CODEWITHSUNDEEP
javamultithreadingpostgresqljdbcthread-safety
Basil Bourque
Basil Bourque

Reputation: 338785

Is Postgres JDBC driver `org.postgresql.ds.PGSimpleDataSource` thread-safe?

In the JDBC driver for Postgres, is PGSimpleDataSource thread-safe?

That is, if I use a cached singleton instance of that class, can I pass it out to multiple threads? Each thread may be calling getConnection at the same moment. The documentation makes no mention of thread-safety.

I am trying to avoid both (a) making multi-threaded calls on a Connection and (b) using a connection pool, as discussed in the doc. I want a separate Connection for each servlet thread.

Upvotes: 1

Views: 4983

Answers (1)

Mark Rotteveel
Mark Rotteveel

Reputation: 109015

I'm assuming you won't be changing the data source configuration on multiple threads, because then it isn't thread-safe. You can inspect the source code yourself, on https://github.com/pgjdbc/pgjdbc, the specific code for getConnection is in BaseDataSource:

public Connection getConnection(String user, String password) throws SQLException {
    try {
      Connection con = DriverManager.getConnection(getUrl(), user, password);
      if (LOGGER.isLoggable(Level.FINE)) {
        LOGGER.log(Level.FINE, "Created a {0} for {1} at {2}", new Object[]{getDescription(), user, getUrl()});
      }
      return con;
    } catch (SQLException e) {
      LOGGER.log(Level.SEVERE, "Failed to create a {0} for {1} at {2}: {3}",
          new Object[]{getDescription(), user, getUrl(), e});
      throw e;
    }
}

In other words, it is a thin wrapper around DriverManager. DriverManager itself is thread-safe, so then it becomes a question if org.postgresql.Driver is thread-safe. I don't have time to try to verify that, but lets just say it would be really surprising if that wasn't thread-safe (and otherwise world-wide applications would fail with all kinds of strange race-conditions, etc).

As a side note: PGSimpleDataSource does not provide connection pooling, you might want to consider whether that is right for your use case.

Upvotes: 5

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