Thread: long delay with binary data on ubuntu and 9.4.1

When executed in psql on Ubuntu 14.04 LTS (ubuntu/trusty64) the query "select bindata from rcfiledata where id = 106"
hangsfrom 6-12 seconds before completing. On OS X, it takes a few milliseconds. This happens with the package available
frompostgresql.org for 9.4 and with a compiled version of 9.4.1. 

All tests were with the server running on OS X. Ubuntu was running in vagrant/virtualbox. The attached filedata.sql
containsa dump of the table.  

The same problem happens when executed in a program using libpq.That program is included in pgtest.c. When breaking in
gdbwhile hung, the backtrace is: 

(gdb) bt
#0  0x00007ffff72ab110 in __poll_nocancel () at ../sysdeps/unix/syscall-template.S:81
#1  0x000000000040bb9e in pqSocketCheck ()
#2  0x000000000040c480 in pqWaitTimed ()
#3  0x000000000040a809 in PQgetResult ()
#4  0x000000000040aafe in PQexecFinish ()
#5  0x0000000000402c4b in main (argc=1, argv=0x7fffffffe648) at pgtest.c:9

Mark Lilback <Mark.Lilback@mail.wvu.edu> wrote:

> [slow response time]

> All tests were with the server running on OS X. Ubuntu was
> running in vagrant/virtualbox.

Nothing in your report suggests any PostgreSQL bug.  You might find
useful suggestions on pages like this:

https://stefanwrobel.com/how-to-make-vagrant-performance-not-suck

On my Ubuntu machine (running on bare hardware rather than in a
vagrant/virtualbox under OS X) that runs in about 5 ms.  You might
want to check that vagrant is honoring the TCP_NODELAY setting
(which disables the Nagle algorithm).

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company