/1 Why is PostgreSQL voted the ๐ฆ๐จ๐ฌ๐ญ ๐ฅ๐จ๐ฏ๐๐ ๐๐๐ญ๐๐๐๐ฌ๐ by Stackoverflow 2022 Developer Survey?
The diagram shows the many use cases by PostgreSQL - one database that includes almost ๐๐ฅ๐ฅ ๐ญ๐ก๐ ๐ฎ๐ฌ๐ ๐๐๐ฌ๐๐ฌ developers need.
/2 ๐นOLTP (Online Transaction Processing)
We can use PostgreSQL for CRUD (Create-Read-Update-Delete) operations.
/3 ๐นOLAP (Online Analytical Processing)
We can use PostgreSQL for analytical processing. PostgreSQL is based on ๐๐๐๐ (Hybrid transactional/analytical processing) architecture, so it can handle both OLTP and OLAP well.
/4 ๐นFDW (Foreign Data Wrapper)
A FDW is an extension available in PostgreSQL that allows us to access a table or schema in one database from another.
/5 ๐นStreaming
PipelineDB is a PostgreSQL extension for high-performance time-series aggregation, designed to power real-time reporting and analytics applications.
/6 ๐นGeospatial
PostGIS is a spatial database extender for PostgreSQL object-relational database. It adds support for geographic objects, allowing location queries to be run in SQL.
/7 ๐นTime Series
Timescale extends PostgreSQL for time series and analytics. For example, developers can combine relentless streams of financial and tick data with other business data to build new apps and uncover unique insights.
/8 ๐นDistributed Tables
CitusData scales Postgres by distributing data & queries.
/9 ๐ Over to you: Which database do you like the most?
/1 What are the differences between B-Tree and LSM-Tree?
/2 ๐-๐๐ซ๐๐
B-Tree is the most widely used indexing data structure in almost all relational databases.
The basic unit of information storage in B-Tree is usually called a โpageโ. To look up a key, it traces down the range of keys until the actual value is found.
/3 ๐๐๐-๐๐ซ๐๐
LSM-Tree (Log-Structured Merge Tree) is widely used by many NoSQL databases, such as Cassandra, LevelDB, and RocksDB.
LSM-trees maintain key-value pairs and are persisted to disk using a Sorted Strings Table (SSTable), in which the keys are sorted.
Letโs first define what โsecureโ means. A โsecureโ chat in a messaging App generally means the message is encrypted at the sender side and is only decryptable at the receiver side. It is also called โE2EEโ (end-to-end encryption).
/1 What protocol does ๐จ๐ง๐ฅ๐ข๐ง๐ ๐ ๐๐ฆ๐ข๐ง๐ use to transmit data? TCP or UDP?
A common practice is to use RUDP (Reliable UDP). It adds a ๐ซ๐๐ฅ๐ข๐๐๐ฅ๐ mechanism on top of UDP so that it provides ๐ฆ๐ฎ๐๐ก ๐ฅ๐จ๐ฐ๐๐ซ ๐ฅ๐๐ญ๐๐ง๐๐ฒ than TCP and guarantees accuracy.
/2 The diagram below shows how reliable data delivery is implemented in online gaming to get eventually-synchronized states.
/3 Suppose there is a big fight in a simulation shooter game. Characters A, B, and C open fires in sequence. How does the game server transmit the states from the game server to the game client?
/1 How do fintech startups find new opportunities among so many payment companies? What do PayPal, Stripe, and Square do exactly? ๐
/2 ๐ธSteps 0-1: The cardholder opens an account in the issuing bank and gets the debit/credit card. The merchant registers with ISO or MSP (Member Service Provider) for in-store sales. ISO/MSP partners with payment processors to open merchant accounts.
/3 ๐ธSteps 2-5: The acquiring process.
The payment gateway accepts the transaction and collects payment info. It is then sent to a payment processor, which uses customer information to collect payments. The acquiring processor sends the transaction to the card network.
/1 ๐๐ก๐๐ญ ๐ข๐ฌ ๐๐๐ 3.0? Why doesnโt it have ๐๐๐ฌ?
The diagram below shows Web 1.0/Web 2.0/Web 3.0 from a bird's-eye view.
/2 ๐นWeb 1.0 - Read Only
Between 1991 and 2004, the internet is like a ๐๐๐ญ๐๐ฅ๐จ๐ of ๐ฌ๐ญ๐๐ญ๐ข๐ ๐ฉ๐๐ ๐๐ฌ. We can browse the content by jumping from one hyperlink to another. It doesnโt provide any interactions with the content.
/3 ๐นWeb 2.0 - Read Write
From 2004 to now, the internet has evolved to have search engines, social media apps, and recommendation algorithms backed apps.