Обсуждение: Row values

Hello,
I am writing my first trigger in C for PostgreSQL. It compiles Ok, and
added it to the database using CREATE TRIGGER. But when I try to fire
it, psql simply says 'The connection was lost". What I don't know is how
to get the row values (not the name fields) from tg_trigger.
The code is:

...

    TriggerData *trigdata = (TriggerData *) fcinfo->context;

...

    strcpy(query, "INSERT INTO visita_log VALUES ('");
    strcat(query, trigdata->tg_trigger->tgargs[0]);
    strcat(query, "','");
    strcat(query, trigdata->tg_trigger->tgargs[1]);
    strcat(query, "','");
    strcat(query, trigdata->tg_trigger->tgargs[2]);
    strcat(query, "','");
    strcat(query, trigdata->tg_trigger->tgargs[3]);
    strcat(query, "',");
    strcat(query, trigdata->tg_trigger->tgargs[4]);
    strcat(query, ",'");
    strcat(query, trigdata->tg_trigger->tgargs[5]);
    strcat(query, "');");


    SPI_exec(query, 0);

...

I don't know if tgargs[] return the row values or the field names.

Thanks.


Juan

On Fri, Jul 02, 2004 at 07:36:50AM -0300, Juan Jose Costello Levien wrote:

> I am writing my first trigger in C for PostgreSQL. It compiles Ok, and
> added it to the database using CREATE TRIGGER. But when I try to fire
> it, psql simply says 'The connection was lost".

Most likely the server process crashed.  See the server log and the core
file for details to debug your function.

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
La web junta la gente porque no importa que clase de mutante sexual seas,
tienes millones de posibles parejas. Pon "buscar gente que tengan sexo con
ciervos incendiánse", y el computador dirá "especifique el tipo de ciervo"
(Jason Alexander)

Alvaro,

Sorry, but, where are the log file and core you mentioned? I tried
/var/log/postgresql but is in 0 file size.

TIA


>On Fri, Jul 02, 2004 at 07:36:50AM -0300, Juan Jose Costello Levien wrote:
>
>
>
>>I am writing my first trigger in C for PostgreSQL. It compiles Ok, and
>>added it to the database using CREATE TRIGGER. But when I try to fire
>>it, psql simply says 'The connection was lost".
>>
>>
>
>Most likely the server process crashed.  See the server log and the core
>file for details to debug your function.
>
>
>

Juan Jose Costello Levien <jcostello@datafull.com> writes:
> I don't know if tgargs[] return the row values or the field names.

Neither --- it's the (fixed) arguments you used in the CREATE TRIGGER
command.  You'll need to do something involving extracting field values
from the tuple that is passed to the trigger, instead.

I'd suggest looking in the contrib/ modules for examples of triggers
written in C.

            regards, tom lane

On Fri, Jul 02, 2004 at 09:56:43AM -0300, Juan Jose Costello Levien wrote:
> Alvaro,
>
> Sorry, but, where are the log file and core you mentioned? I tried
> /var/log/postgresql but is in 0 file size.

Your server may be misconfigured (most linux distros are).  Make sure
your init script does not redirect postmaster's (or pg_ctl's)
stdout/stderr to /dev/null.  Also make sure that if you are using
syslog, the syslog server is configured to save the messages somewhere
useful, by checking the facility Postgres uses (configurable) and where
does syslog save messages from this facility.

The core file, on the other hand, should be somewhere in
/var/lib/pgsql/data/base (if you haven't changed PGDATA), _unless_ the
server runs under a core 0-byte limit (under bash, ulimit -c will tell
you).

Hope this helps,

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"Java is clearly an example of a money oriented programming"  (A. Stepanov)