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ORA-29857问题SQL> drop tablespace demotsdata including contents and datafiles;drop tablespace demotsdata including contents and datafiles*ERROR at line 1:ORA-29857: domain indexes and/or secondary ob
dsc集群,dm_svc.conf配置如下:$ cat /etc/dm_svc.confTIME_ZONE=(480)LANGUAGE=(cn)DMDB=(172.16.10.20:5236,172.16.10.22:5236)DIRECT=(Y)[DMDB]LOGIN_MODE=(1)SWITCH_TIME=(3)SWITCH_INTERVAL=(10)测试连接时报:[dmdba@dmdsc2
直方图中有low_value、high_value值,如果显示为10进制可以使用下面方法:字符串select utl_raw.cast_to_number(low_value) from dual;declare n varchar2(2000); begin dbms_stats.convert_raw_value('100001',n); dbms_output.put_line(n); en
通用写法:select * from (select /*+ FIRST_ROWS(n) */ a.*, ROWNUM rnum from (select object_id, object_name, LAST_DDL_TIME from tt order by 1) a wh
_optimizer_unnest_scalar_sq参数是12.1引入的隐含参数,目的是支持标量子查询展开,通常能展开的子查询被改写为hash外连接的形式,能够看到HASH GROUP BY关键字,可能导致临时表空间激增或升级前sql异常缓慢。默认该参数启用:set linesize 132column name format a30column value format a25sel
impdp导入错误:错误1impdp *****/*** directory=DATA_PUMP_DIR dumpfile=scott_%U.dmp logfile=scott.log parallel=2ORA-31693: Table data object "NC65"."PUB_WORKINGTASKLOG" failed to load/unload and is being skip
索引插入通常发生在索引的右边,当在单调递增的列上定义索引时,大量且高并发的DML(先删除后插入)会导致索引不能及时的放入指定的位置,oracle内部会根据索引的实际存储情况,对索引进行叶块的分裂操作,以满足索引的维护需求,这个过程会导致该等待事件的产生。可考虑的解决办法:1.创建hash或REVERSE索引可根据 AWR 报告的 'Segments by Row Lo
MOVE丢弃不满足条件的数据12c+版本支持,https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/ALTER-TABLE.html#GUID-552E7373-BF93-477D-9DA3-B2C9386F2877FILM_IDTITLEUK_RELEASE_DATELENGTH_IN_MINUTE
Lag和Lead分析函数可以在同一次查询中取出同一字段的前N行的数据(Lag)和后N行的数据(Lead)作为独立的列。LAG语法https://docs.oracle.com/en/database/oracle/oracle-database/18/sqlrf/LAG.html#GUID-68081CD0-72BE-4C0A-AA6B-AD39FFA7BCF2LEAD语法htt
测试脚本create table movies ( year_of_release number(4), name varchar2(60), gross_sales number(12) );insert into movies (year_of_release,name,gross_sales) values (1977,'star wars ep. iv: a new ho
create table toys ( toy_id integer not null primary key, toy_name varchar2(20) not null);declare start_time pls_integer; num_rows pls_integer := 100000;begin start_time := dbms_utility.ge
脚本1create table deliveries ( delivery_id integer not null constraint delivery_pk primary key, tracking_code varchar2(20) not null constraint deli_tracking_u unique, delivery_date date
---字符转二进制utl_raw.cast_to_raw---二进制转数字utl_raw.cast_to_number---二进制转字符utl_raw.cast_to_varchar2通常在统计信息中我们需要看直方图对应的low_value,high_value可以使用此函数转换SQL> select d.low_value,d.high_value,utl_raw.cast_to_varc
pivoting功能行转列语法SELECT ....FROM <table-expr> PIVOT ( aggregate-function(<column>) FOR <pivot-column> IN (<value1>, <value2>,..., <valuen>)
达梦数据库内置了2个示例帐户:DMHR和BOOKSHOP,在安装过程是可选的。如果安装过程未选择,数据库安装完成后可进行手动安装,步骤如下:1.脚本文件安装脚本位于DM_HOME/samples/instance_script下,有gbk和utf8两个版本:[root@dmdb01 instance_script]# pwd/dm8/samples/instance_script[roo
当两个或更多人尝试以不同的顺序锁定相同的行时,就会发生死锁,发生死锁时数据库会主动解锁,死锁的检测时间受隐含参数“_LM_DD_INTERVAL”控制,在Oracle 11g中,默认为10s,在Oracle 10g中,默认为60s。单机与集群发生死锁时在日志中展现是不一致的:单机:ORA-00060: Deadlock detected集群:Global Enqueue Services De
适用于dm8可查询以下项目: Database Basic Information Database Summary Database Overview Instance State Database Version Database License Database Components Database Options Database Prop
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yum grouplist显示不完整,缺少很多包:# yum grouplistLoaded plugins: ulninfoAvailable Environment Groups: Minimal Install Infrastructure Server File and Print Server Basic Web Server Virtualization Host
面对大表查实际行数比较费时,可使用oracle提供的抽样方法。---select /*+no_parallel(t) no_parallel_index(t) dbms_stats cursor_sharing_exact use_weak_name_resl dynamic_sampling(0) no_monitoring no_substrb_pad*/ count(*) from TES
DISPLAY参数DBMS_XPLAN.DISPLAY( table_name IN VARCHAR2 DEFAULT 'PLAN_TABLE', statement_id IN VARCHAR2 DEFAULT NULL, format IN VARCHAR2 DEFAULT 'TYPICAL', filter_preds IN VAR
二进制安装后无此文件,加一个# vim /usr/lib/systemd/system/mysqld.service[Unit]Description=MySQL ServerDocumentation=man:mysqld(7)Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.htmlAfter=network.targ
有权限的人手贱把gi目录的权限进行修改...WTF!方法1:----Oracle 11.2版本:# cd $GRID_HOME/crs/install/# ./rootcrs.pl -init----Oracle 12c及以上版本:# cd $GRID_HOME/crs/install/# ./rootcrs.sh -init方法2:找一台版本一致的gi环境,进入到相应的目录获取正确的权限:# c
该值没有统一的标准,通常在每分钟的增量在10-15算正常。netstat -s | fgrep reassembles353357449 packet reassembles failed353359152 packet reassembles failed353360314 packet reassembles failed353361547 packet reassembles failed3
alter session set timed_statistics = true;alter session set statistics_level=all;alter session set max_dump_file_size = unlimited;alter session set events '10046 trace name context forever,level 12';&
CBO基于成本的优化器改变了SQL执行过程中的对谓词选择性的评估方式,使得执行计划更加合理,这种评估是以列的选择性为基础,在数据均匀分布的情况下没有问题,如果数据存在倾斜,通过绑定变量传入的值会导致走错误的执行计划,在9i中,引入"Bind Peeking"以试图解决与绑定变量的选择性相关的问题,初始的绑定值与后续传入的绑定值具有不同的选择性时计划可能只使用第一次硬解析生成的计划。10g时默认的统
谓词缺少统计信息,优化器使用OPTIMIZER_DYNAMIC_SAMPLING测试谓词选择性生成指定的执行计划。支持的采样级别如下:Level 0: Disables dynamic sampling.Level 1: Sample all tables that have not been analyzed that meet certain criteria.Level 2: Apply d
Histogram bucket limitationsHistograms are limited to 254 buckets so if there are more than 254 distinct values and there is no single value that dominates the column's dataset then histograms may not
https://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:1035431863958create or replace procedure print_table( p_query in varchar2 )AUTHID CURRENT_USERisl_theCursor integer default dbms_
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