Metha-Cat: Support for Paging?
tobiasschweizer opened this issue · comments
Hi there,
We are using metha-sync to harvest quite a big set. Everything went smoothly and we could create an XML using metha-cat containing the whole set.
The XML is quite big (2.5 GB) and we have some difficulties processing it.
Is there a way to get the records in steps of a limited size (like paging with a defined size and offset) with metha-cat? Setting the from or until params wouldn't help us much I think (libraries might process big batches on a single day).
Thanks a lot!
I ran into similar issues (too big XML files) in the past and I remember that there are tools addressing this problem specifically; one I remember is xml_split.
On debian/ubuntu it seems to be available with the xml-twig-tools package.
$ metha-sync https://yareta.unige.ch/oai && metha-cat https://yareta.unige.ch/oai | xml_split -l 1 -s 50kb
$ ls -l
total 456K
drwxrwxr-x 2 tir tir 4.0K Jun 1 13:29 ./
drwxr-xr-x 39 tir tir 56K Jun 1 13:28 ../
-rw-rw-r-- 1 tir tir 346 Jun 1 13:29 out-00.xml
-rw-rw-r-- 1 tir tir 50K Jun 1 13:29 out-01.xml
-rw-rw-r-- 1 tir tir 54K Jun 1 13:29 out-02.xml
-rw-rw-r-- 1 tir tir 51K Jun 1 13:29 out-03.xml
-rw-rw-r-- 1 tir tir 50K Jun 1 13:29 out-04.xml
-rw-rw-r-- 1 tir tir 51K Jun 1 13:29 out-05.xml
-rw-rw-r-- 1 tir tir 51K Jun 1 13:29 out-06.xml
-rw-rw-r-- 1 tir tir 51K Jun 1 13:29 out-07.xml
-rw-rw-r-- 1 tir tir 23K Jun 1 13:29 out-08.xml
The resulting XML is valid, but slightly modified:
$ xmllint --format out-01.xml 2> /dev/null | head -4
<?xml version="1.0"?>
<xml_split:root xmlns:xml_split="http://xmltwig.com/xml_split">
<record xmlns="http://www.openarchives.org/OAI/2.0/">
<header status="">
Does this help?
PS: Thanks for using metha! I'm just curious (and collecting uses of metha) - if possible, can you share the project name in which metha is used for data acquisition?
@miku Thanks a lot for your answer. We'll try this out!
We are using metha for our linked open research data project Connectome.