Oracle database Architecture and Learning path

1. What is the relational database?

A relational model is a model of a database created by a relational model and a two-dimensional table to store data.

Oracle,mysql,sqlserver

2. What is a NoSQL database?

Key-value Saving a database

HBase, Redis

3. Basic concepts of Oracle Database

(1) An Oracle database and multiple Oracle instances

What is a database? A physical concept, a file stored on a hard disk

What is an instance? Image of the database file in memory

Cluster (rac:real application cluster)? Multiple instances for a database

Architecture for 4.oracle

(1) Storage structure

(*) Physical storage structure: files on disk

<1> data files: *.dbf saved data

(*) must exist

System: Key Information

Sysaux: System-assisted data files, such as: AWR information

UNDOTBS: Restore data (Restore Tablespace) data for critical rollback operations (historical data)

Temp: Temporary data such as: Sort, temp table

(*) Optional user data file users01.dbf,example01.dbf

<2> log file: *.log transaction-related operations log

<3> control File: *. CTL equivalent to configuration file

(1) record the location of the DBF and log files of the data file

(2) The meta-information of Rman backup is recorded

<4> parameter files: initialization parameters during startup Pfile < text files 9i> and spfile< binaries 10g,11g.12g>

show  parameter spfile; -- pfile and SPFile convert each other Create pfile='/home/oracle/pfile.ora'from   spfile;

<5> Archive log: Log file archive, change to a local store

<6> Backup Files Rman: (*) backup set, default (*) mirrored copy

<7> Password file:

<8> Alarm log file: Alert_orcl.log TRC trace log file TRM trace information metadata

-- Storage location dump;

(*) Logical storage structure

Tablespace: A table space can have multiple data files

Segment segment: A table is a segment, a table segment, and an index segment

Zone extent: the smallest unit of allocated space

Block: Minimum storage unit 8k

-- the size of the Block show parameter db_block_size;

(2) Process structure

1DBWn Database Write process

2.LGWR Write Log

3 Client Processes

4.CKPT: Checkpoint Process

5.PMON: Process Monitor

6.smon:system Monitor (fastest way to turn off Oracle: Kill-9 smon_pid)

(3) Memory structure

(*) Sga

(*) Pga

SGA and PGA Size settings:

-- sga=0 SGA is determined by the database itself show parameter SGA; -- pga=0 size is determined by the database itself Show parameter PGA; -- Automatic memory Management

Oracle database Architecture and Learning path