Mongodb – How to use –excludeCollectionsWithPrefix in mongodump

mongodbmongodb-3.0

I would like know how to use the option "–excludeCollectionsWithPrefix" of the mongodump ?

I have some collections name with numbers like this:

   registry.logging_event_15313531
   registry.logging_event_143432432
   registry.logging_event_18979865
   registry.logging_event_905998132

I would like remove of mongodump every collection with "registry.logging "

Best Answer

I don't know squat about MongoDB but after reading the docs something like the following is probably what you're looking for:

mongodump  --db test --excludeCollectionsWithPrefix registry.logging

Related Solutions

MongoDB – Backup with mongoexport or mongodump?

As an answer to your first question, both tools (by default) will just walk the _id index to fetch the data and then write it out to disk. So, yes, both tools will similarly impact your working set which is why I would generally recommend running them against a secondary (preferably a hidden secondary if possible). I'll echo Stennie in the comments here and recommend other backup methods if you are dealing with large amounts of data.

For the second question, I assume you are looking for a mongodump equivalent of the --fields option from mongoexport to only dump out specific fields. The query option can be used to filter results, but it cannot be used with a projection (to select the fields returned) - this is a feature request that is being tracked in TOOLS-28 but is not yet scheduled. As Stennie also mentioned, the other option here is to write a custom exporter that fits your needs (and again, I would still recommend running it against a secondary to protect your working set).

Mongodb – Dump first N documents of a collection with mongodump

There is no direct way to limit number of records to export via mongodump; however it is possible indirectly, using the query parameter.

First you need to find last(n) documents you need to export.

Let's say you want to export top 50 documents. First find 50th document _id – if you are finding first(n), then sort ascending order and use $lte operator down in query.

db.col.find({},{_id:1}).sort({_id:-1}).skip(49).limit(1)

Note down the _id value.

Now pass your _id to mongodump and run it from console. (not from mongo shell)

mongodump \
--db <some_db> \
--collection <some_col> \
--query '{_id:{$gte:ObjectId("previously noted _id")}}'

Note: this solution exports the last(n) documents instead of first(n), but it is simple to adapt it.

Best Answer

Related Solutions

MongoDB – Backup with mongoexport or mongodump?

Mongodb – Dump first N documents of a collection with mongodump

Related Question