Npgsql Exception while reading from stream, Postgres
Solution 1
conn = new NpgsqlConnection("Server=myserver;
User Id=postgres;
Password=somepw;
Database=somedb;
Pooling=false;
Timeout=300;
CommandTimeout=300");
I added the CommandTimeout
property to my connection string and it seems to be working now. Weird exception for a timeout error...
Solution 2
Please try the setting
KeepAlive = 300
The number of seconds of connection inactivity before Npgsql sends a keepalive query. Set to 0 (the default) to disable.
See the documentation.
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RDS_JAF
Updated on July 09, 2022Comments
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RDS_JAF almost 2 years
I am getting this error intermittently in my code. Sometimes it happens time-after-time-after-time. Sometimes it happens 1-out-of-10 times. I am not doing anything unique or special in my SQL unlike the other poster on StackOverflow who was doing a COPY command. All I am doing is SELECTs.
Here is the stack trace:
Exception while reading from stream at Npgsql.ReadBuffer.Ensure(Int32 count, Boolean dontBreakOnTimeouts) at Npgsql.NpgsqlConnector.DoReadMessage(DataRowLoadingMode dataRowLoadingMode, Boolean isPrependedMessage) at Npgsql.NpgsqlConnector.ReadMessageWithPrepended(DataRowLoadingMode dataRow LoadingMode) at Npgsql.NpgsqlConnector.ReadMessage(DataRowLoadingMode dataRowLoadingMode) at Npgsql.NpgsqlConnector.ReadExpecting[T]() at Npgsql.NpgsqlDataReader.NextResultInternal() at Npgsql.NpgsqlDataReader.NextResult() at Npgsql.NpgsqlCommand.Execute(CommandBehavior behavior) at Npgsql.NpgsqlCommand.ExecuteDbDataReaderInternal(CommandBehavior behavior) at Npgsql.NpgsqlCommand.ExecuteDbDataReader(CommandBehavior behavior) at System.Data.Common.DbCommand.ExecuteReader() at Npgsql.NpgsqlCommand.ExecuteReader() at JBetaFinder.Program.portfolioSimulation(String beginResult, String endResult) in c:\Users\j\Documents\Visual Studio 2013\Projects\JBetaFinder\JBetaFinder\Program.cs:line 571
Any suggestions on how to avoid this error? Is this a problem with Npgsql and postgres?
Here is my SQL Statement that seems to be the most problematic:
select leg1.trade_date, sum(p.qty) as totalqty, max(gas.net_change)*10000 as avggaschange, sum(((leg1.settlement_price - leg2.settlement_price) - (leg3.settlement_price - leg4.settlement_price))*qty*1000000) as spread_value_weight from quant_portfolio p inner join (select distinct trade_date, hub, product, strip, settlement_price, net_change from public.icecleared_gas where contract = 'H') leg1 on p.leg1 = leg1.strip inner join (select distinct trade_date, hub, product, strip, settlement_price, net_change from public.icecleared_gas where contract = 'H') leg2 on p.leg2 = leg2.strip and leg1.trade_date = leg2.trade_date inner join (select distinct trade_date, hub, product, strip, settlement_price, net_change from public.icecleared_gas where contract = 'H') leg3 on p.leg3 = leg3.strip and leg1.trade_date = leg3.trade_date inner join (select distinct trade_date, hub, product, strip, settlement_price, net_change from public.icecleared_gas where contract = 'H') leg4 on p.leg4 = leg4.strip and leg1.trade_date = leg4.trade_date inner join (select distinct trade_date, hub, product, strip, contract, settlement_price, net_change from public.icecleared_gas where contract = 'H') gas on gas.strip = (select min(leg1) from quant_portfolio where commodity = 'NG') and gas.trade_date = leg1.trade_date where p.commodity = 'NG' AND (leg1.trade_date>='xxx' and leg1.trade_date<='yyy') group by leg1.trade_date order by leg1.trade_date
I tried re-arranging the SQL to take out the sub-SELECTS and make them all joins; didn't help, same error.
Here is the C# code calling Npgsql:
query = new NpgsqlCommand(getFullQuantPortBeta.ToString().Replace("xxx", beginResult.ToString()).Replace("yyy", endResult.ToString()), conn); dr = query.ExecuteReader();//code does not get past this line! beta = 0; while (dr.Read()) { baselineData.Add(double.Parse(dr[2].ToString())); responseData.Add(double.Parse(dr[3].ToString())); if (baselineData.Count > 3) { Tuple<double, double> result = MathNet.Numerics.LinearRegression.SimpleRegression.Fit(baselineData.ToArray(), responseData.ToArray()); beta = result.Item2 * BETA_MULT; Console.WriteLine("WEIGHT BETA = " + beta); } } dr.Close();
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Dr Rob Lang over 7 yearsWelcome to Stack Overflow, please can you post the C# where you're calling Npgsql?
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Shay Rojansky over 7 yearsYour exception report is incomplete: you don't post the type of the exception, nor any inner exceptions (would probably contain the real problem). Please add those to your question.
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Click Ok almost 3 years"Weird exception for a timeout error" - the timeout error appears in the Inner Exception, probably "System.TimeoutException: Timeout during reading attempt"