How to execute a js file in MongoDB

Question: I have a js file - which iterates through some MongoDB collections - and currently I execute on an adhoc basis using the mongo shell. I now need to schedule this process on a regular basis and researching some effective methods to use? Can you supply some examples \ methods to deploy Answer: I use two main methods to execute external js files . The first method utilises mongo shell & the second method use the MongoDB load function. Using this method gives you flexibility to trigger steps with a scheduler such as Crontab Method 1 : Using the... Read more →

How to use MongoDB column alias in SQL Server SELECT

Question: I am accessing data through a SQL Server Linked Server . The Linked Server is interfacing a MongoDB ODBC - connected to a MongoDB. The MongoDB ODBC connects to the BI Connector - which in turn extracts some collections. When the results are returned using the SQL Server OPENQUERY functionality , the dot nation is used to represent some columns. I want the columns presented without dot notation. How can I return an alias? Answer: When using OPENQUERY command through SQL Server connecting to MongoDB - it will present with dot notation. For Example: select * from OPENQUERY(MongoDB_TEST,'select *... Read more →

How to restore a single MongoDB database from a Snapshot Backup

Get the MongoDB snapshot archival download link You will need to obtain this link from the MongoDB Operations Manager. (There is an alternative option to scp the .tar.gz file ).From the Continuous Backup section section obtain the download link Log onto the server and download the file using using curl. ----curl is a useful tool to download the tar file curl download_url --output myfile.tar.gz ----unpack the tar file tar -xvf myfile.tar.gz ----the temp-database-path should be accessible by mongod ----e.g of creating the the temp-database-path mkdir temp-database-path chown mongod:mongod temp-database-path mv Start a new, temporary MongoDB process on a... Read more →

How to use mongodrdrl to extract a MongoDB collection schema

mongodrdl : what is it ? It is a tool packaged with MongoDB BI Connector. It has a number of functions to assist is mapping and manipulating schemas. How can I use mongodrdl? This is an example of a mongodrdl command line request. In this example the mongodrdl command line tool samples the namespaces of the database and collection specified. For more options check the official MongoDB BI Connector documentation mongodrdl sample --host "myserver" --port 27017 --authenticationDatabase admin --username myAdmin --password myPw1 --db db1 --collection mycollection --out myCollection.drdl This is a snippet from the file output schema: - db: myDB... Read more →

Announcing Powerful Rules for Disruptors with MongoDB

An interesting presentation highlighting the power of keeping the pressure on but making as many friends as possible - to create change . Modernizing and rethinking legacy platforms can be a daunting task. This presentation describes cultural buttons to push - and how to start small , but keep growing. Starting small - allows developing expertise at a granular level which is the foundation of hyperscale These are some highlights from the presentation- with a link to the presentation Rules for Disruptors - Making, Managing and Scaling the Case for Change with MongoDB by Jeff Needham - Architect The most... Read more →

MongoDB 4.2.7 Bug - Off-by-one overflow in block-modification bitmaps for incremental backup

A bug on MongoDB 4.2.7 has been identified- and a fix is included in 4.2.8 .Certain conditions are required for the bug to appear - detailed below. Based on the supporting documentation for the MongoDB 4.2.7 bug to occur: Must be running MongoDB 4.2.7. Managed by Ops Manager 4.2.13+ or managed in Cloud Manager with MongoDB agent version v10.14.0+. Incremental backups are enabled. The DB server has collection files greater than 2GB on disk. These collections are modified anytime after backups are enabled. If these conditions are met , there is a possibility that MongoDB will improperly overwrite memory. Read... Read more →

Failed: error dumping users and roles: error writing data for collection with mongodump

Question: I've started the a MongoDB migration using the mongodump module, but when executing the command : mongodump --username="my_un" --password="my_pw" I receive the following error message. Failed: error dumping users and roles: error writing data for collection `admin.system.users` to disk: error reading collection: Failed to parse: { find: "system.users", skip: 0, snapshot: true, $readPreference: { mode: "secondaryPreferred" }, $db: "admin" }. Unrecognized field 'snapshot'. I've executed the same command on other installations with no issues? Is there quick fix for this error message? Answer: I've seen this error before and can be related to the default usage of _id during... Read more →

Overcome the MongoDB Backup is down alert

I've set up a new MongoDB single node replicaset using MongoDB 4.2.x. Although I'm using the same server and agents configuration settings as other replicasets in the same deployment - there is a regular MongoDB alert being triggered. Backup is down Backup Agent Alert Details CREATED 2020/05/29 13:12 GMT DATA-BEARING HOSTS (INSTALL AGENT ON AT LEAST ONE) rsdevelop (at least one of the following mongod(s) needs a co-located agent: [muserver.xxxxx.net:27017]) OPEN The scheduled backups are being completed , and there aren't any errors. Why is the Backup is down alert being triggered? I checked through the MongoDB documentation and the... Read more →

How to migrate databases with mongodump and mongorestore

For small deployments , the MongoDB utilities mongodump and mongorestore is an efficient and useful method. The steps below outline how to take a backup of the MongoDB databases on server1 and migrate\restore onto server2 The mongodump utility can create a backup for a server, individual databases or collection(s), or a customised query for a collection subset. In this example - I'm taking a mongodump of all the user databases including admin on MongoDB - server1. I'm using a logon account with sufficient privileges , that has at least backupadmin privileges Step 1 - This command backups all the databases... Read more →

How to edit a user password with MongoDB Ops Manager

Question: I have a list of MongoDB Users refreshed and appearing in the Deployment | MongoDB Users Screen. These were all users created directly on the MongoDB server outside of the MongoDB Ops Manager. When the users were refreshed the Synched status is set at No. What I'm trying to do is change the password for the user via the MongoDB Ops Manager - but without having to do it at the MongoDB server. The user is created in 3 replica sets - and I'd like to maintain the same password in all the 3 replicasets. Is it possible to... Read more →