DB
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Transactional locking mechanism and Multi-version concurrency control(MVCC)DB/RDB 2019. 9. 30. 10:26
1. Overview 1.1 Data Concurrency and Consistency Data concurrency: Ensures that users can access data at the same time Data consistency: Ensures that each user sees a consistent view of the data, including visible changes made by the user's own transactions and committed transactions of other users 2. Multiversion Read Consistency (MVCC) 2.1 Oracle Multi-versioning is the ability to simultaneous..
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MongoDB vs CasandraDB/Nosql 2019. 9. 30. 09:31
1. Overview When it comes to NoSQL databases, MongoDB and Cassandra may seem similar but are quite different. Both have similar use cases but are not intended for transactional data (i.e., accounting systems) 2. Description 2.1 Comparison of Features Feature MongoDB Cassandra Development language C++ Java Storage Type BSON files(Document-based) Column(Wide-columns) Expressive object model Yes No..
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Memcached vs. RedisDB/InMemory 2019. 9. 29. 13:54
1. Overview Both tools are powerful, fast, in-memory data stores that are useful as a cache. Both can help speed up your application by caching database results, HTML fragments, or anything else that might be expensive to generate. But Redis is more powerful, more popular, and better supported than Memcached. Memcached can only do a small fraction of the things Redis can do. Redis is better even..
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Buffer vs. cacheDB/InMemory 2019. 9. 29. 13:53
1. Overview The semantics of a "buffer" and a "cache" are not totally different. even so, there are fundamental differences in intent between the process of caching and the process of buffering. A cache is typically used to store frequently accessed data. The data in a cache changes over time but the cache itself may be permanent. Caches often have sophisticated designs that support random acces..
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Cache, Write-through, and Write-backDB/InMemory 2019. 9. 29. 12:36
1. Overview A caching method in which modifications to data in the cache aren't copied to the cache source until absolutely necessary. Write-back caching is available on many microprocessors, including all Intel processors since the 80486. With these microprocessors, data modifications (e.g., write operations) to data stored in the L1 cache aren't copied to main memory such as RAM. until absolut..
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MongoDBDB/Nosql 2019. 9. 20. 10:11
1. Overview MongoDB is a cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schema. MongoDB is developed by MongoDB Inc. and licensed under the Server Side Public License (SSPL) 2. Description 2.1 Ad hoc queries MongoDB supports field, range query, and regular expression searches. Queries can return specific fields of ..
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OLTP, OLAP, and ETLDB/RDB 2019. 9. 11. 14:28
1. Overview 1.1 On-line Transaction Processing (OLTP) OLTP stands for On-line Transaction Processing. OLTP based systems (account, ticket booking, banking systems, money transfer system) are used to perform a large number of short transactions. Almost all of the database queries in OLTP system consist of commands insert, update, delete. Select queries are mainly designed to enable users to selec..
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Difference between Nosql and SQLDB/Nosql 2019. 8. 25. 11:50
1. Overview When it comes to choosing a database the biggest decisions are picking a relational (SQL) or non-relational (NoSql) data structure. While both the databases are viable options still there are certain key differences between the two that users must keep in mind when making a decision 2. NoSQL 2.1 What is NoSQL NoSQL databases are purpose-built for specific data models and have flexibl..