What is the difference between the two? The protocol on the surface looks different, but I would like to understand what is really different between the two and why they are not equivalent.
Difference between 2PC (2 phase commit) and 2 PL (2 phase locking)
3.1k views Asked by user855 At
1
There are 1 answers
Related Questions in DATABASE
- php Variable name must change in for loop
- register_shutdown_function is not getting called
- Query returning zero rows despite entries existing
- Retrieving *number* pages by page id
- Automatically closing tags in form input?
- How to resize images with PHP PARSE SDK
- how to send email from localhost using codeigniter?
- Mariadb max Error while sending QUERY packet PID
- Multiusers login redirect different page in php
- Imaginary folder when I use "DirectoryIterator" in PHP?
Related Questions in DISTRIBUTED
- php Variable name must change in for loop
- register_shutdown_function is not getting called
- Query returning zero rows despite entries existing
- Retrieving *number* pages by page id
- Automatically closing tags in form input?
- How to resize images with PHP PARSE SDK
- how to send email from localhost using codeigniter?
- Mariadb max Error while sending QUERY packet PID
- Multiusers login redirect different page in php
- Imaginary folder when I use "DirectoryIterator" in PHP?
Related Questions in PAXOS
- php Variable name must change in for loop
- register_shutdown_function is not getting called
- Query returning zero rows despite entries existing
- Retrieving *number* pages by page id
- Automatically closing tags in form input?
- How to resize images with PHP PARSE SDK
- how to send email from localhost using codeigniter?
- Mariadb max Error while sending QUERY packet PID
- Multiusers login redirect different page in php
- Imaginary folder when I use "DirectoryIterator" in PHP?
Related Questions in TWO-PHASE-COMMIT
- php Variable name must change in for loop
- register_shutdown_function is not getting called
- Query returning zero rows despite entries existing
- Retrieving *number* pages by page id
- Automatically closing tags in form input?
- How to resize images with PHP PARSE SDK
- how to send email from localhost using codeigniter?
- Mariadb max Error while sending QUERY packet PID
- Multiusers login redirect different page in php
- Imaginary folder when I use "DirectoryIterator" in PHP?
Popular Questions
- How do I undo the most recent local commits in Git?
- How can I remove a specific item from an array in JavaScript?
- How do I delete a Git branch locally and remotely?
- Find all files containing a specific text (string) on Linux?
- How do I revert a Git repository to a previous commit?
- How do I create an HTML button that acts like a link?
- How do I check out a remote Git branch?
- How do I force "git pull" to overwrite local files?
- How do I list all files of a directory?
- How to check whether a string contains a substring in JavaScript?
- How do I redirect to another webpage?
- How can I iterate over rows in a Pandas DataFrame?
- How do I convert a String to an int in Java?
- Does Python have a string 'contains' substring method?
- How do I check if a string contains a specific word?
Popular Tags
Trending Questions
- UIImageView Frame Doesn't Reflect Constraints
- Is it possible to use adb commands to click on a view by finding its ID?
- How to create a new web character symbol recognizable by html/javascript?
- Why isn't my CSS3 animation smooth in Google Chrome (but very smooth on other browsers)?
- Heap Gives Page Fault
- Connect ffmpeg to Visual Studio 2008
- Both Object- and ValueAnimator jumps when Duration is set above API LvL 24
- How to avoid default initialization of objects in std::vector?
- second argument of the command line arguments in a format other than char** argv or char* argv[]
- How to improve efficiency of algorithm which generates next lexicographic permutation?
- Navigating to the another actvity app getting crash in android
- How to read the particular message format in android and store in sqlite database?
- Resetting inventory status after order is cancelled
- Efficiently compute powers of X in SSE/AVX
- Insert into an external database using ajax and php : POST 500 (Internal Server Error)
2 Phase lockingis a mechanism implemented within a single database instance to achieve serializeable isolation level. Serializeable transaction level is the strongest isolation where even with parallely executing transactions, the end result is same as if the transactions where executed serially. It works as follows:Whenever the transaction wants to update an object/row, it must acquire a write/exclusive lock. When transactions wants to read an object/row, it must acquire a read/shared lock. Instead of releasing the lock immediately after each query, the locks must be held till the end of the transaction(commit or abort). So while the transaction is being executed, the number of locks held by the transaction expand/grow. (Read/write lock behavior is similar to any other reader/writer locking mechanisms, so not discussing here)
At the end of the transaction, the locks are released and number of locks held by the transactions shrinks.
Since the locks are acquired in one phase and released in another phase i.e., there are no lock releases in acquire phase and no new lock acquire in release phase, this is called 2 phase locking.
2 phase commitis an algorithm for implementing distributed transaction across multiple database instances to ensure all nodes either commit or abort the transaction.It works by having coordinator(could be a separate service or library within the application initiating the transaction) issue two requests - PREPARE to all nodes in phase 1 and COMMIT(if all nodes returned OK in PREPARE phase) or ABORT(if any node returned NOT OK in PREPARE PHASE) to all nodes in phase 2.
TLDR:
2 phase locking- for serializable isolation within a single database instance2 phase commit- atomic commit across multiple nodes of a distributed database/datastores