Thread: potential bug in trigger with boolean params

potential bug in trigger with boolean params

From
Szymon Guz
Date:
Hi,
I was trying to create a trigger with parameters. I've found a potential bug when the param is boolean.

Here is code replicating the bug:

CREATE TABLE x(x TEXT);

CREATE OR REPLACE FUNCTION trigger_x() RETURNS TRIGGER AS $$
BEGIN
        RETURN NEW;
END; $$ LANGUAGE PLPGSQL;

CREATE TRIGGER trig_x_text BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x('text');
CREATE TRIGGER trig_x_int BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(10);
CREATE TRIGGER trig_x_float BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(42.0);
CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(true);

ERROR:  syntax error at or near "true"
LINE 1: ... INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(true);


I've already checked that on:
'PostgreSQL 9.0.1, compiled by Visual C++ build 1500, 32-bit'
'PostgreSQL 9.0.4 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-46), 64-bit'


If this is intended behavior, then the documentation doesn't say anything about that.
The only information is that:

TG_ARGV[]

Data type array of text; the arguments from the CREATE TRIGGER statement.

but the below line throws the same error:

CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x( true::text );

while this obviously works: 

SELECT true::text;

and this works as well:

CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x('true');
regards
Szymon



Re: potential bug in trigger with boolean params

From
tv@fuzzy.cz
Date:
> Hi,
> I was trying to create a trigger with parameters. I've found a potential
> bug
> when the param is boolean.
>
> Here is code replicating the bug:
>
> CREATE TABLE x(x TEXT);
>
> CREATE OR REPLACE FUNCTION trigger_x() RETURNS TRIGGER AS $$
> BEGIN
>         RETURN NEW;
> END; $$ LANGUAGE PLPGSQL;
>
> CREATE TRIGGER trig_x_text BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE
> trigger_x('text');
> CREATE TRIGGER trig_x_int BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE
> trigger_x(10);
> CREATE TRIGGER trig_x_float BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE trigger_x(42.0);
> CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE
> trigger_x(true);
>
> ERROR:  syntax error at or near "true"
> LINE 1: ... INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(true);

The docs clearly state what the valid values are and the literal 'true' is
not one of them (TRUE is). See this:

http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html

regards
Tomas



Re: potential bug in trigger with boolean params

From
Szymon Guz
Date:


On 11 May 2011 10:56, <tv@fuzzy.cz> wrote:
> Hi,
> I was trying to create a trigger with parameters. I've found a potential
> bug
> when the param is boolean.
>
> Here is code replicating the bug:
>
> CREATE TABLE x(x TEXT);
>
> CREATE OR REPLACE FUNCTION trigger_x() RETURNS TRIGGER AS $$
> BEGIN
>         RETURN NEW;
> END; $$ LANGUAGE PLPGSQL;
>
> CREATE TRIGGER trig_x_text BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE
> trigger_x('text');
> CREATE TRIGGER trig_x_int BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE
> trigger_x(10);
> CREATE TRIGGER trig_x_float BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE trigger_x(42.0);
> CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE
> trigger_x(true);
>
> ERROR:  syntax error at or near "true"
> LINE 1: ... INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(true);

The docs clearly state what the valid values are and the literal 'true' is
not one of them (TRUE is). See this:

http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html

regards
Tomas


Well... no.

In the link you've provided there is something different:

 
Valid literal values for the "true" state are:

TRUE
't'
'true'
'y'
'yes'
'on'
'1'

so I could use 'true'... and this doesn't work.

