Re: Patch: Implement failover on libpq connect level.

On Tue, Nov 1, 2016 at 6:54 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>That's the wrong syntax. If you look in
> https://www.postgresql.org/docs/devel/static/libpq-connect.html under
> "32.1.1.2. Connection URIs", it gives an example of how to include a
> slash in a pathname. You have to use %2F, or else the URL parser will
> think you're starting a new section of the URI.
>I believe this works fine if you use the correct syntax.

Sorry that was a mistake from me. Now it appears fine.

>
> Starting program: /home/mithun/libpqbin/bin/./psql
> postgres://%2fhome%2fmithun:5555/postgres -U mithun1
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib64/libthread_db.so.1".
> psql: could not connect to server: No such file or directory
> Is the server running locally and accepting
> *connections on Unix domain socket "/home/mithun/.s.PGSQL.5555"*?

Accidentally when testing further on this line I found a crash when invalid
encoding "%2" (not recognised as hexa) was used.
Test:

> Starting program: /home/mithun/libpqbin/bin/*./psql
> postgres://%2home%2mithun:5555/postgres -U mithun1*

[Thread debugging using libthread_db enabled]

Using host libthread_db library "/lib64/libthread_db.so.1".

> Program received signal SIGSEGV, Segmentation fault.

0x00007ffff7bb8d4f in PQpass (conn=0x68aaa0) at fe-connect.c:5582

5582 password = conn->connhost[conn->whichhost].password;

Missing separate debuginfos, use: debuginfo-install
> glibc-2.17-106.el7_2.6.x86_64 ncurses-libs-5.9-13.20130511.el7.x86_64
> readline-6.2-9.el7.x86_64

There can be PGconn which have no connhost.
exposed API's PQpass, PQreset->connectDBStart access conn->connhost without
checking whether it is set.

>That output seems fine to me. In a real connection string, you're not
>likely to have so many duplicated addresses, and it's good for the
>error message to make clear which addresses were tried and what
>happened for each one.

Agree, Thanks.

--
Thanks and Regards
Mithun C Y
EnterpriseDB: http://www.enterprisedb.com