mongodb storage engine mmapv1 vs wiredtiger - Wikitechy https://www.wikitechy.com/interview-questions/tag/mongodb-storage-engine-mmapv1-vs-wiredtiger/ Interview Questions Sat, 16 Apr 2022 06:49:48 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png mongodb storage engine mmapv1 vs wiredtiger - Wikitechy https://www.wikitechy.com/interview-questions/tag/mongodb-storage-engine-mmapv1-vs-wiredtiger/ 32 32 What are the storage engines used by MongoDB ? https://www.wikitechy.com/interview-questions/mongodb/what-are-the-storage-engines-used-by-mongodb/ https://www.wikitechy.com/interview-questions/mongodb/what-are-the-storage-engines-used-by-mongodb/#respond Sat, 16 Apr 2022 06:49:48 +0000 https://www.wikitechy.com/interview-questions/?p=4134
  • Storage engine is responsible for managing how data is stored, both in memory and on disk. It is the component of the database.
  • MongoDB supports multiple storage engines, as different engines perform better for specific workloads.
  • Choosing the excellent storage engine for your use case can extensively have an impact on the overall performance of your applications.
  • Here, there are four types of storage engines used by MongoDB :
    • MMAPv1
    • WiredTiger
    • Encrypted
    • In-memory

    • Types of Storage Engines

    MMAPv1 :

    • This type of storage engine uses memory-mapped files to store its data.
    • A segment of virtual memory that has been assigned a direct byte-for-byte correlation with some portion of a file.
    • This storage engine allows a great deal of performance for heavy read applications.
    • Indexes and Data are mapped into virtual space.
    • Data access is placed into RAM.
    • It will swap out memory to disk to make space for the newly requested data if the OS runs out of RAM and an application requests for memory.
    • MongoDB’s memory was managed by operating system’s virtual memory subsystem.

    WiredTiger :

    • From Mongo 3.0 WiredTiger is the default storage engine.
    • This type storage engine uses document-level concurrency control for write operations. At the same time multiple clients can modify different documents of a collection.
    • It uses only intent locks at the global, database and collection levels when the storage engine detects conflicts between two operations, one will incur a write conflict causing MongoDB to transparently retry that operation.
    • MongoDB utilizes both the filesystem cache and WiredTiger internal cache. the wired tiger cache will use 50% of RAM minus 1 GB or 256 MB by default.
    • It is efficient use of CPU cores and RAM.
    • It allows more tuning storage engines than MMVPv1. 7 to 10X better write performance. 80% less storage with compression.
    • In WiredTiger internal cache collection level data is uncompressed and uses a different representation from the on-disk format.

    Encrypted :

    • It is available in MongoDB enterprise only.
    • During encryption master keys and database keys are used.
    • Master key encrypts the database keys, data is encrypted with the database keys.
    • Application-Level Encryption provides encryption on a per-field or per-document basis within the application layer.

    In-memory :

    • Available in the enterprise editions starting from version 3.2.6.
    • It Handles ultra-high throughput with high availability and low latency.
    • Low latency on less in-memory infrastructure and more predictable.
    • Supports high level infrastructure based on zonal sharding.
    • Indexing support and MongodB rich query capability.
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