dukeofhazardz commented on issue #354: URL: https://github.com/apache/age/issues/354#issuecomment-1507596405
Summary of the third chapter of the book 'Internals of PostgreSQL' The third chapter of 'The Internals of PostgreSQL' covers the query processing in PostgreSQL. The chapter overviews the five subsystems of the backend which handles all queries issued by the connected client, and they are; The parser which generates a parse tree from an SQL statement in plain text. The analyzer which carries out a semantic analysis of a parse tree and generates a query tree. The rewriter which transforms a query tree using the rules stored in the rule system if such rules exist. The planner which generates the plan tree which can be executed effectively from the query tree. and lastly, the executor which executes the query via accessing the tables and indexes in the order that was created by the plan tree. Furthermore the chapter also touches on the cost estimation in single query, which includes the start up, run and total costs. And also the sequential and index scans and the respective formulas used to estimate their start up, run, and total costs. Finally, the join operations in postgresql with their different cost estimations and the Plan Tree of Single and Multiple-Table Queries, which has to do with the planner getting the cheapest access path and estimating the costs of all possible access paths and choices, and then choosing cheapest one -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
