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help / color / mirror / Atom feedFrom: Dave Cramer <davecramer@postgres.rocks>
To: Manav Kumar <mkumar@yugabyte.com>
Cc: pgsql-jdbc@lists.postgresql.org
Subject: Re: Don't see CLOSE packet been sent
Date: Sun, 7 Dec 2025 08:50:55 -0500
Message-ID: <CADK3HHLxR3b4_9jvT8UwUYVDkFmMb4MP3yXZvjtn4036VG_heA@mail.gmail.com> (raw)
In-Reply-To: <CAPhCW+9ZL9dmE54bm+EW9i5yRQqrtRkTt_AQ9_4U-vBD1tpyzw@mail.gmail.com>
References: <CAPhCW+_N8emtusnO5B4bj3U3iFwH6BRSHMQZAexSAv3n7dkOog@mail.gmail.com>
<CAPhCW+9ZL9dmE54bm+EW9i5yRQqrtRkTt_AQ9_4U-vBD1tpyzw@mail.gmail.com>
Please post this on github as you will get more traction
https://github.com/pgjdbc/pgjdbc/issues
Does seem like a bug though.
Dave Cramer
www.postgres.rocks
On Sat, 6 Dec 2025 at 06:35, Manav Kumar <mkumar@yugabyte.com> wrote:
> Hi Team,
> Writing to ask for a follow up. Can someone please clarify. I only see
> CLOSE been sent by driver when server returns an error message 'prepared
> statement does not exist".
>
> Thanks
> Manav
>
> On Thu, Dec 4, 2025 at 7:07 PM Manav Kumar <mkumar@yugabyte.com> wrote:
>
>> Hi Team,
>> Wrote a simple below application to understand nature of CLOSE packet.
>> But i don't see the JDBC sending CLOSE packet. Any ideas what i can do
>> see CLOSE packet.
>> I'm compiling with:
>> javac -classpath /home/manavkumar/postgresql-42.7.1.jar sendClose.java &&
>> \
>> java -cp .:/home/manavkumar/postgresql-42.7.1.jar sendClose
>>
>> ```import java.sql.*;
>>
>> public class sendClose {
>>
>> public static void main(String[] args) {
>> Connection connection = null;
>> PreparedStatement pstmt1 = null, pstmt2 = null;
>>
>> try {
>> // prepareThreshold=1 is crucial here
>> connection = DriverManager.getConnection("jdbc:postgresql://
>> 10.150.3.175:5433/yugabyte?prepareThreshold=1", "yugabyte","yugabyte");
>>
>> // ---------------------------------------------------------
>> // CHANGE 1: Use placeholders (?)
>> // This forces the driver to use Extended Query Protocol (Parse/Bind)
>> // and create a named statement (e.g., "S_1") on the server.
>> // ---------------------------------------------------------
>> pstmt1 = connection.prepareStatement("insert into t_ values (?, ?)");
>> pstmt1.setInt(1, 1);
>> pstmt1.setInt(2, 2);
>> // Execute twice to ensure the driver switches to server-prepare mode
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> pstmt1.execute();
>> // ---------------------------------------------------------
>> // CHANGE 2: Close the statement
>> // The driver now marks "S_1" as closed internally and queues the packet.
>> // ---------------------------------------------------------
>> pstmt1.close();
>>
>> System.out.println("Statement 1 closed. Sending Statement 2 to flush the
>> buffer...");
>>
>> // ---------------------------------------------------------
>> // CHANGE 3: Send ANY other traffic
>> // The driver will attach the buffered "CLOSE S_1" packet
>> // to the front of this new request.
>> // ---------------------------------------------------------
>> pstmt2 = connection.prepareStatement("SELECT 1");
>> pstmt2.execute();
>> pstmt2.close();
>>
>> connection.close();
>> }
>> catch (Exception e) {
>> e.printStackTrace();
>> }
>> }
>> }
>>
>> ```
>>
>
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To: pgsql-jdbc@postgresql.org
Cc: davecramer@postgres.rocks, mkumar@yugabyte.com, pgsql-jdbc@lists.postgresql.org
Subject: Re: Don't see CLOSE packet been sent
In-Reply-To: <CADK3HHLxR3b4_9jvT8UwUYVDkFmMb4MP3yXZvjtn4036VG_heA@mail.gmail.com>
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