Mega Code Archive

A verbose explanation of a simpler query, with the VERBOSE keyword

postgres=# postgres=# CREATE TABLE employee ( postgres(# ID int, postgres(# name varchar(10), postgres(# salary real, postgres(# start_date date, postgres(# city varchar(10), postgres(# region char(1) postgres(# ); CREATE TABLE postgres=# postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (1, 'Jason', 40420, '02/01/94', 'New York', 'W'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (2, 'Robert',14420, '01/02/95', 'Vancouver','N'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (3, 'Celia', 24020, '12/03/96', 'Toronto', 'W'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (4, 'Linda', 40620, '11/04/97', 'New York', 'N'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (5, 'David', 80026, '10/05/98', 'Vancouver','W'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (6, 'James', 70060, '09/06/99', 'Toronto', 'N'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (7, 'Alison',90620, '08/07/00', 'New York', 'W'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (8, 'Chris', 26020, '07/08/01', 'Vancouver','N'); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (9, 'Mary', 60020, '06/09/02', 'Toronto', 'W'); INSERT 0 1 postgres=# postgres=# select * from employee; id | name | salary | start_date | city | region ----+--------+--------+------------+-----------+-------- 1 | Jason | 40420 | 1994-02-01 | New York | W 2 | Robert | 14420 | 1995-01-02 | Vancouver | N 3 | Celia | 24020 | 1996-12-03 | Toronto | W 4 | Linda | 40620 | 1997-11-04 | New York | N 5 | David | 80026 | 1998-10-05 | Vancouver | W 6 | James | 70060 | 1999-09-06 | Toronto | N 7 | Alison | 90620 | 2000-08-07 | New York | W 8 | Chris | 26020 | 2001-07-08 | Vancouver | N 9 | Mary | 60020 | 2002-06-09 | Toronto | W (9 rows) postgres=# postgres=# postgres=# postgres=# -- A verbose explanation of a simpler query, with the VERBOSE keyword: postgres=# postgres=# EXPLAIN VERBOSE SELECT * FROM employee; QUERY PLAN ------------------------------------------------------------- {SEQSCAN :startup_cost 0.00 :total_cost 20.30 :plan_rows 1030 :plan_width 45 :targetlist ( {TARGETENTRY :expr {VAR :varno 1 :varattno 1 :vartype 23 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 1 } :resno 1 :resname id :ressortgroupref 0 :resorigtbl 19576 :resorigcol 1 :resjunk false } {TARGETENTRY :expr {VAR :varno 1 :varattno 2 :vartype 1043 :vartypmod 14 :varlevelsup 0 :varnoold 1 :varoattno 2 } :resno 2 :resname name :ressortgroupref 0 :resorigtbl 19576 :resorigcol 2 :resjunk false } {TARGETENTRY :expr {VAR :varno 1 :varattno 3 :vartype 700 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 3 } :resno 3 :resname salary :ressortgroupref 0 :resorigtbl 19576 :resorigcol 3 :resjunk false } {TARGETENTRY :expr {VAR :varno 1 :varattno 4 :vartype 1082 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 4 } :resno 4 :resname start_date :ressortgroupref 0 :resorigtbl 19576 :resorigcol 4 :resjunk false } {TARGETENTRY :expr {VAR :varno 1 :varattno 5 :vartype 1043 :vartypmod 14 :varlevelsup 0 :varnoold 1 :varoattno 5 } :resno 5 :resname city :ressortgroupref 0 :resorigtbl 19576 :resorigcol 5 :resjunk false } {TARGETENTRY :expr {VAR :varno 1 :varattno 6 :vartype 1042 :vartypmod 5 :varlevelsup 0 :varnoold 1 :varoattno 6 } :resno 6 :resname region :ressortgroupref 0 :resorigtbl 19576 :resorigcol 6 :resjunk false } ) :qual <> :lefttree <> :righttree <> :initPlan <> :extParam (b) :allParam (b) :nParamExec 0 :scanrelid 1 } Seq Scan on employee (cost=0.00..20.30 rows=1030 width=45) (126 rows) postgres=#