And SQL is not case sensitive... but I will check it for you anyway:

CREATE TRIGGER trig_x_2 BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(TRUE);

ERROR:  syntax error at or near "TRUE"
LINE 1: ... INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(TRUE);

regards
Szymon

Re: potential bug in trigger with boolean params

From
Andreas Joseph Krogh
Date:
På onsdag 11. mai 2011 kl 10:56:19 skrev <tv@fuzzy.cz>:
> > Hi,
> > I was trying to create a trigger with parameters. I've found a potential
> > bug
> > when the param is boolean.
> >
> > Here is code replicating the bug:
> >
> > CREATE TABLE x(x TEXT);
> >
> > CREATE OR REPLACE FUNCTION trigger_x() RETURNS TRIGGER AS $$
> > BEGIN
> >         RETURN NEW;
> > END; $$ LANGUAGE PLPGSQL;
> >
> > CREATE TRIGGER trig_x_text BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE
> > trigger_x('text');
> > CREATE TRIGGER trig_x_int BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE
> > trigger_x(10);
> > CREATE TRIGGER trig_x_float BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE trigger_x(42.0);
> > CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE
> > trigger_x(true);
> >
> > ERROR:  syntax error at or near "true"
> > LINE 1: ... INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(true);
>
> The docs clearly state what the valid values are and the literal 'true' is
> not one of them (TRUE is). See this:
>
> http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html

What are you trying to accomplish? "CREATE OR REPLACE FUNCTION trigger_x()" does not declare any formal-parameters, so
callingit with arguments doesn't make sense. I'm surprised creating the other triggers didn't produce an error stating
"Nofunction defined with the name trigger_ix and the given argument-type". 

--
Andreas Joseph Krogh <andreak@officenet.no>
Senior Software Developer / CTO
Public key: http://home.officenet.no/~andreak/public_key.asc
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Re: potential bug in trigger with boolean params

From
Andres Freund
Date:
On Wednesday, May 11, 2011 11:01:56 AM Andreas Joseph Krogh wrote:
> På onsdag 11. mai 2011 kl 10:56:19 skrev <tv@fuzzy.cz>:
> > > CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > > PROCEDURE
> > > trigger_x(true);
> > The docs clearly state what the valid values are and the literal 'true'
> > is not one of them (TRUE is). See this:
> >
> > http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html
>
> What are you trying to accomplish? "CREATE OR REPLACE FUNCTION trigger_x()"
> does not declare any formal-parameters, so calling it with arguments
> doesn't make sense. I'm surprised creating the other triggers didn't
> produce an error stating "No function defined with the name trigger_ix and
> the given argument-type".
Read the docs. Parameters for triggers are not passed as normal function
parameters. Thats why you access them via via TG_ARGV in plpgsql.

The grammar accepts only a very limited amount of parameters there:


Re: potential bug in trigger with boolean params

From
Andres Freund
Date:
On Wednesday, May 11, 2011 11:21:34 AM Andres Freund wrote:
> On Wednesday, May 11, 2011 11:01:56 AM Andreas Joseph Krogh wrote:
> > På onsdag 11. mai 2011 kl 10:56:19 skrev <tv@fuzzy.cz>:
> > > > CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > > > PROCEDURE
> > > > trigger_x(true);
> > >
> > > The docs clearly state what the valid values are and the literal 'true'
> > > is not one of them (TRUE is). See this:
> > >
> > > http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html
> >
> > What are you trying to accomplish? "CREATE OR REPLACE FUNCTION
> > trigger_x()" does not declare any formal-parameters, so calling it with
> > arguments doesn't make sense. I'm surprised creating the other triggers
> > didn't produce an error stating "No function defined with the name
> > trigger_ix and the given argument-type".
>
> Read the docs. Parameters for triggers are not passed as normal function
> parameters. Thats why you access them via via TG_ARGV in plpgsql.
>
> The grammar accepts only a very limited amount of parameters there:
Err....

TriggerFuncArg:        Iconst            {                char buf[64];                snprintf(buf, sizeof(buf), "%d",
$1);               $$ = makeString(pstrdup(buf));            }        | FCONST                                { $$ =
makeString($1);}        | Sconst                                { $$ = makeString($1); }        | BCONST
               { $$ = makeString($1); }        | XCONST                                { $$ = makeString($1); }
|ColId                                { $$ = makeString($1); } 

That is integers, floating point, strings, bitstrings, hexstrings and column references (???).

