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Questions tagged [wiredtiger]

WiredTiger is a pluggable storage engine for MongoDB 3.0. This tag should only be used for questions surrounding the MongoDB system when used in combination with the WiredTiger storage engine.

MongoDB 3.0 introduces a new pluggable storage engine API and a new storage engine called WiredTiger.

Design goals for WiredTiger, include considerations for heavily threaded hardware, large on-chip caches, and SSD storage.

Latch-free and non-blocking algorithms have been implemented, as well as other techniques that improve scaling, overall throughput and latency.

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MongoDB using too much memory

We've been using MongoDB for several weeks now, the overall trend that we've seen has been that mongodb is using way too much memory (much more than the whole size of its dataset + indexes). I've already read through this question and this question,…
Alireza
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How to restore .wt backup file to local MongoDB?

This is a question that was asked before, but I have tried all solutions, and simply cannot get it right. I have spent quite some time researching before posting this question. I have looked at the official MongoDB documents and many other…
Saketh
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Restore mongoDB by --repair and WiredTiger

We accidentally deleted the directory rm -rf /data/db which was our MongoDB path, and thanks to extundelete, we recovered it and got the directory /data/db. Here are our files in the directory, and the files was generated under MongoDB version…
国贵棠
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MongoDB / WiredTiger: reduce storage size after deleting properties from documents

I use MongoDB 3.4 with WiredTiger storage engine on a replica set of 4 nodes. I shrinked a lot a documents by removing properties that takes most of the space, but the documentation says that this operation doesn't reduce the storage size (only the…
clemp6r
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MongoDB background index builds block secondary

We recently experienced a disruptive incident in a MongoDB 3.2 cluster related to index creation. Scenario: Several indexes were created on the primary using background: true. Indexes were automatically created on the secondary by MongoDB after…
Arjen Meek
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'mongod wiredTiger' on Ubuntu?

I cannot use wiredTiger as a service for MongoDB. I followed this step by step guide; http://docs.mongodb.org/manual/release-notes/3.0-upgrade/ Step-1: Start 3.0 mongod.OK, I did. Step-2: Export the data using mongodump. OK Step-3: Create data…
efkan
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MongoDB Migrating away from RocksDB to WiredTiger

We have been working for some time with RocksDB as our engine and we are now trying to migrate to WiredTiger. We have some pretty big databases around 4~12 TB of data and according to the process described in the docs, we added a new node with…
user164848
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How to copy wt files from another mongo instance?

I received a copy of mongo dbpath directory copy from a peer. I copied entire content to my local dbpath with an intention to work on the collections. However, my local is not recognizing the databases or the collections. Am I missing anything?
Saketh
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Performance impact of having Polymorphic collections in MongoDB?

Say one document(Level 1) is supposed to have N(k) different kinds of items as sub-document arrays(Level 2), and these are stored in a separate collection(s?) due to lack of query optimisation for deep nested array sub docs. Now, we are supposed to…
TarunG
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WiredTiger Page Size

I'm unable to find out if there is a pagesize in a WiredTiger MongoDB storage engine. I mean some analog of the innodb_page_size for MySQL.
Pavel Sapezhko
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Should Azure host write-caching be enabled when using MongoDB's WiredTiger storage engine

I have several virtual machines on Azure running a mongoDB replicaSet with the WiredTiger storage engine. I'm not sure about the proper host caching option to set on the disks that contain the MongoDB data. Azure docs regarding disk caching state…
DamDam
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MongoDB Maxing CPU Usage

I have a weird one here. We have set up our production MongoDB which was populated by our test one so we had something to work off of. As soon as we started the service we hit instant 100% CPU load with nothing running, so we removed the server from…
Jonathan Coffey
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MongoDB responds slowly during the WiredTiger Checkpoint writing process

We have 3 instances of MongoDB 3.2.12 configured as a replica set. Journaling is enabled, the storage engine is WiredTiger. Most of the time our application produces a very low load on the database server and it works well, but rarely we launch a…
RomanG
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WiredTiger prefix compression for index on MongoDB

According to the MongoDB documentation (at least this blog entry https://www.mongodb.com/blog/post/new-compression-options-mongodb-30), prefix compression is enabled by default on MongoDB. However, when I look at one collection, I see…
rudi bruchez
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Is MongoDB secondary index size affected by primary key size?

If I understand correctly, secondary index leaf nodes in MySQL InnoDB engine hold the table primary key value (at least for a unique index). Thus, looking up a value in the secondary index results in two BTREE lookups: one for the secondary index…
nimrodm
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