Re: How should I specify work_mem/max_worker_processes if I want to do big queries now and then?

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 ------------------
From: &nbsp;"Imre Samu"<pella(dot)samu(at)gmail(dot)com&gt;;
Date: &nbsp;Thu, Nov 21, 2019 08:39 PM
To: &nbsp;"James(王旭)"<wangxu(at)gu360(dot)com&gt;;
Cc: &nbsp;"pgsql-general"<pgsql-general(at)postgresql(dot)org&gt;;
Subject: &nbsp;Re: How should I specify work_mem/max_worker_processes if I want to do big queries now and then?

&nbsp;

&gt;&nbsp; uuid character varying(45) NOT NULL,

Just a comment.
IF this is a real UUID (&nbsp;RFC 4122, ISO/IEC 9834-8:2005 )&nbsp;;&nbsp;
THEN you can use the built in&nbsp; "UUID Type"&nbsp;&nbsp;https://www.postgresql.org/docs/11/datatype-uuid.html

"UUID would be the fastest because its 128 bits -&gt; 16 bytes and comparisons are done numerically."
https://stackoverflow.com/questions/32189129/performance-difference-between-uuid-char-and-varchar-in-postgresql-table

The smaller size can be important for your index size ! :&nbsp; &nbsp;"quotes_pkey PRIMARY KEY (symbol_id, uuid);"

Imre