Postgres DB는 이렇게 생겼다!

 target: compare Mysql and Postgres.

1. why?

when I prepare the presentation ON timescaleDB’s func. I got interesting on Postgres.

because the TSDB is based on Postgres. So I had investigate the structure of Postgres.

 

2. feature of Postgres

• support a variety data that doesn’t support in Mysql
  • audio, video, image ….
• Comparing the RDBMS(mysql), these are similar on performance.
  • because two DBs have updated continuously.
  • So These days, It is difficult to say which one is better.

 

3. Structure of Postgres

• Heap : storage file.
• Block(page) : bundle of data.
• Tuple : row data save type.

 

 Full-scan

1. when full scan like(with out index, pk …., any other standards),

SELECT * FROM table where name = 'good721'

put every data on memory.

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index-scan

 

with index.

• query touch the index, “what is the block and index that WHERE is located”
• deev dive, the index work with B-tree.