Some numbers that indicate PostgreSQL performance using JDBC to query and insert data. All of the tests done on the same quiescent machine.

Read performance

A simple program to run reads looks as follows:

/**
 * @author <a href="mailto:jal@etc.to">Frits Jalvingh</a>
 * Created on 8-6-17.
 */
import java.sql.*;
import java.util.*;

public class PgReadTest {
   public static void main(String args[]) {
      try {
         Class.forName("org.postgresql.Driver");
         String dbURL = "jdbc:postgresql://localhost:5432/staging_12_tst";
         Properties parameters = new Properties();
         parameters.put("user", "jal");
         parameters.put("password", "jal");

         Connection conn = DriverManager.getConnection(dbURL, parameters);

         conn.setAutoCommit(false);                // Important

         String query = "select * from staging.boekingdetail";
         long lStartTime = System.currentTimeMillis();
         int size = 0;
         try(PreparedStatement ps = conn.prepareStatement(query)) {
            ps.setFetchSize(65536);
            try(ResultSet rs = ps.executeQuery()) {
               int cols = rs.getMetaData().getColumnCount();
               while(rs.next()) {
                  for(int i = 1; i <= cols; i++) {
                     Object val = rs.getObject(i);
                  }
                  size++;
               }
            }
         }

         long lEndTime = System.currentTimeMillis();
         long difference = lEndTime - lStartTime;
         double rps = (double) size / (difference / 1000);
         System.out.println("Read " + size + " rows in " + difference + " milliseconds, " + rps + " rows per second");
      } catch(Exception e) {
         e.printStackTrace();
      }
   }
}

Important parameters are fetch size and autocommit. When autocommit is ON (which it is by default) the JDBC driver exhibits horrible behavior. It read all rows in memory before returning from rs.next, causing huge processing delays and OOM if many rows are present.

The important thing here is:

Set autocommit = false, and set fetch size reasonably high so that the driver can stream rows from the server.

Numbers, with fetchsize=65536:

Read 24179781 rows in 32614 milliseconds, 755618.15625 rows per second
Read 24179781 rows in 32953 milliseconds, 755618.15625 rows per second

Fetchsize = 32768

Read 24179781 rows in 33048 milliseconds, 732720.6363636364 rows per second
Read 24179781 rows in 32957 milliseconds, 755618.15625 rows per second

Fetchsize=1024*1024:

Read 24179781 rows in 48519 milliseconds, 503745.4375 rows per second
Read 24179781 rows in 48561 milliseconds, 503745.4375 rows per second

Insert tests

A simple program to test for inserts:

/**
 * @author <a href="mailto:jal@etc.to">Frits Jalvingh</a>
 * Created on 8-6-17.
 */
import java.sql.*;
import java.util.*;

public class PgInsertTest {
   public static void main(String args[]) {
      try {
         Class.forName("org.postgresql.Driver");
         String dbURL = "jdbc:postgresql://localhost:5432/datavault_12_tst";
         Properties parameters = new Properties();
         parameters.put("user", "jal");
         parameters.put("password", "jal");

         Connection conn = DriverManager.getConnection(dbURL, parameters);
         conn.setAutoCommit(false);                // Important

         String query = "insert into datavault.h_boekingdetail(id_h,source_system_id,organisation_id,load_dts,boekingdetailid) values(?,?,?,?,?)";
         long lStartTime = System.currentTimeMillis();
         int size = 0;
         int commitSize = 50_000;
         int commitCount = 0;
         int batchSize = 0;
         int batchCount = 0;

         try(PreparedStatement ps = conn.prepareStatement(query)) {
            long now = System.currentTimeMillis();
            for(int row = 0; row < 1_000_000; row++) {
               ps.setInt(1, row + 1000_000);
               ps.setInt(2, 1);
               ps.setInt(3, 12);
               ps.setTimestamp(4, new Timestamp(now));
               ps.setString(5, "boe" + row + "kingdetail" + row);
               size++;
               commitCount++;
               batchCount++;

               if(batchSize <= 0) {
                  ps.executeUpdate();
                  if(commitCount > commitSize) {
                     commitCount = 0;
                     conn.commit();
                  }
               } else {
                  batchCount++;
                  ps.addBatch();
                  if(batchCount >= batchSize) {
                     ps.executeBatch();
                     batchCount = 0;

                     if(commitCount > commitSize) {
                        commitCount = 0;
                        conn.commit();
                     }
                  }
               }
            }

            if(batchSize > 0 && batchCount > 0) {
               ps.executeBatch();
            }
         }
         conn.commit();

         long lEndTime = System.currentTimeMillis();
         long difference = lEndTime - lStartTime;
         double rps = (double) size / (difference / 1000);
         System.out.println("Inserted " + size + " rows in " + difference + " milliseconds, " + rps + " rows per second");
      } catch(Exception e) {
         e.printStackTrace();
      }
   }
}

Numbers: without batching and commit size 50.000:

Inserted 1000000 rows in 29732 milliseconds, 34482.75862068965 rows per second
Inserted 1000000 rows in 28303 milliseconds, 35714.28571428572 rows per second

With commit size 100.000:

Inserted 1000000 rows in 29037 milliseconds, 34482.75862068965 rows per second

With commitsize 50.000 and batch size 1000:

Inserted 1000000 rows in 14029 milliseconds, 71428.57142857143 rows per second
Inserted 1000000 rows in 14292 milliseconds, 71428.57142857143 rows per second

With commit size 50.000 and batch size 10.000:

Inserted 1000000 rows in 14322 milliseconds, 71428.57142857143 rows per second
Inserted 1000000 rows in 14272 milliseconds, 71428.57142857143 rows per second

Removing primary key and all indices from the table

Commit size 50.000 and batch size 10.000

Inserted 1000000 rows in 7500 milliseconds, 142857.14285714287 rows per second
Inserted 1000000 rows in 7410 milliseconds, 142857.14285714287 rows per second

A two-fold performance increase.

Same settings but setting table to UNLOGGED:

Inserted 1000000 rows in 7025 milliseconds, 142857.14285714287 rows per second
Inserted 1000000 rows in 6940 milliseconds, 166666.66666666666 rows per second

Enabling "dangerous" options in PostgreSQL

Switching off fsync and full_page_writes has no effect on performance.

Inserting from the database itself, using pgsql

The following PGSQL method:

CREATE or replace function test() returns void AS $$
DECLARE
    count integer;
BEGIN
    for count in 1..1000000 loop
        insert into datavault.h_test(id_h,source_system_id,organisation_id,load_dts,boekingdetailid)
        values(count, 1, 12, now(), 'boe' || count || 'king' || count);
    end loop;
END;
$$ LANGUAGE plpgsql;

can be executed as:

select test();
commit;

and returns in 4 seconds, which means 250.000 rows per second. This seems to be an upper limit, and is less than half the speed Oracle manages (see below).

Similar checks on Oracle

Writing the same in Oracle is quite a lot faster. Without indexes and PK, but with full transaction logging the performance is:

Inserted 1000000 rows in 1072 milliseconds, 1000000.0 rows per second
Inserted 24000000 rows in 47155 milliseconds, 510638.2978723404 rows per second

PostgreSQL performance tests