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Date:   Sun, 1 Aug 2021 15:39:25 +0200
From:   "Ahmed S. Darwish" <a.darwish@linutronix.de>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Tom Zanussi <zanussi@kernel.org>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-rt-users <linux-rt-users@vger.kernel.org>,
        Clark Williams <williams@redhat.com>
Subject: Re: [PATCH 17/17] libtracefs: Add man page for tracefs_sql()
Message-ID: <YQakDYRnId+bK+ue@lx-t490>
References: <20210730221824.595597-1-rostedt@goodmis.org>
 <20210730221824.595597-18-rostedt@goodmis.org>
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On Fri, Jul 30, 2021, Steven Rostedt wrote:
> +
> +The SQL format is as follows:
> +
> +*SELECT* <fields> FROM <start-event> JOIN <end-event> ON <matching-fields> WHERE <filter>
> +
> +Note, although the examples show the SQL commands in uppercase, they are not required to
> +be so. That is, you can use "SELECT" or "select" or "sElEct".
> +

Maybe it would be helpful to mention that, unlike normal SELECT queries,
the JOIN and ON parts above are _not_ optional?

That is, generic "one event source" queries:

  SELECT common_pid,msr,val FROM write_msr WHERE msr=72

are not supported. (I wish they were though ;-))

BTW, thanks a lot for this work. It will finally make synthetic events
usable!

Kind regards,

--
Ahmed S. Darwish
Linutronix GmbH