improve block indexer pruning

indexers/blockindexer/kv/kv.go

@@ -519,6 +519,17 @@ func (idx *BlockerIndexer) indexEvents(batch store.KVBatch, events []abci.Event,
 
 func (idx *BlockerIndexer) Prune(to int64) (uint64, error) {
  eventsPruned := uint64(0)
+
+ batch := idx.store.NewBatch()
+
+ flush := func(batch store.KVBatch, height int64) error {
+ err := batch.Commit()
+ if err != nil {
+ return fmt.Errorf("flush batch to disk: height %d: %w", height, err)
+ }
+ return nil
+ }
+
  for h := int64(1); h < to; h++ {
  key, err := heightKey(h)
  if err != nil {
@@ -531,7 +542,15 @@ func (idx *BlockerIndexer) Prune(to int64) (uint64, error) {
  if err := idx.store.Delete(key); err != nil {
  continue
  }
-
+ eventsPruned++
+ if eventsPruned%1000 == 0 && eventsPruned > 0 {
+ err := flush(batch, h)
+ if err != nil {
+ return 0, err
+ }
+ batch.Discard()
+ batch = idx.store.NewBatch()
+ }
  }
 
  it := idx.store.PrefixIterator([]byte{})
@@ -543,12 +562,24 @@ func (idx *BlockerIndexer) Prune(to int64) (uint64, error) {
  if err != nil || height >= to {
  continue
  }
- err = idx.store.Delete(key)
+ err = batch.Delete(key)
  if err != nil {
  continue
  }
 
  eventsPruned++
+ if eventsPruned%1000 == 0 && eventsPruned > 0 {
+ err := flush(batch, to)
+ if err != nil {
+ return 0, err
+ }
+ batch.Discard()
+ batch = idx.store.NewBatch()
+ }
+ }
+ err := flush(batch, to)
+ if err != nil {
+ return 0, err
  }
 
  return eventsPruned, nil