I build a little test table with columns id serial, a text, b text. Why the cost of max(id) is made as a seq scan, as
isfor count(id)? This is a problem with very large tables.
IMHO, select max(id) could be done using the index prova_id_key.
Your opinion? TIA. Stefano
mydb=> explain select max(id) from prova;
NOTICE: QUERY PLAN:
Aggregate (cost=43.00 rows=1000 width=4)
-> Seq Scan on prova (cost=43.00 rows=1000 width=4)
EXPLAIN
mydb=> explain select count(id) from prova;
NOTICE: QUERY PLAN:
Aggregate (cost=43.00 rows=1000 width=4)
-> Seq Scan on prova (cost=43.00 rows=1000 width=4)
--
Dott. Stefano Bargioni
Biblioteca della Pontificia Universita' della Santa Croce - Roma
<mailto:bargioni@usc.urbe.it> <http://www.usc.urbe.it>
Personal web page: <http://www.usc.urbe.it/html/php.script?bargioni>
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