Notes

LevelDB is not A SQL Database

LevelDB stores keys, values and other arbitrary byte arrays. Data is sorted by key. It supports batching write forward and reverse iteration, and compression of data using Google's Snappy compression library.



LevelDB is not a SQL database. Similar to other NoSQL and dbm stores it does not have a relational data model and does not support SQL queries. Additionally, it lacks support for indexes. Applications utilize LevelDB as a library, since it doesn't provide an interface for command-line or server.



MariaDB 10.0 comes with an engine for storage that allows users to search LevelDB tables directly from MariaDB. [6]



LevelDB is based on ideas from Google's Bigtable data base system. The table implementation for the Bigtable database system was developed in 2004. It is built on an entirely different Google code base that is different from the LevelDB code. This code base is dependent on a number Google code libraries that aren't open source. Therefore, it was difficult to open source the code. Sanjay Ghemawat and Jeff Dean wanted to create an application similar to the Bigtable tablet stack. It would have a minimum of dependencies, be open sourced and compatible with Chrome's IndexedDB implementation. They wrote LevelDB starting in early 2011, with the same general design as the Bigtable tablet stack, but without sharing any of the code. [7]



Usage[edit]



LevelDB is used as the backend database of Google Chrome's IndexedDB and is one of the backends that are supported for Riak. [88 Bitcoin Core and go–ethereum also store blockchain metadata using the LevelDB Database. 9 Minecraft Bedrock Edition uses a modified version to store chunks and entity data storage. Autodesk AutoCAD 2016 also uses LevelDB.



Performance[edit]



Google has provided benchmarks that compare LevelDB's performance with SQLite or Kyoto Cabinet in different scenarios. 11 LevelDB outperforms both SQLite and Kyoto Cabinet in write operations and sequential-order read operations. Skins LevelDB also excels at batch writing, but is slower than SQLite when dealing with large amounts of data. After SQLite configuration issues were discovered in an earlier version, the benchmarks for the current version were updated. The updated benchmarks[13] show LevelDB outperforms Berkeley DB. However, these tests also show OpenLDAP LightningDB to be a lot faster (10x in certain scenarios) for read operations (e.g. The rest of the test is nearly identical, with the exception of batch and synchronous write (see the link above).



Please take note that the benchmarks mentioned above are from the year 2011 through 2014. They are not historical in any way. SQLite, for example, became significantly more efficient. [14]



Bugs and reliability[edit]



LevelDB has history of corruption issues in databases. [15][16][17][18][19][20] A study from 2014 has found that, on older (non-checksummed) file systems, the database could become corrupted after a crash or power failure. [21]



Lightning Memory-Mapped Database rocksDB is a free and open-source software portal


References[edit]



^ "Release 1.23". 23 February 2021 Retrieved 13 March 2021. "Google Research Scientists and Engineers": Jeffrey Dean. Google, Inc. ^ "Research Scientists and Engineers: Sanjay Ghemawat". Google, Inc. Google Open-Sources NoSQL Database Called LevelDB ReadWriteWeb. July 30, 2011. The original article was removed on August 16, 2011. Retrieved July 30, 2011. ^ "Google Open Source Blog: LevelDB: A Fast Persistent Key-Value Store". Google, Inc. ^ LevelDB storage engine ^ Jeff Dean. "LevelDB mailing list Current Status of LevelDB" ^ LevelDB. Docs.basho.com. Retrieved 2013-09-18. ^ Andreas M. Antonopoulos. "Chapter 7. The Blockchain". Retrieved on January 8, 2015. ^ "Bedrock Edition level format". ^ "LevelDB Benchmarks". Google, Inc. Retrieved from the original on 2011-08-20. ^ "LevelDB Benchmark discussion". Database Microbenchmarks, Archived 2014-08-10 at the Wayback Machine Symas Corp. 2012-09. Retrieved 22 October 2016."Measuring the CPU utilization in SQLite". ^ Repairing LevelDB ^ Issues * google/leveldb * GitHub Unrecoverable corruption in Chromium ^ Corruption in syncthing ^ Corruption following power loss Corruption in Ethereum All File Systems Are Not created equal: The complexity of creating crash-resistant applications. 2014. pp. 433-448. ISBN 9781931971164. External links[edit[edit



Official website


v


t


E


Chromium OpenRefine Tesseract


Carbon Dart Go Sawzall


AMP Angular AngularJS Beam Bazel Blockly Closure Tools Cpplint FlatBuffers Flutter Gears Gerrit Guava gRPC Gson Guetzli Guice gVisor Kubernetes LevelDB libvpx NaCl OR-Tools Polymer TensorFlow


AOSP Chromium OS Fuchsia gLinux Goobuntu


Code-in Google LLC v. Oracle America, Inc.


Homepage: https://mc-skins.org/