{"id":2103,"date":"2011-01-31T09:03:00","date_gmt":"2011-01-31T08:03:00","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/"},"modified":"2011-01-31T09:03:00","modified_gmt":"2011-01-31T08:03:00","slug":"oracle-basics-2-data-storage","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/","title":{"rendered":"Oracle Basics (2) &#8211; Data Storage"},"content":{"rendered":"<p>What is finally the primary objective of a database? Storing Data \ud83d\ude00<br \/>\nThe question is, how Oracle makes it. For many beginners, a confusing topic is to get the picture between physical storage and logical one. So how does it work?<\/p>\n<p>The storage in an Oracle database can be seen from 2 points of view:<\/p>\n<ul>\n<li>Database users<\/li>\n<li>System Administrators<\/li>\n<\/ul>\n<p>On one hand you have users who see tables, indexes and so on. This could be summarized has objects or, so called in Oracle, Segments. On the other hand you have system adminitrators (Unix or Windows, doesn&#8217;t matter&#8230;), who see files and blocks.<br \/>\nAs DBA you are the missing link between these 2 points of view \ud83d\ude44<br \/>\nSo, how do we go down from an Object, Segment, to the files and OS blocks? Take a look down there.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" style=\"display: block; margin-left: auto; margin-right: auto;\" src=\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/logical_physical_Storage.gif\" alt=\"logical_physical_Storage\" width=\"420\" height=\"287\" \/><\/p>\n<p>As we already said, data are stored in Segments (Tables, Indexes&#8230;). Segments are stored in Tablespaces and these are the bridge between logical storage and physical storage.<\/p>\n<p>On one side, tablespaces are physical collection of data files, which are made of operating system blocks. On the other side, tablespaces are logical collection of Segments (Tables, indexes&#8230;). You could almost compare them to folders where you organize your data in.<\/p>\n<p>Segments are composed of Extents, which are pieces of data. As Segments will most probably grow over time, Extents are added to follow the Segments&#8217; size increase. Extents are made of Oracle Blocks.<\/p>\n<p>Finally we reach the lowest level, where Oracle Blocks are groups of Operating System Blocks. The Oracle block size is defined on database level but can also be customized per tablespace. The Oracle block size must be greater or equal and a multiple of the OS blocks. This is basis while speaking about Oracle performances. Many best practices can be found on Internet about it.<\/p>\n<p><strong>Let&#8217;s take a small example<\/strong>:<\/p>\n<p>1 Database with 8KB Oracle Blocks on File Systems of 4KB blocks.<br \/>\n==&gt; 1 Oracle Block = 2 OS Blocks<br \/>\nNow we can have a look a little bit deeper in all these elements<\/p>\n<h3>Tablespaces and Data Files<\/h3>\n<p>As seen, Tablespaces are logical containers composed of one or more datafiles.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" style=\"display: block; margin-left: auto; margin-right: auto;\" src=\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/tablespaces.gif\" alt=\"tablespaces\" width=\"355\" height=\"179\" \/><\/p>\n<p>Oracle provides 2 types of tablespaces:<\/p>\n<ul>\n<li>Smallfile tablespaces &#8211; most commonly used<\/li>\n<li>Bigfile tablespaces<\/li>\n<\/ul>\n<p>The Smallfile tablespaces are composed of several datafiles, while Bigfiles are composed of a single data file. One of the reasons why Oracle introduced big file tablespaces was the limitation on the number of data file composing a database (usually 64k). In Bigfile tablespaces, the data files max size limit is much higher than for small file tablespaces.<\/p>\n<p>How does it work? You may have already heard about ROWID, which is a unique ID for each row in a database. In fact the ROWID is more than just an ID, it is also the pointer to the row location. Between Smallfiles and Bigfiles tablespaces, the ROWID is slightly different.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" style=\"display: block; margin-left: auto; margin-right: auto;\" src=\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/rowid.gif\" alt=\"rowid\" width=\"310\" height=\"146\" \/><\/p>\n<p>As by definition Bigfile tablespaces are made of a single file, there is no File Nb needed within the ROWID. Therefore the Block Nb is coded on 4GB instead of 4kB.<\/p>\n<p>If we take our example of a 8kB database again, we have the following:<br \/>\nSmallfile max size: 4kB blocks X 8kB (size of each block) = 32 GB per file<br \/>\nBigfile max size: 4GB blocks X 8kB (size of each block) = 32 TB per file<\/p>\n<p>The tablespace management can be done either in the Oracle Data Dictionary or, since 10g, be Locally Managed. Nowadays almost all tablespaces are configured as Locally Managed TableSpace (LMTS). This means that the space management is done in a bitmap stored in the Segment Header of the tablespace. The LMTS has the advantage to reduce &#8211; but not avoid &#8211; fragmentation and improve DDL performances.