Oracle expert advanced programming learning notes (2)

The Oracle architecture 3 main components: 1. File: 5 files that make up the disc instance (parameter file, control file, data file, temporary data file, redo log file) 2. System global zone SGA (System Global Area) : Java pool, shared pool, etc. 3. Physical process and thread: run three different types of processes on the database (server server process, background backgroud process, slave SLAVE process)

Terminology: Database: Genealogy of physical operating system files: a set of Oracle processes and SGA relationships: A database can be loaded with multiple instances and open Open instances to load and open a separate database, and open And loaded databases do not have to be the same at startup

Document: 1. Parameter file: tnsnames.ora, listener.ora, sqlnet.ora, protocol.ora, names.ora, sman.ora, ldap.ora (Refer to "Oracle Net Administrator Guide" $ Oracle_Home / DBS / INT . ORA: Content is a series of variable names and values ​​for Such as: db_name = "wmdb" db_block_size = 8192Control_files = ("c: /oradata/control01.ctl", "c: /oradata/control02.ctl") ... there are some parameters not explained in the Oracle documentation. The following is started in addition to setting up in the development environment _trace_files_public = True This parameter, other non-explanation parameters is best not to change

2. Data file: Database Database -> Table Space TableSpace -> Segment Segment -> Extent Extensions -> Block Block 1) Database consisting of one or more tablespaces 2) Table space consisting of one or more data File composition, one tablespace has one or more segments 3) a segment (table, index, etc.) consist of multiple extensions, and the segment is in the tablespace, but in the tablespace, there are multiple data files in multiple data files. .4) An extended area is some consecutively allocated blocks on the disk, an extension area in a table space, and a single file 5 in the table space is the smallest allocation unit and I / O unit in the database. Its size is fixed when the database is created.

3. Temporary file When memory is not enough to save an intermediate result of a large-scale sorting operation (set), Oracle uses temporary files to store them, permanently data, such as table or index, is not stored in temporary files, but temporary tables or The content of the temporary index may be stored in a temporary file.

Recommend the local management temporary table space to configure the database? ??

4. Control file a fairly small file, at most 64m, directory data file INIT . Ot, containing Oracle needs, tells the location of the database and the online redo log file to tell the database and online redo log file. The instance control file also provides additional information to Oracle, such as checkpoints, database names, timestamps created by the database, archive reform log history, etc.

5. Transaction logs for redo log file data, only use 1) Online Redo Logs only when recovering

Memory structure 1. SGA (System Global Area) 2.pga (User Global Area)