Sql lock table while updating
ACID is an acronym that stands for Atomicity, Consistency, Isolation, and Durability.
Each of these properties is described in more detail below.
If you’re using the Citus extension to Postgres to shard database tables across multiple nodes, one more thing to take into consideration is that queries might get blocked on row-level locks on one of the shards on a distributed Citus worker node—and if that happens, then those queries would not show up in to get more information such as how long the query was running.
Locking is one of the mechanisms that Postgres uses to safely implement concurrent ACID transactions.
To make sure complex transactions can safely run at the same time, Postgre SQL uses several layers of locks to serialise changes to critical sections of the database.So, if a transaction violates the databases consistency rules, then the entire transaction will be rolled back.2.1.3 Isolation Isolation means that concurrent transactions, and the changes made within them, are not visible to each other until they complete.Sometimes you notice a command is taking awfully long, but the process is not actually doing anything.In that case it might be waiting for a lock and you should have a look at to finish.