code: func NewBloomTrieIndexer(db ethdb.Database, odr OdrBackend, parentSize, size uint64) *core.ChainIndexer {
  	trieTable := rawdb.NewTable(db, BloomTrieTablePrefix)
  	backend := &BloomTrieIndexerBackend{
  		diskdb:     db,
  		odr:        odr,
  		trieTable:  trieTable,
  		triedb:     trie.NewDatabaseWithCache(trieTable, 1), // Use a tiny cache only to keep memory down
  		parentSize: parentSize,
  		size:       size,
  	}
  	backend.bloomTrieRatio = size / parentSize
  	backend.sectionHeads = make([]common.Hash, backend.bloomTrieRatio)
  	return core.NewChainIndexer(db, rawdb.NewTable(db, "bltIndex-"), backend, size, 0, time.Millisecond*100, "bloomtrie")
  }
docs: // NewBloomTrieIndexer creates a BloomTrie chain indexer