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(I) Compare the following two methods:To_char (start_time, 'yyyy-mm-dd hh24: MI: ss') = '2017-06-06 16:18:30'AndStart_time = to_date ('2017-06-06 16:18:30 ', 'yyyy-mm-dd hh24: MI: ss ')The latter is recommended at any time !! (Ii) Simple

(Optional) indicates a small part of a row set.This row set can be a base table, view, a join result set, or a group by operation.The selectivity is limited by the query predicate, such as last_name = 'Smith 'or a joint predicate. For example,

the DELETE command is used to remove the tables data either selective or all and put the data in an rollback segment as well where from a read consistent view or a flashback view can be seen even after commit and one can rollback the tables data

(I) Unreasonable full table scan for large tables For details, click the open link. The V $ session_longops view records all SQL statements that exceed 6 seconds.Most of them are full table scan statements! (Ii) Poor statement sharing OLTP is often

The incremental checkpoint is used to balance the load. It is triggered by the fast_start_mttr_target parameter and is incrementally written out. Therefore, checkpoint_change # is delayed and will not be updated immediately.Three methods are used to

The undo tablespace has a temper, that is, new transactions are given priority and long queries are lagging behind! There are two scenarios: Query before and after After query: If [query SCN> submit SCN] If [query SID = submit Sid] Returns a new

What is full table scan? Data access methods that unreasonably consume a large amount of resources Why is there a full table scan?The reasons are as follows:① Missing Indexes② The index is restrained③ Improper use of table Connection Technology④

Year-on-year comparison Definition: development level during the reporting period compared with the same period last year   Purpose: eliminate the influence of seasonal changes   Formula: year-on-year development speed = current development

(I) What is data block consistency? Each data block header has a "checksum" field. Before the data block is written back to the disk, Oracle recalculates the checksum. Record this field and write it back to the disk. The next time a data block is

Before the server process obtains the redo allocation latch for redo log Buffer Allocation, You need to sniff the redo log file to check whether there is sufficient space. If the space is insufficient, the SP will send a request for the switch log

Monitoring reports today: some machines in an LDAP data center cannot log on In the past, I looked at it and summarized the thinking path: (I) locate the problem and determine the scope of the problem LDAP cannot be logged in. Local Accounts can

Insufficient undo space may cause a ORA-30036 or ORA-01555. We create a small undo tablespace and execute a large transaction, then we can simulate the ORA-30036. Sys @ orcl> Create undo tablespace thinktbs datafile

As a programmer, although he is dealing with English every day However, it is a headache to see an English document or an English Technical article. Especially when Google is used for search, many solutions are in English. There are also some

create or replaceprocedure print_table( p_query in varchar2, p_date_fmt in varchar2 default 'dd-mon-yyyy hh24:mi:ss' ) --

IP addresses can be divided: ● Public Address: one address can only be used in one place ● Private address: it can be reused in different scenarios. Private IP Range: 255.10.0.0.0 255.10.255.255.255 255.172.16.0.0 255.172.31.255.255 255.192.168.0.0 2

AMDNew Computing Architecture Huma(Heterogeneous uniform memory access) Data no longer needs to be moved between the CPU and GPU. The GPU can directly access the CPU memory, greatly improving the efficiency. When the CPU reads and writes data,

(I) ARP Definition ARP (Address Resolution Protocol), Address Resolution Protocol, resolve the IP address to a MAC address For example, 192.168.1.1-> 00-1e-37-44-86-5e. If a computer uses a data frame for communication within the LAN, the data

① Install the software package [root@localhost ~]# rpm -qa | grep vnc-server vnc-server-4.1.2-14.el5_6.6 ② Set the User PasswordAfter the user password is set, a hidden. VNC directory is generated under the root directory.

Environment: sys@ORCL> select * from v$version where rownum=1;BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prodsys@ORCL> !uname -aLinux localhost.localdomain 2.6.18-

1 rman must at least work in the Mount state, that is, there is a control file. Start method: RMAN target/ 2. Run the OS command from RMAN:Host; then you can jump out of RMANExit; return to RMANRun the SQL command from RMAN:SQL "SQL commands" 3