optimiser problem
От | Gavin Sherry |
---|---|
Тема | optimiser problem |
Дата | |
Msg-id | Pine.LNX.4.21.0105151449140.10801-100000@linuxworld.com.au обсуждение исходный текст |
Ответы |
Re: optimiser problem
Re: optimiser problem |
Список | pgsql-hackers |
Hi all, Can't for the life of me figure out the problem here: CREATE TABLE "b" ( "id" bigint, "string" text ); CREATE INDEX "b_pkey" on "b" using btree ( "id" "int8_ops" ); Given 2000 tuples in b, vacuum verbose analyze: test=# vacuum verbose analyze b; NOTICE: --Relation b-- NOTICE: Pages 13: Changed 0, reaped 0, Empty 0, New 0; Tup 2002: Vac 0, Keep/VTL 0/0, Crash 0, UnUsed 0, MinLen 48, MaxLen 48; Re-using: Free/Avail. Space 0/0; EndEmpty/Avail. Pages 0/0. CPU 0.00s/0.01u sec. NOTICE: Index b_pkey: Pages 12; Tuples 2002. CPU 0.00s/0.03u sec. NOTICE: --Relation pg_toast_2140890-- NOTICE: Pages 0: Changed 0, reaped 0, Empty 0, New 0; Tup 0: Vac 0, Keep/VTL 0/0, Crash 0, UnUsed 0, MinLen 0, MaxLen 0; Re-using: Free/Avail. Space 0/0; EndEmpty/Avail. Pages 0/0. CPU 0.00s/0.00u sec. NOTICE: Index pg_toast_2140890_idx: Pages 1; Tuples 0. CPU 0.00s/0.00u sec. NOTICE: Analyzing... VACUUM So, a select on b as follows: SELECT * FROM b WHERE id=1; should not have an EXPLAIN like this: test=# explain verbose select * from b where id=1; NOTICE: QUERY DUMP: { SEQSCAN :startup_cost 0.00 :total_cost 38.02 :rows 2 :width 20 :qptargetlist ({ TARGETENTRY :resdom { RESDOM :resno 1 :restype 20 :restypmod -1 :resname id :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1 :varattno 1 :vartype 20 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 1}} { TARGETENTRY :resdom { RESDOM :resno 2 :restype 25 :restypmod -1 :resname string :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1 :varattno 2 :vartype 25 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 2}}) :qpqual ({ EXPR :typeOid 16 :opType op :oper { OPER :opno 416 :opid 474 :opresulttype 16 } :args ({ VAR :varno 1 :varattno 1 :vartype 20 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 1} { CONST :consttype 23 :constlen 4 :constbyval true :constisnull false :constvalue 4 [ 1 0 0 0 ] })}) :lefttree <> :righttree <> :extprm () :locprm () :initplan <> :nprm 0 :scanrelid 1 } NOTICE: QUERY PLAN: Seq Scan on b (cost=0.00..38.02 rows=2 width=20) version is 7.1. Thanks Gavin
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