How that exact list came to exist I do not know.

Andres


Re: potential bug in trigger with boolean params

From
Szymon Guz
Date:


On 11 May 2011 11:01, Andreas Joseph Krogh <andreak@officenet.no> wrote:
På onsdag 11. mai 2011 kl 10:56:19 skrev <tv@fuzzy.cz>:
> > Hi,
> > I was trying to create a trigger with parameters. I've found a potential
> > bug
> > when the param is boolean.
> >
> > Here is code replicating the bug:
> >
> > CREATE TABLE x(x TEXT);
> >
> > CREATE OR REPLACE FUNCTION trigger_x() RETURNS TRIGGER AS $$
> > BEGIN
> >         RETURN NEW;
> > END; $$ LANGUAGE PLPGSQL;
> >
> > CREATE TRIGGER trig_x_text BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE
> > trigger_x('text');
> > CREATE TRIGGER trig_x_int BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE
> > trigger_x(10);
> > CREATE TRIGGER trig_x_float BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE trigger_x(42.0);
> > CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE
> > PROCEDURE
> > trigger_x(true);
> >
> > ERROR:  syntax error at or near "true"
> > LINE 1: ... INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(true);
>
> The docs clearly state what the valid values are and the literal 'true' is
> not one of them (TRUE is). See this:
>
> http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html

What are you trying to accomplish? "CREATE OR REPLACE FUNCTION trigger_x()" does not declare any formal-parameters, so calling it with arguments doesn't make sense. I'm surprised creating the other triggers didn't produce an error stating "No function defined with the name trigger_ix and the given argument-type".


That's how you define trigger function. Later you can use params when defining trigger.

regards
Szymon

Re: potential bug in trigger with boolean params

From
Andreas Joseph Krogh
Date:
<p>På onsdag 11. mai 2011 kl 11:30:51 skrev <strong>Szymon Guz</strong> <<a
href="mailto:mabewlun@gmail.com">mabewlun@gmail.com</a>>:<blockquotestyle="border-left: 1px solid rgb(204, 204,
204);margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br /><br /><div class="gmail_quote">On 11 May 2011 11:01, Andreas
JosephKrogh <span dir="ltr"><<a href="mailto:andreak@officenet.no">andreak@officenet.no</a>></span> wrote:<br
/><blockquoteclass="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> På onsdag 11.
mai2011 kl 10:56:19 skrev <<a href="mailto:tv@fuzzy.cz">tv@fuzzy.cz</a>>:<br /><div><div> </div><div
class="h5">>> Hi,<br /> > > I was trying to create a trigger with parameters. I've found a potential<br />
>> bug<br /> > > when the param is boolean.<br /> > ><br /> > > Here is code replicating the
bug:<br/> > ><br /> > > CREATE TABLE x(x TEXT);<br /> > ><br /> > > CREATE OR REPLACE FUNCTION
trigger_x()RETURNS TRIGGER AS $$<br /> > > BEGIN<br /> > >         RETURN NEW;<br /> > > END; $$
LANGUAGEPLPGSQL;<br /> > ><br /> > > CREATE TRIGGER trig_x_text BEFORE INSERT ON x FOR EACH ROW EXECUTE<br
/>> > PROCEDURE<br /> > > trigger_x('text');<br /> > > CREATE TRIGGER trig_x_int BEFORE INSERT ON x
FOREACH ROW EXECUTE<br /> > > PROCEDURE<br /> > > trigger_x(10);<br /> > > CREATE TRIGGER
trig_x_floatBEFORE INSERT ON x FOR EACH ROW EXECUTE<br /> > > PROCEDURE trigger_x(42.0);<br /> > > CREATE
TRIGGERtrig_x_bool BEFORE INSERT ON x FOR EACH ROW EXECUTE<br /> > > PROCEDURE<br /> > >
trigger_x(true);<br/> > ><br /> > > ERROR:  syntax error at or near "true"<br /> > > LINE 1: ...
INSERTON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(true);<br /> ><br /> > The docs clearly state what the valid
valuesare and the literal 'true' is<br /> > not one of them (TRUE is). See this:<br /> ><br /> > <a
href="http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html"
target="_blank">http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.html</a><br/></div></div> What are you
tryingto accomplish? "CREATE OR REPLACE FUNCTION trigger_x()" does not declare any formal-parameters, so calling it
witharguments doesn't make sense. I'm surprised creating the other triggers didn't produce an error stating "No
functiondefined with the name trigger_ix and the given argument-type".<br /><br /></blockquote><div> </div><div>That's
howyou define trigger function. Later you can use params when defining trigger.</div></div></blockquote><p>Pardon my
ignorance:-)<br/><br /><span style="font-family: monospace; font-size: 10px;">--<br /> Andreas Joseph Krogh
<andreak@officenet.no><br/> Senior Software Developer / CTO<br /> Public key:
http://home.officenet.no/~andreak/public_key.asc<br/>
------------------------+---------------------------------------------+<br/> OfficeNet AS            | The most
difficultthing in the world is to |<br /> Rosenholmveien 25       | know how to do a thing and to watch         |<br />
1414Trollåsen          | somebody else doing it wrong, without       |<br /> NORWAY                  | comment.       
                           |<br /> Org.nr: NO 981 479 076  |                                             |<br />      
                 |                                             |<br /> Tlf:    +47 24 15 38 90 |                       
                    |<br /> Fax:    +47 24 15 38 91 |                                             |<br /> Mobile: +47
909 56 963 |                                             |<br />
------------------------+---------------------------------------------+<br/></span> 