<\/p>\n<p>While creating data files, 2 solutions are possible. You can either create them with fix size which will be allocated at file creation, or you can create them in autoextend mode. Autoextend data files are created with an initial size and will then grow up automatically until the defined max size. If no max size is given at data file creation, then the limit defined by the Oracle Block Size (see above about ROWID and max data file size) will be applied.<\/p>\n<p>Here are the 2 main views in oracle to get information on tablespaces and data files: dba_tablespaces, dba_data_files<\/p>\n<pre class=\"brush: sql; gutter: true; first-line: 1\"><samp><code><\/code><\/samp>SQL&gt; desc dba_tablespaces;\nName\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 Null? \u00a0 \u00a0 \u00a0 \u00a0 Type\n-------------------------- ------------- ------------------------------------\nTABLESPACE_NAME\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 NOT NULL\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\nBLOCK_SIZE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 NOT NULL\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nINITIAL_EXTENT \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nNEXT_EXTENT\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nMIN_EXTENTS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 NOT NULL\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nMAX_EXTENTS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nMAX_SIZE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0 NUMBER\nPCT_INCREASE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nMIN_EXTLEN\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nSTATUS \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(9)\nCONTENTS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(9)\nLOGGING\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(9)\nFORCE_LOGGING\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(3)\nEXTENT_MANAGEMENT\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(10)\nALLOCATION_TYPE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(9)\nPLUGGED_IN\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 VARCHAR2(3)\nSEGMENT_SPACE_MANAGEMENT\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0\u00a0\u00a0 VARCHAR2(6)\nDEF_TAB_COMPRESSION\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0\u00a0 \u00a0 VARCHAR2(8)\nRETENTION\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(11)\nBIGFILE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(3)\nPREDICATE_EVALUATION\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(7)\nENCRYPTED\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(3)\nCOMPRESS_FOR\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(12)\nSQL&gt; desc dba_data_files;\n Name\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 Null?\u00a0\u00a0\u00a0 Type\n -------------------------- -------- -------------------------------\n FILE_NAME\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0\u00a0 \u00a0\u00a0 VARCHAR2(513)\n FILE_ID\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\n TABLESPACE_NAME\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\n BYTES\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\n BLOCKS \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 NUMBER\n STATUS \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0 \u00a0 \u00a0 \u00a0\u00a0 VARCHAR2(9)\n RELATIVE_FNO\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 NUMBER\n AUTOEXTENSIBLE \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(3)\n MAXBYTES\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\n MAXBLOCKS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 NUMBER\n INCREMENT_BY\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 NUMBER\n USER_BYTES\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\n USER_BLOCKS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\n ONLINE_STATUS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 VARCHAR2(7)<\/pre>\n<h3>Segments and Extents<\/h3>\n<p>Segment is the generic name used in Oracle databases to represent objects like tables, indexes or partitions. These are stored in Data Files in pieces called Extents.<\/p>\n<p>The Segments can be either in MANUAL mode or in AUTO mode &#8211; Automatic Segment Space Management (ASSM)<br \/>\nIn earlier Oracle version, the MANUAL mode managed free blocks and free space in a Free List stored the Data Dictionary, which overloaded System tablespace. Since Oracle 10g and ASSM the free blocks and the free space are managed in a bitmap in the Segment Header of each Tablespace.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" style=\"display: block; margin-left: auto; margin-right: auto;\" src=\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/segments.gif\" alt=\"segments\" width=\"454\" height=\"190\" \/><\/p>\n<p>The 2 main views to find segments and extents information are: dba_segments and dba_extents<\/p>\n<pre class=\"brush: sql; gutter: true; first-line: 1\"><samp><\/samp>SQL&gt; desc dba_segments\nName\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 Null?