add two more benchmarks

Signed-off-by: naivewong <[email protected]>

index/postings.go

@@ -773,26 +773,30 @@ func (it *prefixCompressedPostings) Seek(x uint64) bool {
 	if it.inside && it.key == curKey {
 		// Fast path for x in current block.
 		return it.seekInBlock(x)
-	} else {
-		i := sort.Search(it.numBlock-it.blockIdx, func(i int) bool {
-			off := int(binary.BigEndian.Uint32(it.bs[it.footerAddr+((it.blockIdx+i)<<2):]))
-			k := binary.BigEndian.Uint64(it.bs[off:])
-			return k >= curKey
-		})
-		if i == it.numBlock-it.blockIdx {
-			return false
-		}
-		it.blockIdx += i
-		if i > 0 {
-			it.idx = int(binary.BigEndian.Uint32(it.bs[it.footerAddr+((it.blockIdx)<<2):]))
-		}
+	}
+	i := sort.Search(it.numBlock-it.blockIdx, func(i int) bool {
+		off := int(binary.BigEndian.Uint32(it.bs[it.footerAddr+((it.blockIdx+i)<<2):]))
+		k := binary.BigEndian.Uint64(it.bs[off:])
+		return k >= curKey
+	})
+	if i == it.numBlock-it.blockIdx {
+		return false
+	}
+	it.blockIdx += i
+	if i > 0 {
+		it.idx = int(binary.BigEndian.Uint32(it.bs[it.footerAddr+((it.blockIdx)<<2):]))
 	}
 	it.key = binary.BigEndian.Uint64(it.bs[it.idx:])
 	it.idx += 8
 
 	it.inside = true
 
 	it.nextBlock = int(binary.BigEndian.Uint32(it.bs[it.footerAddr+((it.blockIdx+1)<<2):]))
+	if it.key != curKey {
+		it.cur = it.key | uint64(binary.BigEndian.Uint16(it.bs[it.idx:]))
+		it.idx += 2
+		return true
+	}
 	return it.seekInBlock(x)
 }
 
@@ -834,7 +838,6 @@ func writePrefixCompressedPostings(e *encoding.Encbuf, arr []uint64) {
 		if curKey != key {
 			// Move to next block.
 			if idx != 0 {
-				// We don't need to store the starting offset of the first block because it won't be used.
 				startingOffs = append(startingOffs, uint32(len(e.B)))
 				writePrefixCompressedPostingsBlock(e, vals, key, c)
 				vals = vals[:0]