevel
         }
     , benchMerge configWord64
-        { name         = "word64-mix-collisions-x4"
+        { name         = "word64-mix-collisions-x4-union"
         , nentries     = totalEntries `splitInto` 4
         , finserts     = 1
         , fdeletes     = 1
         , fmupserts    = 1
         , randomKey    = -- each run uses half of the possible keys
                          randomWord64OutOf (totalEntries `div` 2)
         , mergeMappend = Just (onDeserialisedValues ((+) @Word64))
+        , mergeType    = MergeUnion
         }
       -- not writing anything at all
     , benchMerge configWord64
@@ -174,6 +190,20 @@ benchmarks = bgroup "Bench.Database.LSMTree.Internal.Merge" [
         , fdeletes     = 1
         , mergeType    = MergeLastLevel
         }
+    , benchMerge configUTxOStaking
+        { name         = "utxo-x2-tree-union"  -- binary union merge
+        , nentries     = totalEntries `distributed` [4, 1]
+        , mergeType    = MergeUnion
+        }
+    , benchMerge configUTxOStaking
+        { name         = "utxo-x10-tree-level"  -- merge a whole table (for union)
+        , nentries     = totalEntries `distributed` [ 1, 1, 1
+                                                    , 4, 4, 4
+                                                    , 16, 16, 16
+                                                    , 100  -- last level
+                                                    ]
+        , mergeType    = MergeLastLevel
+        }
     ]
   where
     totalEntries = 50_000
@@ -311,6 +341,14 @@ configUTxO = defaultConfig {
   , randomValue  = first serialiseValue . uniform @_ @UTxOValue
   }
 
+configUTxOStaking :: Config
+configUTxOStaking = defaultConfig {
+    fmupserts    = 1
+  , randomKey    = first serialiseKey . uniform @_ @UTxOKey
+  , randomValue  = first serialiseValue . uniform @_ @Word64
+  , mergeMappend = Just (onDeserialisedValues ((+) @Word64))
+  }
+
 mergeEnv ::
      Config
   -> IO ( FilePath -- ^ Temporary directory