Does creating readOnly connections, when possible, free up resources in Postgres?
I have an API server and I'm trying to be conscientious managing Postgres's resources carefully. On the client side, I have a Hikari Pool. Usually when I need a connection, I simply create a default read/write connection, even if I don't plan to make any updates or inserts or hold any locks. But most of my database connections are in fact read-only. I saw that when you create a JDBC connection, you can specify readOnly=true. Would doing so somehow help Postgres manage its other connections? Perhaps Postgres, knowing that a connection is readOnly and will never even attempt to do an update, will free up some internal resources for other connections. Is this accurate?
Does creating readOnly connections, when possible, free up resources in Postgres?
(resending to remove HTML formatting) I have an API server and I'm trying to be conscientious managing Postgres's resources carefully. On the client side, I have a Hikari Pool. Usually when I need a connection, I simply create a default read/write connection, even if I don't plan to make any updates or inserts or hold any locks. But most of my database connections are in fact read-only. I saw that when you create a JDBC connection, you can specify readOnly=true. Would doing so somehow help Postgres manage its other connections? Perhaps Postgres, knowing that a connection is readOnly and will never even attempt to do an update, will free up some internal resources for other connections. Is this accurate?
Java's org.postgresql.util.PSQLState is missing common PostgreSQL Error Codes
In my Java API server, I am using SERIALIZABLE transaction isolation mode, so I'm specially handling the error code of "40001 serialization_failure", which can occur often. I'm getting the error code String using SQLException's getSQLState() function. Therefore I was surprised to see that the Java enum org.postgresql.util.PSQLState does not include this error code. PSQLState code: https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/util/PSQLState.java PSQLState documentation: https://jdbc.postgresql.org/development/privateapi/org/postgresql/util/PSQLState.html The 40001 serialization_failure error is listed here: https://www.postgresql.org/docs/11/errcodes-appendix.html It seems like this should be added to the pgjdbc Java enum. Is there a reason it's not in there?
