Re: [HACKERS] "SQL sentence"?

2017-02-18 Thread Jim Nasby

On 2/17/17 10:46 PM, Alvaro Herrera wrote:

Sure.  We have the extension that turned the command into JSON.  It's
still an unfinished patch, sadly, even though Alex Shulgin spent a lot
of effort trying to get it finished.  It is still missing a nontrivial
amount of work, but within reach ISTM.


You're speaking of 
https://www.postgresql.org/message-id/CACACo5Q_UXYwF117LBhjZ3xaMPyrgqnqE%3DmXvRhEfjJ51aCfwQ%40mail.gmail.com 
? Can you reply to that to restart discussion?

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Re: [HACKERS] "SQL sentence"?

2017-02-17 Thread Jim Nasby

On 2/17/17 10:46 PM, Alvaro Herrera wrote:

Jim Nasby wrote:

On 2/17/17 10:19 PM, Alvaro Herrera wrote:

(FWIW, I'm wondering because I was just looking to see why there's no
details for things like altering a column in a table.)

Do you mean you want to have access to the details of the alter table
operations being executed?  There's no structured data for that; you
need to write a C function to examine the pg_ddl_command opaque column.

Yeah. It doesn't seem unreasonable for a user to want to get at that info.

Sure.  We have the extension that turned the command into JSON.  It's
still an unfinished patch, sadly, even though Alex Shulgin spent a lot
of effort trying to get it finished.  It is still missing a nontrivial
amount of work, but within reach ISTM.


I wonder if there's some generic way we could make C structs to JSON. 
IIRC there's other places where that ability would be handly.

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Re: [HACKERS] "SQL sentence"?

2017-02-17 Thread Alvaro Herrera
Jim Nasby wrote:
> On 2/17/17 10:19 PM, Alvaro Herrera wrote:
> > > (FWIW, I'm wondering because I was just looking to see why there's no
> > > details for things like altering a column in a table.)
> > Do you mean you want to have access to the details of the alter table
> > operations being executed?  There's no structured data for that; you
> > need to write a C function to examine the pg_ddl_command opaque column.
> 
> Yeah. It doesn't seem unreasonable for a user to want to get at that info.

Sure.  We have the extension that turned the command into JSON.  It's
still an unfinished patch, sadly, even though Alex Shulgin spent a lot
of effort trying to get it finished.  It is still missing a nontrivial
amount of work, but within reach ISTM.

> Could the opaque column be mapped to a composite?

No.  If it could, we would just have added the fields to the output of
the function.

> I guess that'd be a bit of
> a pain due to the union. :/ And I have a suspicion that alterTable.subcmds
> is a list of CollectedCommand, making things more fun.

The AT subcmds have their own struct, so it's even more fun than that.

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Re: [HACKERS] "SQL sentence"?

2017-02-17 Thread Jim Nasby

On 2/17/17 10:19 PM, Alvaro Herrera wrote:

(FWIW, I'm wondering because I was just looking to see why there's no
details for things like altering a column in a table.)

Do you mean you want to have access to the details of the alter table
operations being executed?  There's no structured data for that; you
need to write a C function to examine the pg_ddl_command opaque column.


Yeah. It doesn't seem unreasonable for a user to want to get at that info.

Could the opaque column be mapped to a composite? I guess that'd be a 
bit of a pain due to the union. :/ And I have a suspicion that 
alterTable.subcmds is a list of CollectedCommand, making things more fun.

--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532)


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Re: [HACKERS] "SQL sentence"?

2017-02-17 Thread Alvaro Herrera
Jim Nasby wrote:
> I'm confused by this:
> 
> "pg_event_trigger_ddl_commands returns one row for each base command
> executed; some commands that are a single SQL sentence may return more than
> one row."
> 
> What is a "SQL sentence"?

I meant "a single SQL command".  The word "sentence" probably just
slipped through.  Will fix.

> (FWIW, I'm wondering because I was just looking to see why there's no
> details for things like altering a column in a table.)

Do you mean you want to have access to the details of the alter table
operations being executed?  There's no structured data for that; you
need to write a C function to examine the pg_ddl_command opaque column.

-- 
Álvaro Herrerahttps://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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[HACKERS] "SQL sentence"?

2017-02-17 Thread Jim Nasby

I'm confused by this:

"pg_event_trigger_ddl_commands returns one row for each base command 
executed; some commands that are a single SQL sentence may return more 
than one row."


What is a "SQL sentence"?

(FWIW, I'm wondering because I was just looking to see why there's no 
details for things like altering a column in a table.)

--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532)


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