Re: JDBC slow performance on resultSet iteration?

Just an quick info update: i'm using the postgresql-9.2-1003-jdbc4 driver

On 2013/11/05, at 16:09, Rui Pedro Leal wrote:

> Hello everyone,
>
> I'm having slow JDBC performance on iterating a resultSet obtained from a somewhat simple query.
>
> The query, although using PostGIS functions, is pretty straight forward:
>
> SELECT _id, _spatial_type, ST_AsBinary(_geometry), _attribute, _count, _references, countpersons, countfatals, countdrunks, density
> FROM accidents_5
> WHERE (_geometry && ST_MakeEnvelope(-126.60644531250001,26.43122806450644,-63.369140625,52.96187505907603, 4326) )
> ORDER BY _pk_id
>
> The results are the following:
> - Executing the query directly from pgAdmin: ~2807ms
> - Executing from JVM + JDBC: 4184ms
>
> The code i'm executing is pretty much standard:
>
> -------------------- code --------------------
>
> public static void main(final String[] args) throws Exception {
>
> String sql = "SELECT _id, _spatial_type, ST_AsBinary(_geometry), _attribute, _count, _references, countpersons, countfatals, countdrunks, density";
> sql += " FROM accidents_5";
> sql += " WHERE (_geometry && ST_MakeEnvelope(-126.60644531250001,26.43122806450644,-63.369140625,52.96187505907603, 4326) )";
> sql += " ORDER BY _pk_id";
>
> System.out.println(sql);
>
> Long time = System.currentTimeMillis();
> try {
> Connection connection = DataStoreInfo.getDataStores().get(0);
> connection.setAutoCommit(false);
>
> System.out.println("[QUERY " + Thread.currentThread().getId()
> + "] - connection in "
> + (System.currentTimeMillis() - time) + "ms.");
>
> Statement st = connection.createStatement(
> ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY,
> ResultSet.CLOSE_CURSORS_AT_COMMIT);
> st.setFetchSize(250);
>
> System.out.println("[QUERY " + Thread.currentThread().getId()
> + "] - statement in " + (System.currentTimeMillis() - time)
> + "ms.");
>
> ResultSet resultSet = st.executeQuery(sql);
>
> System.out.println("[QUERY " + Thread.currentThread().getId()
> + "] - done in " + (System.currentTimeMillis() - time)
> + "ms.");
>
> GeometryFactory geofact = new GeometryFactory(new PrecisionModel(),4326);
> WKBReader wkbReader = new WKBReader(geofact);
>
> String id;
> String spatialType;
> Geometry geometry;
> String attribute;
> Long count;
> String reference;
> Map<String, Double> properties;
> String granularSynthString = "GranularSynthesis";
>
> while (resultSet.next()) {
> id = resultSet.getString(1);
> spatialType = resultSet.getString(2);
>
> // geometry = wkbReader.read(resultSet.getBytes(3)); // ignored the WKBReader and the results are about the same.
> attribute = resultSet.getString(4);
> count = resultSet.getLong(5);
> reference = resultSet.getString(6);
>
> properties = new HashMap<String, Double>();
> Double aux = resultSet.getDouble(7);
> properties.put("countpersons", aux);
> aux = resultSet.getDouble(8);
> properties.put("countfatals", aux);
> aux = resultSet.getDouble(9);
> properties.put("countdrunks", aux);
> aux = resultSet.getDouble(10);
> properties.put("density", aux);
> }
>
> System.out.println("[QUERY " + Thread.currentThread().getId()
> + "] - done & iterated in "
> + (System.currentTimeMillis() - time) + "ms.");
>
> resultSet.close();
> st.close();
> connection.commit();
> connection.close();
> } catch (SQLException exception) {
> exception.printStackTrace();
> // } catch (ParseException exception) { // ignored from WKBreader
> // exception.printStackTrace();
> }
>
> System.out.println("[End " + Thread.currentThread().getId()
> + "] - done in " + (System.currentTimeMillis() - time) + "ms.");
> }
>
> -------------------- end code --------------------
>
> Although i'm executing this on slow MacbookPro (2.6 core duo, 2Gbs RAM but SSD) and have a 9.1.2 postgres, i've also tested this on a recent retina MBP and the ratio between pgAdmin and JDBC execution is similar.
>
> Is this expected? Can someone point if i'm doing something terrible wrong?
>
> I'm not concerned about the query performance per-se (i know it CAN be optimized), but the differences just using JDBC and iterating the resultSet are really annoying.
>
> Thanks in advance for any help.
>
> Kind regards,
>
> Rui Leal
>
>