When we miss on LoadNextMsg but not starting at first sequence, optim…

…ize jump ahead to not need blk access from file.

Signed-off-by: Derek Collison <[email protected]>

server/filestore.go

@@ -2590,6 +2590,32 @@ func (fs *fileStore) FilteredState(sseq uint64, subj string) SimpleState {
  return ss
 }
 
+// This is used to see if we can selectively jump start blocks based on filter subject and a floor block index.
+// Will return -1 if no matches at all.
+func (fs *fileStore) checkSkipFirstBlock(filter string, wc bool) int {
+ start := uint32(math.MaxUint32)
+ if wc {
+ fs.psim.Match(stringToBytes(filter), func(_ []byte, psi *psi) {
+ if psi.fblk < start {
+ start = psi.fblk
+ }
+ })
+ } else if psi, ok := fs.psim.Find(stringToBytes(filter)); ok {
+ start = psi.fblk
+ }
+ // Nothing found.
+ if start == uint32(math.MaxUint32) {
+ return -1
+ }
+ // Here we need to translate this to index into fs.blks.
+ mb := fs.bim[start]
+ if mb == nil {
+ return -1
+ }
+ bi, _ := fs.selectMsgBlockWithIndex(atomic.LoadUint64(&mb.last.seq))
+ return bi
+}
+
 // Optimized way for getting all num pending matching a filter subject.
 // Lock should be held.
 func (fs *fileStore) numFilteredPending(filter string, ss *SimpleState) {
@@ -6438,16 +6464,15 @@ func (fs *fileStore) LoadNextMsg(filter string, wc bool, start uint64, sm *Store
  // Similar to above if start <= first seq.
  // TODO(dlc) - For v2 track these by filter subject since they will represent filtered consumers.
  if i == bi {
- var ss SimpleState
- fs.numFilteredPendingNoLast(filter, &ss)
+ nbi := fs.checkSkipFirstBlock(filter, wc)
  // Nothing available.
- if ss.Msgs == 0 {
+ if nbi < 0 {
  return nil, fs.state.LastSeq, ErrStoreEOF
  }
  // See if we can jump ahead here.
  // Right now we can only spin on first, so if we have interior sparseness need to favor checking per block fss if loaded.
  // For v2 will track all blocks that have matches for psim.
- if nbi, _ := fs.selectMsgBlockWithIndex(ss.First); nbi > i {
+ if nbi > i {
  i = nbi - 1 // For the iterator condition i++
  }
  }