Re: potential bug in trigger with boolean params

From
Andres Freund
Date:
On Wednesday, May 11, 2011 11:50:35 AM Szymon Guz wrote:
> On 11 May 2011 11:29, Andres Freund <andres@anarazel.de> wrote:
> > On Wednesday, May 11, 2011 11:21:34 AM Andres Freund wrote:
> > > On Wednesday, May 11, 2011 11:01:56 AM Andreas Joseph Krogh wrote:
> > > > På onsdag 11. mai 2011 kl 10:56:19 skrev <tv@fuzzy.cz>:
> > > > > > CREATE TRIGGER trig_x_bool BEFORE INSERT ON x FOR EACH ROW
> > > > > > EXECUTE PROCEDURE
> > > > > > trigger_x(true);
> > > > >
> > > > > The docs clearly state what the valid values are and the literal
> >
> > 'true'
> >
> > > > > is not one of them (TRUE is). See this:
> > > > >
> > > > > http://www.postgresql.org/docs/9.0/interactive/datatype-boolean.htm
> > > > > l
> > > >
> > > > What are you trying to accomplish? "CREATE OR REPLACE FUNCTION
> > > > trigger_x()" does not declare any formal-parameters, so calling it
> > > > with arguments doesn't make sense. I'm surprised creating the other
> > > > triggers didn't produce an error stating "No function defined with
> > > > the name trigger_ix and the given argument-type".
> > >
> > > Read the docs. Parameters for triggers are not passed as normal
> > > function parameters. Thats why you access them via via TG_ARGV in
> > > plpgsql.
> >
> > > The grammar accepts only a very limited amount of parameters there:
> > Err....
> >
> > TriggerFuncArg:
> >                        Iconst
> >
> >                                {
> >
> >                                        char buf[64];
> >                                        snprintf(buf, sizeof(buf), "%d",
> >
> > $1);
> >
> >                                        $$ = makeString(pstrdup(buf));
> >
> >                                }
> >                        |
> >                        | FCONST
> >
> >                    { $$ = makeString($1); }
> >
> >                        | Sconst
> >
> >                    { $$ = makeString($1); }
> >
> >                        | BCONST
> >
> >                    { $$ = makeString($1); }
> >
> >                        | XCONST
> >
> >                    { $$ = makeString($1); }
> >
> >                        | ColId
> >
> >             { $$ = makeString($1); }
> >
> > That is integers, floating point, strings, bitstrings, hexstrings and
> > column references (???).
> >
> > How that exact list came to exist I do not know.
>
> My two thoughts on that:
>
> 1. This list should be improved to allow booleans, and maybe other types
>
> 2. Why then is it like this:
>
> it works:
> CREATE TRIGGER trig_x_10 BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE
> trigger_x('true');
>
> it does not:
> CREATE TRIGGER trig_x_11 BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE
> trigger_x('true'::text);
>
> the error is:
> ERROR:  syntax error at or near "::"
>
> I think there is something wrong.
The grammar doesn't allow any form of expression. It only allows the above
listed types of literals directly.
I am not really sure why it was done that way, but its been that way for a
long time (only insignificant changes since 1997... bitstrings and hex strings
were added after that though).

