I have a large set of documents in a CouchDB database that were just accidentally bulk deleted using _deleted:true. I also have a backup for this set of data that includes their last known good revision and metadata. I need to maintain the same _id, so simple restore with a new _id is not an option.
Compaction has not been run and I can access any of these documents via the &rev= url parameter as well as their attachments (which are needed).
What I need to do is "restore" these documents to the revision I have on file. Surprisingly, I have come up empty with any queries on how to achieve this. Tips or hacks appreciated.
If you just PUT the whole document, including the attachment stub, back into the DB, with the deleted rev, but less the _deleted:true parameter, then all will be well.
Related
I am looking for a workaround for primary key feature in couchdb. I am saving doc in json format to couchdb externally. Is there any simple way to check if value of a particular field exists?
If you try to save a document that already exists, it will be rejected unless the revision is set to match the existing revision.
Alternately, you can just try to fetch the document, either with GET or HEAD, to check if it exists. See the relevant documentation.
You could perform a mango query previous to the document creation but it will not warranty that another process create a document between the check and the creation.
This post discusses about the same issue:
How to check for duplication before creating a new document in CouchDB/Cloudant?
I have an issue of replication and I need your help in it.In couchDb replication,I want to replicate in such a way that during Couchdb replication I want to reset/update some specific attributes of a a document for some purpose and then these edited documents should be saved in replicated db without effecting the original ones.For example:
A document named Student with attributes id,name,class etc.
And I want to replicate this document in the way that its name and class should be reset/updated.
Will you please tell me how can I achieve it.
Thanks.
You can't update docs during the replication.
But you can exclude docs from being replicated with the help of a CouchDB filter (e.g. preventing all docs with a revision higher then 1 from being replicated).
If you want to have multiple versions of the same dataset (e.g. to have dataset revisions) - i use the term "dataset" instead of "doc" to clearly express that not the internal CouchDB doc revision handling is involved - you have to store them as separated docs that have all a unique id and a reference property like original: "UUID_of_the_original".
you can't use the CouchDB doc revision handling for that purpose (thats what many people think when they see the _rev property in the docs)
I want to delete all documents where foo equals x. Seems like a pretty basic operation, but I just can't figure it out.
I know how to delete an individual document, but that's not good enough - I may have to delete a few thousand at a time.
How do I bulk delete documents in CouchDB?
I don't know if it's the right way but make a view that exposes the foo field, query the view for the doc._ids of all your documents that you want to delete, and make a bulk update against all your documents. So two (ideally) calls to couch.
http://comments.gmane.org/gmane.comp.db.couchdb.user/11222
Has a similar way to go about it.
Do a bulk update on all the documents you want to delete and update doc._deleted=true following the example in Bulk deletion of documents
It's quite easy with bulk delete: https://wiki.apache.org/couchdb/HTTP_Bulk_Document_API
Just POST to _all_docs a list of JSONs that look like:
{"_id": "0", "_rev": "1-62657917", "_deleted": true}
I also needed something to handle that and, since there was nothing at the time, I decided to make my own implementation.
You can find it here.
Update
Since it was very helpful to me and in order to protect myself from mistakes, I added a backup/restore feature to this tool that can now be found on version 0.2
I tried a somewhat long method to delete documents. I first created a view called map_fun that called the documents i wanted to get deleted. I then iterated through the view and stored the keys of allt he documents and used del db['_id'] to delete them
map_fun = function(doc){
if (doc.doc_type == 'classic'){
emit(doc._id, doc)
}}
deldoclist = []
for row in db.query(map_fun):
deldoclist.append(row.key)
for item in deldoclist:
del db[item]
How can I get last created document in couchdb? Maybe some how I can use _changes feature of couchdb? But documentation says, that I only can get list of document, ordered by first created document, ant there is no way to change order.
So how can I get last created document?
You can get the changes feed in descending order as it's also a view.
GET /dbname/_changes?descending=true
You can use limit= as well, so;
GET /dbname/_changes?descending=true&limit=1
will give the latest update.
Your only surefire way to get the last created document is to include a timestamp (created_at or something) with your document. From there, you just need a simple view to output all the docs by their creation date.
I was going to suggest using the last_seq information from the database, but the sequence number changes with every single write, and replication also complicates the matter further.
I have a CouchDB database in production. One of the documents has been edited (in Futon by an other developer).
And it's lost it's ID (don't ask me how he did it).
So now the document's id is an empty string, which makes it impossible to edit or delete via Futon.
Is there a way I could hack into CouchDB to delete that document anyway ?
I couldn't delete the document. But the database itself could be deleted.
And I couldn't reproduce the bug in locale. The other developer says he just removed the _id param and saved. I don't know what happened in CouchDB when he did it. But when I do so, it only recreates a new document (as we'd expect it to do).
So I've been using couch_docs to retrieve the datas locally.
As the id is empty, couch_docs doesn't imports it. So you don't even need to delete it manually.
Then I reimport all the records in an other database. I change the references to the database name in my config and everything works fine.
Destroying the database is not a problem even though there's an empty id.
Technically, a document ID is immutable so actually changing the _id field is not directly possible. Perhaps another document was created as a copy of the first?
A bug in CouchDB 1.1.0 allowed update functions to create empty string IDs.
A similar question asks about this and I gave a walkthrough of deleting empty ids there.
I haven't tried it but LoveSeat is supposed to be able to open and edit couchedb files...
This can be caused (and fixed!) by some error checking CouchDB was missing for _update handlers, as explained in How do you delete a couchdb document with an empty "" document id?