In-depth parsing of the Oracle boot process internal initialization

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1 Oracle Boot options;

When the Oracle database is started on startup, Oracle looks for the initialization parameter file in the default location, $oracle_home/dbs, where Oracle looks for the appropriate initialization file in the following order:

Spfile$oracle_sid.ora

Spfile.ora

Init$oracle_sid.ora

The Oracle database can be started in several ways, starting in different ways that will affect the start of the database, the boot state is Nomount (the database is not mounted)-->mount (database is loaded)-->open (database open)

1.1 STARTUP Nomount;

Sql> Startup Nomountoracle instance started. Total System Global area 1603411968 bytesfixed size 2253664 bytesvariable size 1375734944 bytesdatabase buffers 218103 808 Bytesredo buffers 7319552 bytes

Oracle read the parameters file, open the instance, start the Oracle background process, and assign the SGA to Oracle. The database state is not mounted at this time.

1.2 ALTER DATABASE MOUNT;

sql> ALTER DATABASE Mount;database altered.

Oracle opens and reads the control file, obtaining the name and location of the data file and redo log file. The database finishes loading at this time.

1.3 ALTER DATABASE OPEN;

sql> ALTER DATABASE Open;database altered.

Oracle opens data files and redo log files so Oracle can provide services externally.

2 Viewing the internal boot process with 10046 events

sql> startup Nomount; Total System Global area 1603411968 bytesfixed size 2253664 bytesvariable size 1375734944 bytesdatabase buffers 218103 808 Bytesredo buffers 7319552 bytessql> oradebug setmypidstatement processed. Sql> Oradebug tracefile_name/oracle/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_3682.trcsql> Alter Session Set Events ' 10046 Trace name context forever,level 12 '; Session altered. sql> ALTER DATABASE Mount;database altered. sql> ALTER DATABASE Open;database altered.

View Udump File

[oracle[email protected] ~]$ more /oracle/app/oracle /DIAG/RDBMS/ORCL/ORCL/TRACE/ORCL_ORA_3682.TRC 

Trace file/oracle/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_3682.trcoracle Database 11g Enterprise Edition Release 11.2.0.4.0-64bit Productionwith The partitioning, OLAP, Data Mining and Real application testing Optionsoracle_h OME =/oracle/app/oracle/product/11.2.0system Name:linuxnode name:rhel6release:2.6.32-431.el6.x86_64vers Ion: #1 SMP Sun Nov 22:19:54 EST 2013machine:x86_64vm name:vmware version:6instance NAME:ORCL

Oracle database mount starts the Read control file, writes the log file

... wait  #140528657591192:  nam= ' Control file sequential read '  ela= 8 file# =0 block#=1 blocks=1 obj#=-1 tim=1502627703012561wait  #140528657591192:  nam= ' Control file sequential read '  ela= 2 file#=1 block#=1 blocks=1  obj#=-1 tim=1502627703012583wait  #140528657591192:  nam= ' control file sequential  Read '  ela= 47 file#=0 block#=3 blocks=8 obj#=-1 tim=1502627703012650wait   #140528657591192:  nam= ' Control file sequential read '  ela= 13 file#=1  block#=3 blocks=8 obj#=-1 tim=1502627703012674...WAIT  #140528657591192:  nam= ' Adr block file read '  ela= 847  =0  =0  =0 obj#=-1  tim=1502627707123048WAIT  #140528657591192:  nam= ' Adr block file read '  ela=  576  =0  =0  =0 obj#=-1 tim=1502627707124068wait  #140528657591192:  nam= ' Adr block file read '  ela= 562  =0  =0  =0 obj#=-1  tim=1502627707125013WAIT  #140528657591192:  nam= ' Adr block file read '  ela=  473  =0  =0  =0 obj#=-1 tim=1502627707125891 ...

The Oracle database open procedure reads the control file information and compares it to the head of the read disk data file

alter database openend of stmtparse  #140528657591192: c=0,e=274,p=0,cr=0,cu=0,mis=1,r= 0,dep=0,og=1,plh=0,tim=1502627713479605wait  #140528657591192:  nam= ' control file sequential  read '  ela= 8 file#=0 block#=1 blocks=1 obj#=-1 tim= 1502627713479904wait  #140528657591192:  nam= ' Control file sequential read '  ela=  4 file#=1 block#=1 blocks=1 obj#=-1 tim=1502627713479922wait # 140528657591192: nam= ' Control file sequential read '  ela= 2 file#=0  block#=15 blocks=1 obj#=-1 tim=1502627713479931...wait  #140528657591192:  nam= ' Disk  FILE OPERATIONS I/O '  ela= 11 fileoperation=2 fileno=1 filetype=2  obj#=-1 tim=1502627713481300WAIT  #140528657591192:  nam= ' disk file operations  I/O '  ela= 6 fileoperation=2 fileno=2 filetype=2 obj#=-1 tim=1502627713481317wait  #140528657591192:  nam= ' Disk  FILE OPERATIONS I/O '  ela= 4 fileoperation=2 fileno=3 filetype=2 obj#=- 1 tim=1502627713481327wait  #140528657591192:  nam= ' disk file operations i/o '  ela= 4 fileoperation=2 fileno=4 filetype=2 obj#=-1 tim= 1502627713481338wait  #140528657591192:  nam= ' disk file operations i/o '  ela=  5 fileoperation=2 fileno=201 filetype=2 obj#=-1 tim=1502627713481351

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In-depth parsing of the Oracle boot process internal initialization