Why do you wan't to use a boolean directly if you can't use it as the type
itself anyway?

Andres


Re: potential bug in trigger with boolean params

From
Szymon Guz
Date:


On 11 May 2011 12:06, Andres Freund <andres@anarazel.de> wrote:

Why do you wan't to use a boolean directly if you can't use it as the type
itself anyway?


Yep, and this is a really good point :)
I wanted to have consistent api, so use true when I have a boolean value. 
I will use 'true' and add some info on that to the procedure documentation.

regards
Szymon

Re: potential bug in trigger with boolean params

From
Tom Lane
Date:
Andres Freund <andres@anarazel.de> writes:
>> The grammar accepts only a very limited amount of parameters there:
> Err....

> TriggerFuncArg:
>             Iconst
>                 {
>                     char buf[64];
>                     snprintf(buf, sizeof(buf), "%d", $1);
>                     $$ = makeString(pstrdup(buf));
>                 }
>             | FCONST                                { $$ = makeString($1); }
>             | Sconst                                { $$ = makeString($1); }
>             | BCONST                                { $$ = makeString($1); }
>             | XCONST                                { $$ = makeString($1); }
>             | ColId                                 { $$ = makeString($1); }

> That is integers, floating point, strings, bitstrings, hexstrings and column references (???).

> How that exact list came to exist I do not know.

The documentation for CREATE FUNCTION says
   arguments:An optional comma-separated list of arguments to be provided tothe function when the trigger is executed.
Thearguments areliteral string constants. Simple names and numeric constants canbe written here, too, but they will all
beconverted tostrings.
 

The ColId case is meant to cover the "simple names" proviso, but of
course it fails to cover reserved words.  We could trivially fix that
by writing ColLabel instead of ColId.  My initial expectation was that
this would bloat the parser, but it seems not to: the backend gram.o
is exactly the same size after making the change, and ecpg's preproc.o
actually gets smaller (more opportunity to share states?).  So I'm
inclined to do it, rather than having to document that "simple names"
excludes reserved words.

A possibly more interesting question is why BCONST and XCONST were added
there.  The documentation certainly does not say or suggest that those
are legal options, and what's more the behavior could be considered
surprising:

regression=# CREATE TRIGGER trig_x_bconst BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(b'1011');
CREATE TRIGGER
regression=# CREATE TRIGGER trig_x_xconst BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x(x'1234abcd');
CREATE TRIGGER
regression=# \d+ x
...
Triggers:   trig_x_bconst BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE trigger_x('b1011')   trig_x_xconst BEFORE
INSERTON x FOR EACH ROW EXECUTE PROCEDURE trigger_x('x1234abcd')
 

I'm inclined to take those out, because (1) I find it shrinks the
generated grammar a tad (these productions *do* add to the size of the
state tables), and (2) if we don't, we ought to document this behavior,
and I don't want to do that either.

I see this as just a change to make in HEAD, it's not appropriate for
a back-patch.

