Question

如果你能解决这个问题，请提前致谢。

我在Oracle 11g r2数据库上运行，我正在构建一个新的物化视图，虽然创建视图只需要大约6分钟来创建，但每天刷新它需要大约42分钟。下面刷新此代码的过程REFRESH_ACTIVE_NON_ACQU_MV，创建物化视图的代码位于底部。有什么我做错的吗？

当我使用下面的代码进行简单的刷新时，需要25分钟。

begin
    EXECUTE IMMEDIATE  'ALTER SESSION ENABLE PARALLEL DML';
    dbms_mview.REFRESH('ACTIVE_NON_ACQU_MV');
end;
/

但是下面的程序需要42分钟。我不明白为什么刷新比物化视图的创建需要更长的时间？以及为什么两次刷新在刷新时间方面相差很大。

PROCEDURE REFRESH_ACTIVE_NON_ACQU_MV
IS
   l_method VARCHAR2(1) := 'C';
BEGIN
   EXECUTE IMMEDIATE  'ALTER SESSION ENABLE PARALLEL DML';
   Dbms_Mview.Refresh(LIST=>'ACTIVE_NON_ACQU_MV', 
   METHOD=>l_method, atomic_refresh=>FALSE, PARALLELISM=>8); 

END REFRESH_ACTIVE_NON_ACQU_MV;

