NullPointerException in ExecuteNonQuery for DROP TABLE IF EXISTS

[fdsmax]

Hi,

The ExecteNonQuery throws NullPointerException for the below query. Any solutions or pointers to fix this?

DROP TABLE IF EXISTS myschema."TableName";

Npgsql.PostgresException (0x80004005): XX000: NullPointerException in io.crate.analyze.AbstractDropTableAnalyzedStatement.tableIdent(AbstractDropTableAnalyzedStatement.java:48) at Npgsql.NpgsqlConnector.<>cDisplayClass161_0.<gReadMessageLong|0>d.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Npgsql.NpgsqlConnector.<>cDisplayClass161_0.<gReadMessageLong|0>d.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Threading.Tasks.ValueTask`1.get_Result() at Npgsql.NpgsqlDataReader.d46.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Npgsql.NpgsqlDataReader.NextResult() at Npgsql.NpgsqlCommand.d100.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Npgsql.NpgsqlCommand.d__92.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Npgsql.NpgsqlCommand.ExecuteNonQuery()

I am using nuget packages: Npgsql.CrateDb 1.2.3 net462 Npgsql.CrateFork 1.0.1 net462

Against latest crate db 3.2.6.

Thanks and regards, Diwakar

[fdsmax]

Hi, sorry I mistakenly closed this defect because of red-herring while testing the above query. I have thought the quotes in the query caused an issue. However, without quotes too the nullpointer exception is thrown from ExecuteNonQuery:

DROP TABLE IF EXISTS myschema.TableName;

If I remove 'IF EXISTS' from the query then it works ok. I think this is a defect. Therefore, I have reopened it. Pl let me know if you could re-produce the problem.

[mschwoebel]

@diwakarpp Hi ive tried to reproduce this problem. Ive created a small snippet and it worked without problems.

using Npgsql;
using Npgsql.CrateDb;

namespace Sample.CrateDb.CrateDropTable
{
    class Program
    {
        static void Main(string[] args)
        {
            NpgsqlDatabaseInfo.RegisterFactory(new CrateDbDatabaseInfoFactory());

            //Try dropping not existing table
            using (var con = OpenConnection())
            using (var cmd = new NpgsqlCommand("DROP TABLE IF EXISTS myschema.abcdefg;", con))
            {
                var r = cmd.ExecuteNonQuery();
            }

            //Create Table and drop
            CreateTestTable();
            using (var con = OpenConnection())
            using (var cmd = new NpgsqlCommand("DROP TABLE IF EXISTS myschema.TableName;", con))
            {
                var r = cmd.ExecuteNonQuery();
            }

            //Create Table and drop with quotes
            CreateTestTable();
            using (var con = OpenConnection())
            using (var cmd = new NpgsqlCommand("DROP TABLE IF EXISTS myschema.\"tablename\";", con))
            {
                var r = cmd.ExecuteNonQuery();
            }
        }

        const string DefaultConnectionString = "Server=localhost;User ID=crate;Database=npgsql_tests;Timeout=0;Command Timeout=0;Port=5435";

        private static NpgsqlConnection OpenConnection(string connectionString = null)
        {
            if (connectionString == null)
                connectionString = DefaultConnectionString;
            var conn = new NpgsqlConnection(connectionString);

            conn.Open();

            return conn;
        }

        private static void CreateTestTable()
        {
            using (var con = OpenConnection())
            {
                using (var cmd = con.CreateCommand())
                {
                    cmd.CommandText = @"create table if not exists myschema.tablename(
                        id integer primary key,
                        string_field string,
                        boolean_field boolean,
                        byte_field byte,
                        short_field short,
                        integer_field integer,
                        long_field long,
                        float_field float,
                        double_field double,
                        timestamp_field timestamp,
                        object_field object(strict) as (""inner"" string),
                        ip_field ip,
                        geo_point_field geo_point,
                        geo_shape_field geo_shape
                      ) clustered by (id) into 1 shards with (number_of_replicas=0, column_policy = 'dynamic')";

                    cmd.ExecuteNonQuery();
                }
            }
        }
    }
}

Can you please check if this snippet is running for you? if not can you please provide a code snippet.

Thanks and regards, Marc

[mfussenegger]

Based on the error

Npgsql.PostgresException (0x80004005): XX000: NullPointerException in io.crate.analyze.AbstractDropTableAnalyzedStatement.tableIdent(AbstractDropTableAnalyzedStatement.java:48)

I think this was a bug in CrateDB itself and not in the npgsql client. 3.2.6. is quite old and I couldn't reproduce the NPE with current versions so I'm going to close this for now.