\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0 Type\n-------------------------- --------------- -----------------------------------\nOWNER\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\nSEGMENT_NAME\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(81)\nPARTITION_NAME \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\nSEGMENT_TYPE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(18)\nSEGMENT_SUBTYPE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(10)\nTABLESPACE_NAME\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\nHEADER_FILE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nHEADER_BLOCK\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nBYTES\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0 NUMBER\nBLOCKS \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nEXTENTS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nINITIAL_EXTENT \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0 \u00a0\u00a0\u00a0 NUMBER\nNEXT_EXTENT\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nMIN_EXTENTS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nMAX_EXTENTS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0 NUMBER\nMAX_SIZE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nRETENTION\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(7)\nMINRETENTION\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nPCT_INCREASE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nFREELISTS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nFREELIST_GROUPS\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0 \u00a0\u00a0\u00a0 NUMBER\nRELATIVE_FNO\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 NUMBER\nBUFFER_POOL\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(7)\nFLASH_CACHE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(7)\nCELL_FLASH_CACHE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(7)\nSQL&gt; desc dba_extents\nName\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 Null?\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Type\n-------------------------- --------------- ------------------------------------\nOWNER\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\nSEGMENT_NAME\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(81)\nPARTITION_NAME \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\nSEGMENT_TYPE\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 VARCHAR2(18)\nTABLESPACE_NAME\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VARCHAR2(30)\nEXTENT_ID\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nFILE_ID\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nBLOCK_ID\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nBYTES\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 NUMBER\nBLOCKS \u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NUMBER\nRELATIVE_FNO\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0\u00a0 NUMBER<\/pre>\n<p>Another important concept to understand, in case of Table segments, is the &#8220;High Watermark&#8221; (HWM). It defines the position of the last formated block for the segment. It means that in case of a Full table scan (FTS &#8211; i.e. select * from table1;) Oracle will go through all the segment&#8217;s blocks up to the HWM position.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" style=\"display: block; margin-left: auto; margin-right: auto;\" src=\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/hwm.gif\" alt=\"hwm\" width=\"528\" height=\"209\" \/><\/p>\n<p>The key here is to keep in mind that deleting data, which means free blocks, does NOT move the HWM position. This can have a quite huge impact on requests performances.<br \/>\nThe only ways to move down the HWM is either to truncate the table, but this also means losing all data, or to make a table reorganization. However this quite beyond our current topic \ud83d\ude00<\/p>\n<p>So here we are with this introduction into Oracle data storage.<br \/>\nHave fun with Oracle \ud83d\ude00<\/p>\n","protected":false},"excerpt":{"rendered":"<p>What is finally the primary objective of a database? Storing Data <img decoding=\"async\" src=\"plugins\/editors\/jce\/tiny_mce\/plugins\/emotions\/img\/smiley-laughing.gif\" alt=\"Laughing\" title=\"Laughing\" border=\"0\" \/><br \/>The question is, how Oracle makes it. For many beginners a confusing topic is<br \/>to get the picture between physical storage and logical one. So how does it works?<\/p>\n","protected":false},"author":7,"featured_media":11,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[199],"tags":[28,29,30,23,31,32,33,17,34,35,36],"type_dbi":[],"class_list":["post-2103","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hardware-storage","tag-assm","tag-blocks","tag-data-file","tag-dba","tag-extents","tag-lmts","tag-oracle-10g-to-8i","tag-oracle-11g","tag-segments","tag-storage","tag-tablespaces"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.2 (Yoast SEO v27.5) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Oracle Basics (2) - Data Storage - dbi Blog<\/title>\n<meta name=\"description\" content=\"Description of Oracle basic storage mechanisms. Shows difference between logical and physical storage by introducing concepts like tablespaces, data files or extents.