创建下面的物化视图的代码。

PROMPT Drop MATERIALIZED VIEW ACTIVE_NON_ACQU_MV
-- create create MATERIALIZED VIEW ACTIVE_NON_ACQU_MV
DROP MATERIALIZED VIEW ACTIVE_NON_ACQU_MV;
-- create create MATERIALIZED VIEW ACTIVE_NON_ACQU_MV
PROMPT Create MATERIALIZED VIEW ACTIVE_NON_ACQU_MV
CREATE MATERIALIZED VIEW ACTIVE_NON_ACQU_MV (SUPPLIER,
                                             BROADCASTER,
                                             PRODUCTION_TITLE,
                                             PRODUCTION_NUMBER,
                                             SERIES_TITLE,
                                             SUPPLIED_SOURCE_IND,
                                             THIRD_PARTY_GROUP_ID,
                                             BRO_BROADCAST_BY_TP_SURR_ID,
                                             STATION_ID                                         
                                             )                                           
TABLESPACE PRBLK_MV_BD_A
PCTUSED    0
PCTFREE    10
INITRANS   2
MAXTRANS   255
STORAGE    (
            INITIAL          64K
            NEXT             1M
            MAXSIZE          UNLIMITED
            MINEXTENTS       1
            MAXEXTENTS       UNLIMITED
            PCTINCREASE      0
            BUFFER_POOL      DEFAULT
           )
NOCACHE
LOGGING
NOCOMPRESS
PARALLEL ( DEGREE DEFAULT INSTANCES DEFAULT )
BUILD IMMEDIATE
USING INDEX
            TABLESPACE PRBLK_MV_BI_A
            PCTFREE    10
            INITRANS   2
            MAXTRANS   255
            STORAGE    (
                        INITIAL          64K
                        NEXT             1M
                        MINEXTENTS       1
                        MAXEXTENTS       UNLIMITED
                        PCTINCREASE      0
                        BUFFER_POOL      DEFAULT
                       )
REFRESH ON DEMAND
WITH ROWID
AS 
/* Formatted on Mon/06/02/2017 10:07:52 (QP5 v5.267.14150.38573) */
select x.supplier_name as supplier , 
       x.broadcaster_name as broadcaster , 
       ptle.title as production_title , 
       x.production_number as production_number , 
       stle.title as series_title , 
       x.production_source as supplied_source_ind , 
       x.third_party_group_id , 
       x.bro_broadcast_by_tp_surr_id,
       x.STATION_ID
FROM
(select usages.production_number,
       usages.prod_exploitation_cre_surr_id,
       usages.bro_broadcast_by_tp_surr_id,
       usages.THIRD_PARTY_SURR_ID,
       usages.SUPPLIER_NAME,
       usages.THIRD_PARTY_GROUP_ID,
       usages.STATION_ID,
       usages.BROADCASTER_NAME,
       prod.cre_surr_id,
       prod.production_source,
       prod.prod_series_cre_surr_id
from productions prod,
(SELECT --+ parallel(uh)
       uh.production_number, 
       uh.prod_exploitation_cre_surr_id,
       uh.bro_broadcast_by_tp_surr_id,
       supplier_details.THIRD_PARTY_SURR_ID,
       supplier_details.SUPPLIER_NAME,
       supplier_details.THIRD_PARTY_GROUP_ID,
       supplier_details.STATION_ID,
       supplier_details.BROADCASTER_NAME,
       row_number() over(partition by uh.production_number order by uh.production_number) prod_rows
FROM usage_headers uh,
        (SELECT third_party.surr_id AS THIRD_PARTY_SURR_ID, 
                third_party.supplier_name as SUPPLIER_NAME,
                third_party.supplier_group_id AS THIRD_PARTY_GROUP_ID, 
                third_party.dn_root_tp_surr_id AS THIRD_PARTY_ROOT_ID, 
                bro.station_id AS STATION_ID, 
                bro.dn_tp_name AS BROADCASTER_NAME
         FROM   broadcasters bro,
                    (SELECT tp.surr_id, 
                            tp.name AS supplier_name, 
                            tp.tp_surr_id AS supplier_group_id, 
                            tp.dn_root_tp_surr_id 
                    FROM third_parties tp 
                    CONNECT BY PRIOR tp.surr_id = tp.tp_surr_id 
                    START WITH tp.surr_id IN (SELECT surr_id FROM ETL_ACQUIRED_MASTER WHERE NVL(exclude_flag,'N') <> 'Y')) third_party 
        WHERE third_party.surr_id = bro.tp_surr_id) supplier_details
WHERE uh.bro_broadcast_by_tp_surr_id = supplier_details.THIRD_PARTY_SURR_ID
AND uh.production_number IS NOT NULL
AND uh.prod_exploitation_cre_surr_id IS NOT NULL
AND uh.right_type IN ('M', 'B')
AND NVL (uh.dn_uls_usage_status, '3') NOT IN ('9', '11')
AND uh.udg_surr_id IS NOT NULL
 AND NOT EXISTS (SELECT 1 
                 FROM prblk.production_usage_components puc 
                 WHERE puc.uh_surr_id = uh.surr_id 
                 AND PUC.DISTRIBUTION_STATUS IS NOT NULL)) usages
WHERE usages.prod_rows = 1
AND usages.prod_exploitation_cre_surr_id = prod.cre_surr_id 
AND prod.production_source <> 'AP') x
LEFT OUTER JOIN titles ptle ON ( ptle.cre_surr_id = x.cre_surr_id AND ptle.tt_code = 'R') 
LEFT OUTER JOIN titles stle ON ( stle.cre_surr_id = x.prod_series_cre_surr_id AND stle.tt_code = 'R');

COMMENT ON MATERIALIZED VIEW ACTIVE_NON_ACQU_MV IS 'snapshot of none acquired productions - ACTIVE_NON_ACQU_MV';

PROMPT select on 'ACTIVE_NON_ACQU_MV' to APPS_ACCESS_ROLE_BLK
GRANT SELECT ON ACTIVE_NON_ACQU_MV TO APPS_ACCESS_ROLE_BLK;

Answer 1

尝试做：

exec dbms_mview.refresh('ACTIVE_NON_ACQU_MV', 'C', atomic_refresh=>false);

false的原子刷新意味着它将截断然后插入。如果使用原子刷新，它将执行事务性删除+插入（我相信默认）。＆＃34;更安全＆＃34;但可以更长时间完成。

当然，不能保证总是花费相同的时间来完成刷新。例如，如果您有许多其他进程同时运行（竞争资源），您可能会遇到＆＃34;缓慢＆＃34;与其他运行时相比。

此外，如果其他人在长时间运行的事务中访问该快照表，则可能会阻止您尝试执行完整刷新（使用atomic_refresh =＆gt; false）。因此，如果需要一段时间，可能会检查阻塞锁。

创建Oracle物化视图需要6分钟，但刷新需要42分钟，为什么？

1 个答案: