Thread: Dtrace probes documentation

The dtrace probes documentation [1] spells each probe name with dashes
("transaction-start", "transaction-commit", etc.). Yet as far as I can see,
dtrace only works if you spell the probe names with double underscores
("transaction__start", "transaction__commit", etc.). Why the discrepancy?
Obvious patch attached, in case this needs to be changed.

- Josh / eggyknap

1: http://www.postgresql.org/docs/8.4/static/dynamic-trace.html

Joshua Tolley <eggyknap@gmail.com> writes:
> The dtrace probes documentation [1] spells each probe name with dashes
> ("transaction-start", "transaction-commit", etc.). Yet as far as I can see,
> dtrace only works if you spell the probe names with double underscores
> ("transaction__start", "transaction__commit", etc.). Why the discrepancy?

Read 26.4.3 and .4.  I don't know why they have this bizarre set of
conventions, but the single-hyphen version is the spelling
most visible to end users.
        regards, tom lane

On Thu, May 28, 2009 at 06:28:14PM -0400, Tom Lane wrote:
> Joshua Tolley <eggyknap@gmail.com> writes:
> > The dtrace probes documentation [1] spells each probe name with dashes
> > ("transaction-start", "transaction-commit", etc.). Yet as far as I can see,
> > dtrace only works if you spell the probe names with double underscores
> > ("transaction__start", "transaction__commit", etc.). Why the discrepancy?
>
> Read 26.4.3 and .4.  I don't know why they have this bizarre set of
> conventions, but the single-hyphen version is the spelling
> most visible to end users.

I thought it might be something like that. I've been playing with SystemTap,
and found that only the double-underscore version works for ... well, anything.
See http://blog.endpoint.com/2009/05/postgresql-with-systemtap.html for
details. Perhaps it's worth noting in the documentation that SystemTap users
will need to use the double-underscore version?

- Josh / eggyknap

Joshua Tolley <eggyknap@gmail.com> writes:
> On Thu, May 28, 2009 at 06:28:14PM -0400, Tom Lane wrote:
>> Read 26.4.3 and .4.  I don't know why they have this bizarre set of
>> conventions, but the single-hyphen version is the spelling
>> most visible to end users.

> I thought it might be something like that. I've been playing with SystemTap,
> and found that only the double-underscore version works for ... well, anything.
> See http://blog.endpoint.com/2009/05/postgresql-with-systemtap.html for
> details. Perhaps it's worth noting in the documentation that SystemTap users
> will need to use the double-underscore version?

I think a better solution is to persuade the Systemtap guys that they
ought to accept the single-hyphen spelling.  I've put in a request for
that, we'll see what they think ...
        regards, tom lane

Tom Lane <tgl@sss.pgh.pa.us> writes:

> [...]
>> See http://blog.endpoint.com/2009/05/postgresql-with-systemtap.html for
>> details. Perhaps it's worth noting in the documentation that SystemTap users
>> will need to use the double-underscore version?
>
> I think a better solution is to persuade the Systemtap guys that they
> ought to accept the single-hyphen spelling.  [...]

Will do: http://sourceware.org/PR10225.

- FChE