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Are triggers thread safe?
You can fire trigger programs in a multithreaded job. The same threadsafety restrictions apply to trigger programs as to any other code that runs in a multithreaded job. Data manipulation language (DML) statements are threadsafe.
Is Postgres thread safe?
The PostgreSQL JDBC Driver is thread safe. Consequently, if your application uses multiple threads then you do not have to worry about complex algorithms to ensure that only one uses the database at any time.
How trigger works in PostgreSQL?
A “trigger” is defined as any event that sets a course of action in a motion. In PostgreSQL, if you want to take action on specific database events, such as INSERT, UPDATE, DELETE, or TRUNCATE, then trigger functionality can be useful as it will invoke the required function on defined events.
Does PostgreSQL support triggers?
PostgreSQL offers both per-row triggers and per-statement triggers. With a per-row trigger, the trigger function is invoked once for each row that is affected by the statement that fired the trigger.
What is true for triggers and rules in PostgreSQL?
If checks for valid values are required, and in the case of an invalid value an error message should be generated, it must be done by a trigger. On the other hand, a trigger that is fired on INSERT on a view can do the same as a rule: put the data somewhere else and suppress the insert in the view.
How to create a trigger function in PostgreSQL?
Summary: in this tutorial, you will learn how to use the PostgreSQL CREATE TRIGGER statement to create a trigger. First, create a trigger function using CREATE FUNCTION statement. Second, bind the trigger function to a table by using CREATE TRIGGER statement.
When to fire constraint trigger in Postgresql 9.0?
Constraint triggers must be AFTER ROW triggers. They can be fired either at the end of the statement causing the triggering event, or at the end of the containing transaction; in the latter case they are said to be deferred. A pending deferred-trigger firing can also be forced to happen immediately by using SET CONSTRAINTS.
Why are trigger functions opaque in PostgreSQL Version 7.3?
This can result in significant speedups in statements that modify many rows, if the trigger only needs to be fired for a few of the rows. In PostgreSQL versions before 7.3, it was necessary to declare trigger functions as returning the placeholder type opaque, rather than trigger.
How often does trigger on delete occur in PostgreSQL?
For example, a DELETE that affects 10 rows will cause any ON DELETE triggers on the target relation to be called 10 separate times, once for each deleted row.