How PostgreSQL Stores a Row
Every database gives you a row and every database lies a little about what that row is. MySQL gives you a record copied into a row buffer. SQLite gives you a record in a b-tree …
Storage
How PostgreSQL Locks Buffers Without LWLocks
Every time PostgreSQL reads a page it does two things: it pins the shared buffer that holds the page, and it takes a content lock on that buffer so that nobody rewrites the bytes …
How PostgreSQL Computes Page Checksums Fast
Every page PostgreSQL writes to disk gets a checksum: two bytes in the page header that let the server notice, on the next read, that the page it just read is not the page it …
How PostgreSQL Hashes Lookups
Every hash table in PostgreSQL is one of two things, and the difference between them explains a surprising amount of PostgreSQL’s behaviour. One is dynahash: a chained hash table …
How PostgreSQL Defers and Speeds Up Tuple Deformation
A heap tuple is a packed byte string with no field boundaries in it. Column 3 might be at byte 27, column 4 at byte 31, column 5 — if it is a text — at byte 35. Getting to column …