What are database extents?

What are database extents?

An extent consists of a collection of contiguous pages that store data for a given table. When you create a table, the database server allocates a fixed amount of space to contain the data to be stored in that table. When this space fills, the database server must allocate space for additional storage. …

What is data page in database?

A database page is an 8 KB chunk of data. When you insert any data into a SQL Server database, it saves the data to a series of 8 KB pages inside the data file. If multiple data files exist within a filegroup, SQL Server allocates pages to all data files based on a round-robin mechanism.

What are Oracle pages?

A page is a unit of storage whose size is configurable on a system-wide, database-wide, or conglomerate-specific basis. …

What are the types of tablespaces in Oracle?

There are three types of tablespaces:

  • Permanent. You use permanent tablespaces to store your user and application data.
  • Undo. A database running in automatic undo management mode transparently creates and manages undo data in the undo tablespace.
  • Temporary.

What is Pctused and Pctfree in Oracle?

PCTFREE is a parameter used to find how much space should be left in a database block for future updates. PCTUSED is a parameter helps Oracle to find when it should consider a database block to be empty enough to be added to the freelist.

What is segment and extent?

Introduction to Data Blocks, Extents, and Segments The next level of logical database space is an extent. An extent is a specific number of contiguous data blocks allocated for storing a specific type of information. The level of logical database storage greater than an extent is called a segment.

What are data pages?

A DataPage is a web interface that allows you to view, edit, manage and password-protect data stored in your online database. DataPages allow you to easily interact with your data on a web page, while securely hosting your database in the cloud.

How do you create a data page?

Creating a data page

  1. In the header of Dev Studio, click Create Data Model Data Page .
  2. On the Create Data Page page, in the Data Page Record Configuration section, in the Label field, enter a name for the top-level page that this rule creates and maintains.
  3. Click Create and open.

What is a page in Apex?

A single Visualforce page. All pages must be wrapped inside a single page component tag. Use this component to get user input for a controller method that does not correspond to a field on an sObject.

What is table space in Oracle?

An Oracle database consists of one or more logical storage units called tablespaces, which collectively store all of the database’s data. Each tablespace in an Oracle database consists of one or more files called datafiles, which are physical structures that conform to the operating system in which Oracle is running.

What is PGA in Oracle?

A Program Global Area (PGA) is a memory region that contains data and control information for a server process. It is nonshared memory created by Oracle Database when a server process is started. The PGA is used to process SQL statements and to hold logon and other session information.

What is Pctfree and Pctused?

When to use regular size pages in Oracle?

In Oracle Database 11 g Release 2 (, if there are not enough large pages configured on the system, then regular sized pages will be used to allocate SGA memory.

Can you query Oracle 10g database for pagination?

In fact, Database pagination is a common requirement of Java web developers, especially dealing with the largest datasets. In this article, we will see how to query Oracle 10g database for pagination or how to retrieve data using paging from Oracle.

What are the types of dialog pages in Oracle?

Oracle Application Express supports two types of dialog pages: Modal Dialog – A modal dialog is an overlay window positioned within the within the same browser window. A modal dialog remains active and focused until the user has finished with it and closes it.

How does Oracle allocate memory in large pages?

In Oracle Database 11 g Release 2 ( and later releases, Oracle allocates as much of the SGA as it can in large pages, and if it runs out, it will allocate the rest of the SGA using regular sized pages. This can cause the instance to create additional shared memory segments for the SGA, but the total SGA size will be unchanged.