Pak Bowo, apakah parallel query hanya bisa dipakai dalam kondisi full
table scan? explain query yang terkena index kq hasilnya seperti ini
SQL> select /*+ parallel(TRANS,2) */ COUNT(*) from TRANS;
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=3 Card=1)
1 0 SORT (AGGREGATE)
2 1 PARTITION RANGE (ALL)
3 2 INDEX (FAST FULL SCAN) OF 'TRANS_J2_I' (NON-UNIQUE)
(Cost=3 Card=551937334)
jika full table scan
select /*+ parallel(TRANS,2) */ kode, COUNT(*) from TRANS GROUP BY
kode;
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=237481
Card=551937334 Bytes=2207749336)
1 0 SORT* (GROUP BY) (Cost=237481 Card=551937334 Bytes=2207749
:Q22001336)
2 1 SORT* (GROUP BY) (Cost=237481 Card=551937334 Bytes=22077
:Q2200049336)
3 2 PARTITION RANGE* (ALL)
:Q22000
4 3 TABLE ACCESS* (FULL) OF 'TRANS' (Cost=102802 Car :
Q22000d=551937334 Bytes=2207749336)
1 PARALLEL_TO_SERIAL SELECT /*+ CIV_GB */ A1.C0,
COUNT(SYS_OP_CSR(
A1.C1,0)) FROM :Q22000 A1 GROUP BY
A
2 PARALLEL_TO_PARALLEL SELECT /*+ PIV_GB */ A1.C0 C0,
SYS_OP_MSR(COU
NT(*)) C1 FROM (SELECT /*+
NO_EXPAND
3 PARALLEL_COMBINED_WITH_PARENT
4 PARALLEL_COMBINED_WITH_PARENT
maaf jika saya keliru membaca plan .. masih awam pak ..
--- In [email protected], "Yulius Wibowo" <[EMAIL PROTECTED]
.> wrote:
> Pastikan nilai parameter parallel_max_servers nya lebih dari 0.
>
> Contoh:
>
> SQL> conn / as sysdba
> SQL> alter system set parallel_max_servers=4;
> SQL> show parameter parallel
>
> NAME TYPE VALUE
> ------------------------------------ ----------- ------
> parallel_max_servers integer 4
>
> SQL> conn scott/tiger
>
> SQL> set autotrace traceonly explain
> SQL> select /*+ PARALLEL(emp,4) */ * from emp;
>
> Execution Plan
> ----------------------------------------------------------
> 0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=1 Card=16
Bytes=13
> 92)
>
> 1 0 PX COORDINATOR
> 2 1 PX SEND* (QC (RANDOM)) OF ':TQ10000' (Cost=1 Card=16
> Byt :Q1000
> es=1392)
>
> 3 2 PX BLOCK* (ITERATOR) (Cost=1 Card=16
> Bytes=1392) :Q1000
> 4 3 TABLE ACCESS* (FULL) OF 'EMP' (TABLE) (Cost=1
> Card=1 :Q1000
> 6 Bytes=1392)
> 2 PARALLEL_TO_SERIAL
> 3 PARALLEL_COMBINED_WITH_CHILD
> 4 PARALLEL_COMBINED_WITH_PARENT
>
>
> Bowo
>
>
>
> --- In [email protected], "cyuniart" <[EMAIL PROTECTED]>
wrote:
> > Selamat malam,
> > Agar query bisa dijalankan secara parallel apa saja ya yang harus
di
> > setting, saya coba jalankan skrip
> >
> > select /*+ parallel(t,2) */ * from t;
> >
> > tapi dilihat dari explain plan kq sepertinya tidak dijalankan
secara
> > parallel. Apakah parameter parallel_automatic_tuning
mempengaruhinya .
> > .(saya set true)..
> >
> > thx,
> > Condro
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