Mongodb – How to use mongoexport in count

exportmongodb

I want to get the count of all rows in a single collection into an output file. What is the correct way of doing this

Here is what I did but I am encountering an error.

mongoexport --host 10.1.0.1:27017 --db proddb --collection  UserColl --query "{db.getCollection('UserColl').count()}" --type=csv --out=output.csv

Best Answer

I created a sample.js file like the sample below:

db=db.getSiblingDB('DbName');

printjson( db.getCollection('CollectionName').find().count() );

then I run this script below on cmd:

mongo --host IP:PORT --username username --password password --authenticationDatabase admin --quiet sample.js > sample.csv

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MongoDB Insert Performance

You want to use bulk write operations instead of individual updates and inserts.

// BEFORE your iteration loop
var bulk = db.another_collection.initializeUnorderedBulkOp();

// INSIDE your iteration loop
// instead of db.another_collection.update(…)
bulk.find(query).update(yourUpdateDocumentHere);

// instead of db.another_collection.insert(…)
bulk.insert(yourDocumentToInsertHere);

// AFTER your iteration loop
bulk.execute()

This should speed up the write operations dramatically.

EDIT: as for the bottleneck, extending arrays is a costly operation, since it forces MongoDB to relocate documents often, since the padding will be exceeded. As a rule of thumb: if you have an array which you have to extend often, there is something wrong with your data model. More often than not, it is worth to revise it.

Mongodb – mongoexport not exporting all possible data

I can only speculate without having access to the data, but I suspect that you have non-numeric data in the id field. Try using the $type operator to verify that some of the fields have not been passed in as strings or similar and that all the fields are homogeneous in terms of type.

Best Answer

Related Solutions

MongoDB Insert Performance

Mongodb – mongoexport not exporting all possible data

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