Обсуждение: Re: [INTERFACES] JDBC API to send SimpleQuery ('Q')?

Karthik Segpi <karthik.segpi@gmail.com> writes:
> I have the following Java code running in tomcat 7 using
> 'postgresql-9.3-1101-jdbc41.jar' driver.

> String str = "insert into tab1(a,b) values ('name', 'address');"
> Statement stmt = conn.createStatement();
> stmt.execute(str);

> Considering that this is *not* a PreparedStatement, I would have expected

> the driver to issue a Simple Query ('Q') instead of an ExtendedQuery ('P').
> However, when I print the incoming connection at my middleware (pgpool), I
> see the query being received is an ExtendedQuery ('P'). When I execute the
> same query in psql, it triggers a Simple Query ('Q') as expected.

You'd be better off asking about the behavior of the JDBC driver on
pgsql-jdbc, but offhand I see nothing unreasonable about it if they
choose to use extended query protocol exclusively.  Less code for
them to maintain, and it's not really less efficient as long as they
ensure messages get grouped into network packets appropriately.

(psql goes the other direction, and doesn't use extended protocol
at all, AFAIR.)

> What am I missing here? Are there any other settings that I need to tweak?

I think you could still force use of simple query mode by telling the
driver to use protocol version 2, but that has lots of downsides.

                        regards, tom lane

I have the following Java code running in tomcat 7 using 'postgresql-9.3-1101-jdbc41.jar' driver.

String str = "insert into tab1(a,b) values ('name', 'address');"

Statement stmt = conn.createStatement();

stmt.execute(str);

Considering that this is not a PreparedStatement, I would have expected the driver to issue a Simple Query ('Q') instead of an ExtendedQuery ('P'). However, when I print the incoming connection at my middleware (pgpool), I see the query being received is an ExtendedQuery ('P'). When I execute the same query in psql, it triggers a Simple Query ('Q') as expected. 

What am I missing here? Are there any other settings that I need to tweak? 

Thanks

On Fri, Apr 25, 2014 at 11:30 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Karthik Segpi <karthik.segpi@gmail.com> writes:
> I have the following Java code running in tomcat 7 using
> 'postgresql-9.3-1101-jdbc41.jar' driver.

> String str = "insert into tab1(a,b) values ('name', 'address');"
> Statement stmt = conn.createStatement();
> stmt.execute(str);

> Considering that this is *not* a PreparedStatement, I would have expected

> the driver to issue a Simple Query ('Q') instead of an ExtendedQuery ('P').
> However, when I print the incoming connection at my middleware (pgpool), I
> see the query being received is an ExtendedQuery ('P'). When I execute the
> same query in psql, it triggers a Simple Query ('Q') as expected.

You'd be better off asking about the behavior of the JDBC driver on
pgsql-jdbc, but offhand I see nothing unreasonable about it if they
choose to use extended query protocol exclusively.  Less code for
them to maintain, and it's not really less efficient as long as they
ensure messages get grouped into network packets appropriately.

(psql goes the other direction, and doesn't use extended protocol
at all, AFAIR.)

> What am I missing here? Are there any other settings that I need to tweak?

I think you could still force use of simple query mode by telling the
driver to use protocol version 2, but that has lots of downsides.

                        regards, tom lane