I am running a backup on Attachments object using the query:
SELECT Id, IsDeleted, ParentId, Name, IsPrivate, ContentType, BodyLength, OwnerId, CreatedDate, CreatedById, LastModifiedDate, LastModifiedById, SystemModstamp, Description FROM Attachment
However, the application terminates abruptly (due to session timeout) after 4-6 hours. It seems that the SOAP API is processing the response but still I am unable to complete downloading the attachments. Quick prodding through the attachments through the dev console showed that the attachments were about 40GB in total for about 400K records. This wouldn't be possible if I had to download the attachments through a single handler. Therefore, I have decided to chunk the attachments and write the response in parallel. Are there any chunking options available in SOAP API (similar to pk-chunking in Bulk)? What other consequences that I have to prepare apart from session time out, etc.?