fix(core): Fix deleteBelowTs rollup issue (#9296)

Author: Harshil Goel

posting/list.go

@@ -507,7 +507,10 @@ type pIterator struct {
 }
 
 func (it *pIterator) seek(l *List, afterUid, deleteBelowTs uint64) error {
-	if deleteBelowTs > 0 && deleteBelowTs <= l.minTs {
+	// Because we store rollup at commitTs + 1, it could happen that a transaction has a startTs = prev commitTs
+	// + 1. Within that transcation if there's a delete all, deleteBelowTs (=startT) would be equal to l.minTs
+	// (rollup timestamp, prev commitTs + 1). So it's allowed deleteBelowTs == l.minTs
+	if deleteBelowTs > 0 && deleteBelowTs < l.minTs {
 		return errors.Errorf("deleteBelowTs (%d) must be greater than the minTs in the list (%d)",
 			deleteBelowTs, l.minTs)
 	}

worker/task.go

@@ -838,8 +838,10 @@ func (qs *queryState) handleUidPostings(
 			}
 
 			if srcFn.fnType == compareAttrFn {
+				pl.RLock()
 				posting.GetStatsHolder().InsertRecord(
 					q.Attr, []byte(srcFn.tokens[i]), uint64(pl.ApproxLen()))
+				pl.RUnlock()
 			}
 
 			switch {
@@ -1831,7 +1833,7 @@ func planForEqFilter(fc *functionContext, pred string, uidlist []uint64) {
 	gotEstimate := false
 	for _, eqToken := range fc.tokens {
 		count := posting.GetStatsHolder().ProcessEqPredicate(pred, []byte(eqToken))
-		if count != math.MaxUint64 {
+		if count != math.MaxUint64 && count != 0 {
 			estimatedCount += count
 			gotEstimate = true
 		} else {