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Oracle Basics (2) - Data Storage\" \/>\n<meta property=\"og:description\" content=\"Description of Oracle basic storage mechanisms. Shows difference between logical and physical storage by introducing concepts like tablespaces, data files or extents.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/\" \/>\n<meta property=\"og:site_name\" content=\"dbi Blog\" \/>\n<meta property=\"article:published_time\" content=\"2011-01-31T08:03:00+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/logical_physical_Storage.gif\" \/>\n\t<meta property=\"og:image:width\" content=\"908\" \/>\n\t<meta property=\"og:image:height\" content=\"622\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/gif\" \/>\n<meta name=\"author\" content=\"David Hueber\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"David Hueber\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"6 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/\"},\"author\":{\"name\":\"David Hueber\",\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/#\\\/schema\\\/person\\\/8873e20a98a02305870909f4e3d0088f\"},\"headline\":\"Oracle Basics (2) &#8211; Data Storage\",\"datePublished\":\"2011-01-31T08:03:00+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/\"},\"wordCount\":973,\"commentCount\":0,\"image\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/wp-content\\\/uploads\\\/sites\\\/2\\\/2022\\\/01\\\/logical_physical_Storage.gif\",\"keywords\":[\"ASSM\",\"Blocks\",\"Data file\",\"DBA\",\"Extents\",\"LMTS\",\"Oracle 10g to 8i\",\"Oracle 11g\",\"Segments\",\"Storage\",\"Tablespaces\"],\"articleSection\":[\"Hardware &amp; Storage\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/\",\"url\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/\",\"name\":\"Oracle Basics (2) - Data Storage - dbi Blog\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/wp-content\\\/uploads\\\/sites\\\/2\\\/2022\\\/01\\\/logical_physical_Storage.gif\",\"datePublished\":\"2011-01-31T08:03:00+00:00\",\"author\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/#\\\/schema\\\/person\\\/8873e20a98a02305870909f4e3d0088f\"},\"description\":\"Description of Oracle basic storage mechanisms. Shows difference between logical and physical storage by introducing concepts like tablespaces, data files or extents.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#primaryimage\",\"url\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/wp-content\\\/uploads\\\/sites\\\/2\\\/2022\\\/01\\\/logical_physical_Storage.gif\",\"contentUrl\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/wp-content\\\/uploads\\\/sites\\\/2\\\/2022\\\/01\\\/logical_physical_Storage.gif\",\"width\":908,\"height\":622},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/oracle-basics-2-data-storage\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Oracle Basics (2) &#8211; Data Storage\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/#website\",\"url\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/\",\"name\":\"dbi Blog\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/#\\\/schema\\\/person\\\/8873e20a98a02305870909f4e3d0088f\",\"name\":\"David Hueber\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/fc07284dbd5667f0bed32b0d8d64076ab885746973ea1b5c4e69c6fa7074cf59?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/fc07284dbd5667f0bed32b0d8d64076ab885746973ea1b5c4e69c6fa7074cf59?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/fc07284dbd5667f0bed32b0d8d64076ab885746973ea1b5c4e69c6fa7074cf59?s=96&d=mm&r=g\",\"caption\":\"David Hueber\"},\"description\":\"David Hueber has ten years of experience in infrastructure operation &amp; management, engineering, and optimization. He is specialized in Oracle technologies (engineering, backup and recovery, high availability, etc.), Service Management standards and Oracle infrastructure operation processes (Service Desk, Change Management, Capacity Planning, etc.). David Hueber is ITILv3 Service Operation Lifecycle certified and Linux LPIC-1 certified. He received a university degree in Informatics and Networks at the IUT Mulhouse, France. He also studied Information Systems at the Conservatoire National des Arts et M\u00e9tiers in Mulhouse, France. His branch-related experience covers Financial Services \\\/ Banking, Chemicals &amp; Pharmaceuticals, Transport &amp; Logistics, Retail, Food, etc.\",\"url\":\"https:\\\/\\\/www.dbi-services.com\\\/blog\\\/author\\\/david-hueber\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Oracle Basics (2) - Data Storage - dbi Blog","description":"Description of Oracle basic storage mechanisms. Shows difference between logical and physical storage by introducing concepts like tablespaces, data files or extents.