Add expendRatioM to extend M to cover more items in one table.

This is for un-even distribution hash, some entries may
have more items than the others, this expending makes
those items in same range table, so that we have less
opportunity to access overflow region.
Signed-off-by: NDoMyJob <46307927+DoMyJob@users.noreply.github.com>

opt/options.go

@@ -163,24 +163,11 @@ func FinalizeConfig(config *Options) (*Options, error) {
 
 	// calc M, N, D
 	c, d, n, m := config.TotalVolumn, (uint64)(config.DataBlockSize), (uint64)(config.IndexTableRows), (uint64)(config.IndexTableCols)
-	// range len array: N size array of uint16, i.e. [uint16, uint16, ...(N)]
-	// rangeLenSize := (uint64)(unsafe.Sizeof((uint16)(0)))
-	// index table item [Hash (32bytes) | OffsetIdx (uint32)]
-	// indexTableEntrySize := (uint64)(unsafe.Sizeof(common.Hash{})) + (uint64)(unsafe.Sizeof((uint32)(0)))
-
-	// Total disk allocation:
-	// --------+-------------------+-----------------------------+------------+----------------+
-	// [Header]|[ RangeTableSizes ]|[         HashTable         ]|[    Data  ]|[     BitMap    ]
-	// --------+-------------------+-----------------------------+------------+----------------+
-	// h       + rangeLenSize * n  + indexTableEntrySize* n * m  + n * d * m  + (m * n + 7)/ 8
-	// --------+-------------------+-----------------------------+------------+----------------+
 	m = c / (n * d)
 	if m < 4 || m >= MaxRangeCoverage {
-		// m can not == MAX_RANGE_COVERAGE because max uint16 is (MAX_RANGE_COVERAGE - 1)
-		// otherwise we shoud keep +1 in mind when calc the index table size, which seems a little bit tricky.
 		return nil, ErrConfigM
 	}
-	config.IndexTableCols = (uint32)(m)
+	config.IndexTableCols = uint32((float32)(m) * expendRatioM)
 
 	if config.IndexTableRows > MaxRangeNumber || !ytfs.IsPowerOfTwo((uint64)(config.IndexTableRows)) {
 		return nil, ErrConfigN

opt/property.go

@@ -2,5 +2,6 @@ package opt
 
 // properties for internal use.
 const (
-	DebugPrint bool = true
+	DebugPrint bool = false
+	expendRatioM float32 = 1.2
 )