[Fwd: rhdb-explain-2.0 suggested modification]

[Renato Gini <rgini at inwind dot it>]

Hi,
as suggested by Fernando Nasser, we repost our message to this e-mail 
address.
We also added the version of PostgreSql we used (previously forgotten); 
we will be glad to test your new version for PostgreSql v.8 when available!
Best regards

Renato Gini & Andrea Gerbo

Hello,
we are two italian developers; your tool is really great!!!
While trying to use it, we found a great loss of performances when the query has more than 1 or 2 components;
the memory was used at full and the execution time raised till we where forced to stop it by killing the process.
We made the attached modification to the source ExplainParserV73.java (using StringBuffer instead of String object) and the response is now a few seconds independently from the query complexity.

We are using Java 1.4.2_06 on a Linux (debian based) machine with PostgreSql vers.7.4
We hope our suggestion can be useful and we are available for any further question or specification.
Many thanks to you for your great work.

Renato Gini mailto:rgini@inwind.it
Andrea Gerbo mailto:andrea.gerbo@poste.it

Attachment: source modification

//ADDED
			StringBuffer tmp = new StringBuffer();
			// Parse the first row. Ignore all 'bad' rows.
			while (rs.next())
			{
				// Parse the first part (the dump)
				// The form of the dump is:
				//   .A '{'/
				//   <dump - may contain pairs of '{}'>
                               //   .A '}'

				// first row
				str = rs.getString(1);

				if (str.trim().startsWith("{"))
                              {
///REPLACED                              dump = str;/
					tmp.append(str);
					break;
                              }
				else
				{
					System.err.println("Ignoring: " + str);
					rs.next();
				}
			}
                      
			if (rs.isAfterLast())
				throw new ExplainException("Unexpected EXPLAIN output");
                      
			// If we get here, we know that first row has the first "{"

			// look for the "}" that closes the query dump
                      int braces = countChars(str, '{');
                      braces -= countChars(str, '}');
                      int ii=0;
                      while ((braces > 0) && (rs.next()))
                      {
                          str = rs.getString(1);
//REPLACED            	    dump += "\n" + str;
          		    tmp.append ("\n" + str);
                          braces += countChars(str, '{');
                          braces -= countChars(str, '}');
                      }
//ADDED
                      dump = tmp.toString();
			if (rs.isAfterLast())
				throw new ExplainException("Got nothing when QUERY PLAN expected");