vendor: introduces leveldb pick compaction optimization

vendor/github.com/syndtr/goleveldb/leveldb/session_compaction.go

@@ -181,11 +181,15 @@ func (c *compaction) expand() {
 
 	t0, t1 := c.levels[0], c.levels[1]
 	imin, imax := t0.getRange(c.s.icmp)
+
+	// For non-zero levels, the ukey can't hop across tables at all.
+	if c.sourceLevel == 0 {
 		// We expand t0 here just incase ukey hop across tables.
 		t0 = vt0.getOverlaps(t0, c.s.icmp, imin.ukey(), imax.ukey(), c.sourceLevel == 0)
 		if len(t0) != len(c.levels[0]) {
 			imin, imax = t0.getRange(c.s.icmp)
 		}
+	}
 	t1 = vt1.getOverlaps(t1, c.s.icmp, imin.ukey(), imax.ukey(), false)
 	// Get entire range covered by compaction.
 	amin, amax := append(t0, t1...).getRange(c.s.icmp)

vendor/github.com/syndtr/goleveldb/leveldb/table.go

@@ -7,6 +7,7 @@
 package leveldb
 
 import (
+	"bytes"
 	"fmt"
 	"sort"
 	"sync/atomic"
@@ -158,6 +159,22 @@ func (tf tFiles) searchNumLess(num int64) int {
 	})
 }
 
+// Searches smallest index of tables whose its smallest
+// key is after the given key.
+func (tf tFiles) searchMinUkey(icmp *iComparer, umin []byte) int {
+	return sort.Search(len(tf), func(i int) bool {
+		return icmp.ucmp.Compare(tf[i].imin.ukey(), umin) > 0
+	})
+}
+
+// Searches smallest index of tables whose its largest
+// key is after the given key.
+func (tf tFiles) searchMaxUkey(icmp *iComparer, umax []byte) int {
+	return sort.Search(len(tf), func(i int) bool {
+		return icmp.ucmp.Compare(tf[i].imax.ukey(), umax) > 0
+	})
+}
+
 // Returns true if given key range overlaps with one or more
 // tables key range. If unsorted is true then binary search will not be used.
 func (tf tFiles) overlaps(icmp *iComparer, umin, umax []byte, unsorted bool) bool {
@@ -189,6 +206,50 @@ func (tf tFiles) overlaps(icmp *iComparer, umin, umax []byte, unsorted bool) boo
 // expanded.
 // The dst content will be overwritten.
 func (tf tFiles) getOverlaps(dst tFiles, icmp *iComparer, umin, umax []byte, overlapped bool) tFiles {
+	// Short circuit if tf is empty
+	if len(tf) == 0 {
+		return nil
+	}
+	// For non-zero levels, there is no ukey hop across at all.
+	// And what's more, the files in these levels are strictly sorted,
+	// so use binary search instead of heavy traverse.
+	if !overlapped {
+		var begin, end int
+		// Determine the begin index of the overlapped file
+		if umin != nil {
+			index := tf.searchMinUkey(icmp, umin)
+			if index == 0 {
+				begin = 0
+			} else if bytes.Compare(tf[index-1].imax.ukey(), umin) >= 0 {
+				// The min ukey overlaps with the index-1 file, expand it.
+				begin = index - 1
+			} else {
+				begin = index
+			}
+		}
+		// Determine the end index of the overlapped file
+		if umax != nil {
+			index := tf.searchMaxUkey(icmp, umax)
+			if index == len(tf) {
+				end = len(tf)
+			} else if bytes.Compare(tf[index].imin.ukey(), umax) <= 0 {
+				// The max ukey overlaps with the index file, expand it.
+				end = index + 1
+			} else {
+				end = index
+			}
+		} else {
+			end = len(tf)
+		}
+		// Ensure the overlapped file indexes are valid.
+		if begin >= end {
+			return nil
+		}
+		dst = make([]*tFile, end-begin)
+		copy(dst, tf[begin:end])
+		return dst
+	}
+
 	dst = dst[:0]
 	for i := 0; i < len(tf); {
 		t := tf[i]
@@ -201,12 +262,10 @@ func (tf tFiles) getOverlaps(dst tFiles, icmp *iComparer, umin, umax []byte, ove
 			} else if umax != nil && icmp.uCompare(t.imax.ukey(), umax) > 0 {
 				umax = t.imax.ukey()
 				// Restart search if it is overlapped.
-				if overlapped {
 				dst = dst[:0]
 				i = 0
 				continue
 			}
-			}
 
 			dst = append(dst, t)
 		}