Differences between Oracle PGA and SGA and the use of latch and lock

Source: Internet
Author: User

1. What is the difference between PGA and SGA?

SGA is the global area of the system, and PGA is the global area of the process.

Oracle is running, and SGA is the memory structure of oracle, such as putting databuf and share pool, allocating at oracle startup, and recycling at oracle shutdown.

When a PGA is used to connect an oracle database, oracle opens a memory zone for this user only. After the user is disconnected, oracle recycles the memory.

2. What are the application scenarios of latch and lock?

Lock table-level locks and row-level locks can also be divided into shared locks and exclusive locks, that is, they are locked during comparison.

Latch is a memory lock. For example, if a data block is loaded into the memory, the lock is used when multiple sessions compete for the block in the memory.

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.