Objections anyone?
        regards, tom lane


Re: potential bug in trigger with boolean params

From
Andres Freund
Date:
On Wednesday, May 11, 2011 07:25:58 PM Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> >> The grammar accepts only a very limited amount of parameters there:
> > Err....
> > 
> > TriggerFuncArg:
> >             Iconst
> >             
> >                 {
> >                 
> >                     char buf[64];
> >                     snprintf(buf, sizeof(buf), "%d", $1);
> >                     $$ = makeString(pstrdup(buf));
> >                 
> >                 }
> >             | 
> >             | FCONST                                { $$ =
> >             | makeString($1); } Sconst                                {
> >             | $$ = makeString($1); } BCONST                             
> >             |   { $$ = makeString($1); } XCONST                         
> >             |       { $$ = makeString($1); } ColId                      
> >             |           { $$ = makeString($1); }
> > 
> > That is integers, floating point, strings, bitstrings, hexstrings and
> > column references (???).
> > 
> > How that exact list came to exist I do not know.
> 
> The documentation for CREATE FUNCTION says
> 
>     arguments:
>     An optional comma-separated list of arguments to be provided to
>     the function when the trigger is executed. The arguments are
>     literal string constants. Simple names and numeric constants can
>     be written here, too, but they will all be converted to
>     strings.
> 
> The ColId case is meant to cover the "simple names" proviso, but of
> course it fails to cover reserved words.  We could trivially fix that
> by writing ColLabel instead of ColId.  My initial expectation was that
> this would bloat the parser, but it seems not to: the backend gram.o
> is exactly the same size after making the change, and ecpg's preproc.o
> actually gets smaller (more opportunity to share states?).  So I'm
> inclined to do it, rather than having to document that "simple names"
> excludes reserved words.
Good.

> A possibly more interesting question is why BCONST and XCONST were added
> there.  The documentation certainly does not say or suggest that those
> are legal options, and what's more the behavior could be considered
> surprising:
It seems to have originally been added there by Peter (as BITCONST) and then 
split by Thomas Lockhart.

See 73874a06 and eb121ba2
> regression=# CREATE TRIGGER trig_x_bconst BEFORE INSERT ON x FOR EACH ROW
> EXECUTE PROCEDURE trigger_x(b'1011'); CREATE TRIGGER
> regression=# CREATE TRIGGER trig_x_xconst BEFORE INSERT ON x FOR EACH ROW
> EXECUTE PROCEDURE trigger_x(x'1234abcd'); CREATE TRIGGER
> regression=# \d+ x
> ...
> Triggers:
>     trig_x_bconst BEFORE INSERT ON x FOR EACH ROW EXECUTE PROCEDURE
> trigger_x('b1011') trig_x_xconst BEFORE INSERT ON x FOR EACH ROW EXECUTE
> PROCEDURE trigger_x('x1234abcd')
Err. Yes, that looks rather strange. And surprising.

> I'm inclined to take those out, because (1) I find it shrinks the
> generated grammar a tad (these productions *do* add to the size of the
> state tables), and (2) if we don't, we ought to document this behavior,
> and I don't want to do that either.
> I see this as just a change to make in HEAD, it's not appropriate for
> a back-patch.
I would say the above behaviour even is a bug. But given that I haven't 
seen/found anybody complaining about it fixing it properly looks pointless.
So yes, HEAD only sounds fine.

> Objections anyone?
Nope.

Is there a special reason for not using the normal function calling 
mechanisms? It looks to me as it was just done to have an easy way to store it 
in pg_trigger.tgargs.

Andres


Re: potential bug in trigger with boolean params

From
Tom Lane
Date:
Andres Freund <andres@anarazel.de> writes:
> Is there a special reason for not using the normal function calling 
> mechanisms? It looks to me as it was just done to have an easy way to store it 
> in pg_trigger.tgargs.

Well, this is all very historical, dating from Berkeley days AFAIK.
If we had it to do over, I bet we'd do it differently --- but the pain
of changing it seems to exceed any likely benefit.
        regards, tom lane