[Koha] Import staged MARC records with ElasticSearch engine

Hello all, - Importing MARC records into catalog form (Manage staged MARC records) in staff client GUI using ElasticSearch engine is very slow and accidentally stops after importing some hundreds of records, That we may spend 3 days to import about 26000 record only, Is that normal? or there are any other configurations should be done first with ElasticSearch engine? - We are using Koha 16.11.01. Thanks in advance.