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How does PostgreSQL clean up dead tuples?
PostgreSQL rather creates what is called a “dead tuple”. If there is no more dependency on those tuples by the running transactions, PostgreSQL cleans it up using a process called VACUUM. The space used up by those tuples are sometimes called “Bloat”.
How does vacuum process work in PostgreSQL database?
Whenever any transaction begins, it operates in its own snapshot of the database, that means whenever any record is deleted, PostgreSQL instead of actually deleting it, it creates a dead row (called dead tuple). VACUUM process thereby helps in optimising the the resource usage, in a way also helping in the database performance.
What happens when a record is deleted in PostgreSQL?
Whenever a record is deleted, it does not create an extra space in the system. PostgreSQL rather creates what is called a “dead tuple”. If there is no more dependency on those tuples by the running transactions, PostgreSQL cleans it up using a process called VACUUM. The space used up by those tuples are sometimes called “Bloat”.
Why is last autovacuum null in PostgreSQL?
If your bloated table does not show up here, n_dead_tup is zero and last_autovacuum is NULL, you might have a problem with the statistics collector. If the bloated table is right there on top, but last_autovacuum is NULL, you might need to configure autovacuum to be more aggressive so that it gets done with the table.
What’s the difference between inserted and live tuples in Postgres?
The Postgres documentation doesn’t provide answers either: Why do my stats show 213,324,422 inserted tuples, but only 124,510,280 live tuples? (3,087,919 dead tuples) The PG Admin documentation is also unclear about this. It further says that Tuples Inserted displays the number of tuples inserted into the database within the last week.
What does live and Dead mean in PostgreSQL?
Representing the number of live and dead rows (tuples) in the table. Find those functions in the manual. Dead rows are deleted rows that will later be reused for new rows from INSERT s or UPDATE s (the space, not the data).