Re: jdbc bug/feature?

Marko,

I checked in a fix for this problem. It should appear in 7.3RC2 this
weekend.

thanks,
--Barry

Marko Štrukelj wrote:
>
> Hello,
>
> There is a bug (I say) or a lack of proper functionality in JDBC driver
> regarding batch updates.
>
> The following code is expected to work by some library that I use and it
> does work with inet tds driver for M$ SQL server. It however does not
> work with the latest jdbc from cvs or anything older than that either.
>
>
> PreparedStatements st = c.prepareStatement("insert into my_table
> (field1, field2) values (?, ?)");
>
> // we have say 30 inserts to do
> Iterator it = inserts.iterator();
> int i=0;
> while(it.hasNext()) {
>
> // there is a maximum batch size of 15, so we must periodically
> execute it
> if(i==batchMax) {
> st.executeBatch();
> i=0;
>
> // the problem - after this call a PreparedStatement is
> empty and consequtive binds fail
> }
>
> Object [] binds = (Object [])it.next();
> st.setString(binds[0]);
> st.setString(binds[1]);
> st.addBatch();
> i++;
> }
>
>
>
> Upon some research I discovered the problem and found a very simple
> solution:
>
> In org.postgresql.jdbc2.AbstractJdbc2Statement:
>
> public int[] executeBatch() throws SQLException
> {
> System.out.println("### executeBatch");
> if (batch == null)
> batch = new Vector();
> int size = batch.size();
> int[] result = new int[size];
> int i = 0;
>
> // >>> added
> // save m_binds and m_sqlFragments because
> executeUpdate(String) will destroy them
> String [] oldFrags = m_sqlFragments;
> Object [] oldMBinds = m_binds;
> // <<
>
> try
> {
> for (i = 0;i < size;i++)
> result[i] =
> this.executeUpdate((String)batch.elementAt(i));
>
> }
> catch (SQLException e)
> {
> int[] resultSucceeded = new int[i];
> System.arraycopy(result, 0, resultSucceeded, 0, i);
>
> PBatchUpdateException updex =
> new
> PBatchUpdateException("postgresql.stat.batch.error",
>
> new Integer(i), batch.elementAt(i), resultSucceeded);
>
> updex.setNextException(e);
>
> throw updex;
> }
> finally
> {
> batch.removeAllElements();
> // >> added
> // restore m_binds and m_sqlFragments
> m_sqlFragments = oldFrags;
> m_binds = oldMBinds;
> // <<
> }
> return result;
> }
>
>
>
>
> Please consider this as a bug, and patch it in cvs. I did not test this
> very well, so the described patch may possibly cause some incosistencies
> somewhere - the people who wrote that class will know best. It does work
> for my case though.
>
>
> And thanks for PostgreSQL, I've just started using it and I love it.
>
>
>
> - Marko
>