efetch problem

[Krosh]

Using VBA I download fasta file with
http://eutils.ncbi.nlm.nih.gov/entre...re&id=21614549, ..................&rettype=fasta

Problem in that file is not downloaded when I use very long Url with many IDs. Error is "Request URL too large".

On http://www.ncbi.nlm.nih.gov/sites/batchentrez I have no problem with downloading.

[GenoMax]

See the quote from E-utilities help page below. Are you submitting more than 200 UID?

UID list. Either a single UID or a comma-delimited list of UIDs may be provided. All of the UIDs must be from the database specified by db. There is no set maximum for the number of UIDs that can be passed to EFetch, but if more than about 200 UIDs are to be provided, the request should be made using the HTTP POST method.

This link may be useful for creating POST requests: http://stackoverflow.com/questions/4...efox-or-chrome

[Krosh]

Yes, I downloaded more than 200 UIDs and I used HTTP POST method.
Problem not in number of UIDs because I have downloaded for example 500 UIDs but in URL length.

[GenoMax]

According to Wikipedia (link) the limit is

The limit is configurable on Apache2 using the LimitRequestBody directive, which specifies the number of bytes from 0 (meaning unlimited) to 2147483647 (2 GB) that are allowed in a request body.

So if you are running into "request URL too large" then you are likely hitting the limit set by NCBI. I would think that you will have to run multiple queries staying under that limit.