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Description

PostgreSQL error 25P04, "transaction timeout," indicates that an active database transaction has exceeded its configured time limit and has been aborted. This typically occurs when a database operation takes too long to complete, preventing the transaction from committing within the allowed timeframe, often due to long-running queries or resource contention.

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Error Message

transaction timeout

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Known Causes

3 known causes

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Excessive Query Execution Time

A specific query within the transaction took an unexpectedly long time to execute, surpassing the `statement_timeout` or `idle_in_transaction_session_timeout`.

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Database Contention or Locking

The transaction was blocked by other concurrent operations holding necessary locks, preventing it from progressing and committing within the timeout period.

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Aggressive Timeout Configuration

The configured `statement_timeout` or `idle_in_transaction_session_timeout` values are set too low for the application's typical workload, causing legitimate operations to time out prematurely.

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Solutions

3 solutions available

1. Increase `statement_timeout` for Specific Sessions easy

Temporarily increase the timeout for a specific session or transaction.

1

Connect to your PostgreSQL database using a client (e.g., `psql`).

2

Before executing a long-running query or starting a transaction that might exceed the default timeout, set the `statement_timeout` parameter for the current session. A value of `0` disables the timeout. Set it to a sufficiently large number of milliseconds (e.g., `3600000` for 1 hour).

SET statement_timeout = '3600000'; -- 1 hour in milliseconds

3

Execute your long-running query or transaction.

4

Optionally, reset the timeout to its previous value or default after the operation completes.

RESET statement_timeout;

2. Adjust Global `statement_timeout` in `postgresql.conf` medium

Increase the default statement timeout for all sessions by modifying the PostgreSQL configuration file.

1

Locate your `postgresql.conf` file. The location varies depending on your operating system and PostgreSQL installation. Common locations include `/etc/postgresql/<version>/main/postgresql.conf` or within the PostgreSQL data directory.

2

Open `postgresql.conf` in a text editor with administrative privileges.

3

Find the line containing `statement_timeout`. If it's commented out (starts with `#`), uncomment it. If it doesn't exist, add it.

#statement_timeout = 0       # 1s-1h; 0 disables
statement_timeout = '3600000' # Example: 1 hour in milliseconds

4

Save the `postgresql.conf` file.

5

Reload the PostgreSQL configuration. This can be done without restarting the server.

pg_ctl reload -D /path/to/your/data/directory

6

Alternatively, if you are managing PostgreSQL with `systemd`:

sudo systemctl reload postgresql

3. Optimize Long-Running Queries and Transactions advanced

Address the root cause by improving the performance of your database operations.

1

Identify the specific queries or transactions that are timing out. You can use PostgreSQL's logging features to capture slow queries. Enable `log_min_duration_statement` in `postgresql.conf` to log queries exceeding a certain duration.

log_min_duration_statement = '5s' # Log queries longer than 5 seconds

2

Analyze the execution plans of these slow queries using `EXPLAIN ANALYZE`. Look for sequential scans on large tables, inefficient join strategies, or missing indexes.

EXPLAIN ANALYZE SELECT * FROM your_table WHERE your_column = 'some_value';

3

Create appropriate indexes on columns used in `WHERE` clauses, `JOIN` conditions, and `ORDER BY` clauses.

CREATE INDEX idx_your_table_your_column ON your_table (your_column);

4

Rewrite queries to be more efficient. This might involve simplifying complex joins, using subqueries effectively, or leveraging PostgreSQL's built-in functions.

5

For long-running transactions, consider breaking them down into smaller, manageable units or using asynchronous processing if possible.

6

Ensure your database statistics are up-to-date by running `ANALYZE` (or `VACUUM ANALYZE`) regularly, especially after significant data changes.

ANALYZE your_table;

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Related Errors

5 related errors

PostgreSQL Error 25P04: Transaction Timeout Error