alter database backup controlfile to trace

https://blog.csdn.net/ghostliming/article/details/49302745
https://blog.csdn.net/guardiangel/article/details/9317879

Database carried out

alter database backup controlfile to trace;

Suddenly thought, what is the meaning of this statement, what does it do?
So first, I am looking for

background_dump_dest

The document, found inside the only alert file is just modified, and only one piece of information

Wed Oct 21 12:25:50 CST 2015
alter database backup controlfile to trace
Wed Oct 21 12:25:50 CST 2015
Completed: alter database backup controlfile to trace

And then I understand, performed by the user, the following should be udump Yeah, so go to the next udump, found

/u01/app/oracle/admin/orcl10/udump/orcl10_ora_7043.trc
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORACLE_HOME = /u01/app/oracle/product/10.2.0/dbhome_1
System name:    Linux
Node name:      lmsingle10
Release:        2.6.18-308.el5
Version:        #1 SMP Fri Jan 27 17:17:51 EST 2012
Machine:        x86_64
Instance name: orcl10
Redo thread mounted by this instance: 1
Oracle process number: 22
Unix process pid: 7043, image: oracle@lmsingle10 (TNS V1-V3)
 
*** ACTION NAME:() 2015-10-21 12:25:50.573
*** MODULE NAME:(sqlplus@lmsingle10 (TNS V1-V3)) 2015-10-21 12:25:50.573
*** SERVICE NAME:(SYS$USERS) 2015-10-21 12:25:50.573
*** SESSION ID:(140.269) 2015-10-21 12:25:50.573
*** 2015-10-21 12:25:50.573
-- The following are current System-scope REDO Log Archival related
-- parameters and can be included in the database initialization file.
--
-- LOG_ARCHIVE_DEST=''
-- LOG_ARCHIVE_DUPLEX_DEST=''
--
-- LOG_ARCHIVE_FORMAT=%t_%s_%r.dbf
--
-- DB_UNIQUE_NAME="orcl10"
--
-- LOG_ARCHIVE_CONFIG='SEND, RECEIVE, NODG_CONFIG'
-- LOG_ARCHIVE_MAX_PROCESSES=2
-- STANDBY_FILE_MANAGEMENT=MANUAL
-- STANDBY_ARCHIVE_DEST=?/dbs/arch
-- FAL_CLIENT=''
-- FAL_SERVER=''
--
-- LOG_ARCHIVE_DEST_10='LOCATION=USE_DB_RECOVERY_FILE_DEST'
-- LOG_ARCHIVE_DEST_10='OPTIONAL REOPEN=300 NODELAY'
-- LOG_ARCHIVE_DEST_10='ARCH NOAFFIRM NOEXPEDITE NOVERIFY SYNC'
-- LOG_ARCHIVE_DEST_10='REGISTER NOALTERNATE NODEPENDENCY'
-- LOG_ARCHIVE_DEST_10='NOMAX_FAILURE NOQUOTA_SIZE NOQUOTA_USED NODB_UNIQUE_NAME'
-- LOG_ARCHIVE_DEST_10='VALID_FOR=(PRIMARY_ROLE,ONLINE_LOGFILES)'

-- LOG_ARCHIVE_DEST_STATE_10=ENABLE
--
-- Below are two sets of SQL statements, each of which creates a new
-- control file and uses it to open the database. The first set opens
-- the database with the NORESETLOGS option and should be used only if
-- the current versions of all online logs are available. The second
-- set opens the database with the RESETLOGS option and should be used
-- if online logs are unavailable.
-- The appropriate set of statements can be copied from the trace into
-- a script file, edited as necessary, and executed when there is a
-- need to re-create the control file.
--
--     Set #1. NORESETLOGS case
--
-- The following commands will create a new control file and use it
-- to open the database.
-- Data used by Recovery Manager will be lost.
-- Additional logs may be required for media recovery of offline
-- Use this only if the current versions of all online logs are
-- available.
-- After mounting the created controlfile, the following SQL
-- statement will place the database in the appropriate
-- protection mode:
--  ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE
STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "ORCL10" NORESETLOGS  ARCHIVELOG
    MAXLOGFILES 16
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 8
    MAXLOGHISTORY 292
LOGFILE
  GROUP 1 '/u01/app/oracle/oradata/orcl10/redo01.log'  SIZE 50M,
  GROUP 2 '/u01/app/oracle/oradata/orcl10/redo02.log'  SIZE 50M,
  GROUP 3 '/u01/app/oracle/oradata/orcl10/redo03.log'  SIZE 50M
-- STANDBY LOGFILE
DATAFILE
  '/u01/app/oracle/oradata/orcl10/system01.dbf',
  '/u01/app/oracle/oradata/orcl10/undotbs01.dbf',
  '/u01/app/oracle/oradata/orcl10/sysaux01.dbf',
  '/u01/app/oracle/oradata/orcl10/users01.dbf'
CHARACTER SET ZHS16GBK

So this statement is to create controlfile statement of the current file into the file under trc udump in.