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What is disable and enable trigger in PostgreSQL?
To disable a trigger, you use the ALTER TABLE DISABLE TRIGGER statement:
- ALTER TABLE table_name DISABLE TRIGGER trigger_name | ALL.
- ALTER TABLE employees DISABLE TRIGGER log_last_name_changes;
- ALTER TABLE employees DISABLE TRIGGER ALL;
How do I disable enable trigger?
DML triggers defined on tables can be also be disabled or enabled by using ALTER TABLE. Changing the trigger by using the ALTER TRIGGER statement enables the trigger.
How do I drop a constraint in PostgreSQL?
The syntax for dropping a unique constraint in PostgreSQL is: ALTER TABLE table_name DROP CONSTRAINT constraint_name; table_name. The name of the table to modify.
How to update large tables in PostgreSQL without downtime?
If you have a table with hundreds of millions of rows you will find that simple operations, such as adding a column or changing a column type, are hard to do in a timely manner. Doing these kind of operations without downtime is an even harder challenge.
How can i Improve my query in PostgreSQL?
You could improve queries by better managing the table indexes. Indexes help to identify the disk location of rows that match a filter. If there is no index, Postgres will have to do a sequential scan of the whole table. The more rows there are, the more time it will take. If you add an index, the query will be faster.
When to remove indexes in PostgreSQL to improve performance?
Sometimes indexes are not used because there are not enough rows in the table. So if the table is new, you should wait a few weeks before removing them. It’s always possible to do better, and spend more time to improve performance.
What happens when you update a column in PostgreSQL?
In this blog post I will try to outline guidelines and strategies to minimize the impact in table availability while managing large data sets. When you update a value in a column, Postgres writes a whole new row in the disk, deprecates the old row and then proceeds to update all indexes.