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rozpocznij naukę
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rozpocznij naukę
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alternative to MongoDb. An open-source document-oriented NoSQL database, implemented in Erlang
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four examples of Wide-column store rozpocznij naukę
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Apache Cassandra, Apache HBase, BigTable, scylla
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Database replication master/slave rozpocznij naukę
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Master -original, only writes, slaves - copies, only reads
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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LRU - Least recently used, LFU - Least Frequently used, FIFO - First in First out
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CDN - describe what it is rozpocznij naukę
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A CDN is a network of geographically dispersed servers used to deliver static content. CDN servers cache static content like images, videos, CSS, JavaScript files, etc.
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rozpocznij naukę
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is a system or repository of data stored in its natural/raw format,[1] usually object blobs or files
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rozpocznij naukę
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session is kept in NoSQL database. It is no longer kept in web server. Each server in the cluster can access state data from the database
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Load balancer, sticky session rozpocznij naukę
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user who authenticated in one of the servers in a cluster, will be redirected to the same server for future calls (for certain amount of time that is longer than the session timeout)
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Disadvantages of sticky session rozpocznij naukę
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more difficult to add or remove servers, more difficult to handle server failures
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Advantages of stateless web tier vs stateful web tier rozpocznij naukę
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simpler, more robust and scalable
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Shared data store for state data (sessions), what to use rozpocznij naukę
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rozpocznij naukę
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geolocation DNS routing - to make sure, that the client is directed to the closest datacenter
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Logging and monitoring tool rozpocznij naukę
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Datadog, Matomo, prometeus, Pendo
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example of Key business metrics rozpocznij naukę
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each shard has the same schema, but data are specific to shard- user data is allocated to specific shard - hash function is used to find the shard e.g. user_id % 4
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Sharding key vs partition key rozpocznij naukę
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Sharding key vs partition key
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Two Problems with sharding rozpocznij naukę
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Resharding data - r.g. One shard goes down, Celebrity problem = hotspot key problem
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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1PB ~ 1 000 000 000 000 000
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rozpocznij naukę
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A memory bank built into the CPU chip. Also known as the "primary cache," an L1 cache is the fastest memory in the computer and closest to the processor.
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rozpocznij naukę
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is a messaging pattern used to model an information exchange that implies the delivery (or spreading) of a message to one or multiple destinations possibly in parallel
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rozpocznij naukę
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simple notification service
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rozpocznij naukę
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Amazon Elastic Compute Cloud
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allows users to rent virtual computers on which to run their own computer applications
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rozpocznij naukę
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Amazon Elastic Block Store
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block level storage volumes for use with EC2 instances. You can create a file system on top of these volumes, or use them in any way you would use a block device (such as a hard drive)
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rozpocznij naukę
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is a fully managed proprietary NoSQL database service that supports key–value and document data structures
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is a relational database service developed and offered by Amazon Web Services beginning in October 2014 Aurora is available as part of the Amazon Relational Database Service (RDS).
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rozpocznij naukę
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rozpocznij naukę
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Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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rozpocznij naukę
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10 microseconds = 10000 ns
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Send 1KB via 1Gbps network rozpocznij naukę
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read 1MB sequentially from memory rozpocznij naukę
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read 1MB sequentially from disk rozpocznij naukę
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read 1MB sequentially from network rozpocznij naukę
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rozpocznij naukę
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The difference is that sharding implies the data is spread across multiple computers while partitioning does not. Partitioning is about grouping subsets of data within a single database instance
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consistent hashingConsistent hashing is a special kind of hashing such that when a hash table is re-sized and consistent hashing is used, only k/n keys need to be remapped on average, where k is the number of keys, and n is the number of slots
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consistent hashing describe algorithm rozpocznij naukę
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To determine which server a key is stored on, we go clockwise from the key position on the ring until a server is found.
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