Thanks Imre, this is a very important comment, 128 bits is much smaller than 45*8+2=362.
Very glad to know that, thank you very much!
James
------------------ Original ------------------
Date: Thu, Nov 21, 2019 08:39 PM
To: "James(王旭)"<wangxu@xxxxxxxxx>;
Cc: "pgsql-general"<pgsql-general@xxxxxxxxxxxxxx>;
Subject: Re: How should I specify work_mem/max_worker_processes if I want to do big queries now and then?
> uuid character varying(45) NOT NULL,
Just a comment.
IF this is a real UUID ( RFC 4122, ISO/IEC 9834-8:2005 ) ;
THEN you can use the built in "UUID Type" https://www.postgresql.org/docs/11/datatype-uuid.html
"UUID would be the fastest because its 128 bits -> 16 bytes and comparisons are done numerically."
The smaller size can be important for your index size ! : "quotes_pkey PRIMARY KEY (symbol_id, uuid);"
Imre
