BEGIN(7)

✨ NAME ✨

BEGIN — start a transaction block. okay bestie, welcome to BEGIN(7) from the PostgreSQL 17.11 Documentation, and yes this is THE transaction-starting page 💅

🌸 SYNOPSIS 🌸

BEGIN [ WORK | TRANSACTION ] [ transaction_mode [, ...] ]

where transaction_mode is one of:

    ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED }
    READ WRITE | READ ONLY
    [ NOT ] DEFERRABLE

🦋 DESCRIPTION 🦋

Okay so, BEGIN initiates a transaction block — that is, all statements after a BEGIN command will be executed in a single transaction until an explicit COMMIT or ROLLBACK is given. no cap, that's the whole vibe.

By default (without BEGIN), PostgreSQL executes transactions in “autocommit” mode — that is, each statement is executed in its own transaction and a commit is implicitly performed at the end of the statement (if execution was successful, otherwise a rollback is done). autocommit is lowkey doing the most, one statement at a time 🫶

Statements are executed more quickly in a transaction block, because transaction start/commit requires significant CPU and disk activity. Execution of multiple statements inside a transaction is also useful to ensure consistency when making several related changes: other sessions will be unable to see the intermediate states wherein not all the related updates have been done. it's giving consistency when you've got several related changes 👑

If the isolation level, read/write mode, or deferrable mode is specified, the new transaction has those characteristics, as if SET TRANSACTION was executed.

🎀 PARAMETERS 🎀

• WORK
• TRANSACTION

Both are optional key words, bestie — they have no effect. literally just vibes 😭

Refer to SET TRANSACTION (SET_TRANSACTION(7)) for information on the meaning of the other parameters to this statement.

🔥 NOTES 🔥

• START TRANSACTION has the same functionality as BEGIN. same energy, different spelling ✨
• Use COMMIT or ROLLBACK to terminate a transaction block.
• Issuing BEGIN when already inside a transaction block will provoke a warning message. The state of the transaction is not affected. To nest transactions within a transaction block, use savepoints (see SAVEPOINT(7)). so don't try to inception it without savepoints, bestie 🙈
• For reasons of backwards compatibility, the commas between successive transaction_modes can be omitted.

🌈 EXAMPLES 🌈

To begin a transaction block:

BEGIN;

💜 COMPATIBILITY 💜

BEGIN is a PostgreSQL language extension. It is equivalent to the SQL-standard command START TRANSACTION, whose reference page contains additional compatibility information.

The DEFERRABLE transaction_mode is a PostgreSQL language extension.

Incidentally, the BEGIN key word is used for a different purpose in embedded SQL. You are advised to be careful about the transaction semantics when porting database applications. fr fr, porting girlies, pay attention to those transaction semantics ⚠️

🦋 SEE ALSO 🦋

• COMMIT(7)
• ROLLBACK(7)
• START TRANSACTION (START_TRANSACTION(7))
• SAVEPOINT(7)

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k bye bestie — PostgreSQL 17.11, 2026 edition, stay transactional 💖