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/","og_locale":"en_US","og_type":"article","og_title":"Oracle Basics (2) - Data Storage","og_description":"Description of Oracle basic storage mechanisms. Shows difference between logical and physical storage by introducing concepts like tablespaces, data files or extents.","og_url":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/","og_site_name":"dbi Blog","article_published_time":"2011-01-31T08:03:00+00:00","og_image":[{"width":908,"height":622,"url":"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/logical_physical_Storage.gif","type":"image\/gif"}],"author":"David Hueber","twitter_card":"summary_large_image","twitter_misc":{"Written by":"David Hueber","Est. reading time":"6 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#article","isPartOf":{"@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/"},"author":{"name":"David Hueber","@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8873e20a98a02305870909f4e3d0088f"},"headline":"Oracle Basics (2) &#8211; Data Storage","datePublished":"2011-01-31T08:03:00+00:00","mainEntityOfPage":{"@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/"},"wordCount":973,"commentCount":0,"image":{"@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#primaryimage"},"thumbnailUrl":"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/logical_physical_Storage.gif","keywords":["ASSM","Blocks","Data file","DBA","Extents","LMTS","Oracle 10g to 8i","Oracle 11g","Segments","Storage","Tablespaces"],"articleSection":["Hardware &amp; Storage"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/","url":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/","name":"Oracle Basics (2) - Data Storage - dbi Blog","isPartOf":{"@id":"https:\/\/www.dbi-services.com\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#primaryimage"},"image":{"@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#primaryimage"},"thumbnailUrl":"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/logical_physical_Storage.gif","datePublished":"2011-01-31T08:03:00+00:00","author":{"@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8873e20a98a02305870909f4e3d0088f"},"description":"Description of Oracle basic storage mechanisms. Shows difference between logical and physical storage by introducing concepts like tablespaces, data files or extents.","breadcrumb":{"@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#primaryimage","url":"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/logical_physical_Storage.gif","contentUrl":"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2022\/01\/logical_physical_Storage.gif","width":908,"height":622},{"@type":"BreadcrumbList","@id":"https:\/\/www.dbi-services.com\/blog\/oracle-basics-2-data-storage\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Accueil","item":"https:\/\/www.dbi-services.com\/blog\/"},{"@type":"ListItem","position":2,"name":"Oracle Basics (2) &#8211; Data Storage"}]},{"@type":"WebSite","@id":"https:\/\/www.dbi-services.com\/blog\/#website","url":"https:\/\/www.dbi-services.com\/blog\/","name":"dbi Blog","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.dbi-services.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8873e20a98a02305870909f4e3d0088f","name":"David Hueber","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/fc07284dbd5667f0bed32b0d8d64076ab885746973ea1b5c4e69c6fa7074cf59?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/fc07284dbd5667f0bed32b0d8d64076ab885746973ea1b5c4e69c6fa7074cf59?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/fc07284dbd5667f0bed32b0d8d64076ab885746973ea1b5c4e69c6fa7074cf59?s=96&d=mm&r=g","caption":"David Hueber"},"description":"David Hueber has ten years of experience in infrastructure operation &amp; management, engineering, and optimization. He is specialized in Oracle technologies (engineering, backup and recovery, high availability, etc.), Service Management standards and Oracle infrastructure operation processes (Service Desk, Change Management, Capacity Planning, etc.). David Hueber is ITILv3 Service Operation Lifecycle certified and Linux LPIC-1 certified. He received a university degree in Informatics and Networks at the IUT Mulhouse, France. He also studied Information Systems at the Conservatoire National des Arts et M\u00e9tiers in Mulhouse, France. His branch-related experience covers Financial Services \/ Banking, Chemicals &amp; Pharmaceuticals, Transport &amp; Logistics, Retail, Food, etc.","url":"https:\/\/www.dbi-services.com\/blog\/author\/david-hueber\/"}]}},"_links":{"self":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/2103","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/comments?post=2103"}],"version-history":[{"count":0,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/2103\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/media\/11"}],"wp:attachment":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/media?parent=2103"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/categories?post=2103"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/tags?post=2103"},{"taxonomy":"type","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/type_dbi?post=2103"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}