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From: Wetmore, Matthew  (CTR) <[email protected]>
To: Steve Midgley <[email protected]>
To: intmail01 <[email protected]>
Cc: [email protected] <[email protected]>
Subject: How to know if all insertions are finished
Date: Fri, 8 Mar 2024 16:52:18 +0000
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAJexoSJcq8taBbyFvCKnZF=A0DLK+-SdVdeVaGasopUCHukjdg@mail.gmail.com>
References: <CAKJANSD8QG2XbkexZFpd=afVyvFfG=xNm6zVF-Z1DcK0+QrCig@mail.gmail.com>
	<CAJexoSJcq8taBbyFvCKnZF=A0DLK+-SdVdeVaGasopUCHukjdg@mail.gmail.com>

Begin work
Select count(*) prior to insert.
Insert  from file
Select count post insert
If new count  matches old count + new rows from insert file
Commit/rollback

From: Steve Midgley <[email protected]>
Sent: Friday, March 8, 2024 8:26 AM
To: intmail01 <[email protected]>
Cc: [email protected]
Subject: [EXTERNAL] Re: How to know if all insertions are finished



On Fri, Mar 8, 2024 at 4:01 AM intmail01 <[email protected]<mailto:[email protected]>> wrote:
Hi,

Is there any way to know if several insertion are terminated.
I use libreoffice base to import at the same time many lines. When all lines are inserted I have to do some data check. I dont find any way to know if the insertion ends to start some function automatically.
I tried to use a STATEMENT trigger type but all lines are treated as statement.

I think you are saying in your last line that each insert line is treated as an individual statement, so you get a bunch of trigger notifications instead of just one, and you don't know how to detect when you have received the final insert?

The first thing I'd look for is whether I could wrap all the libreoffice inserts into a single transaction block, and then event off of the transaction block completing.

Barring that, and noting I'm not familiar with how libreoffice would send the inserts, one option could be to put a listen/notify pattern at the end of your insert code, if it's possible to add a line of sql at the end of the inserts? Of course, if you can do that, you might also be able to wrap the whole thing with a transaction, but listen/notify might be simpler to event off of..

-- In session/connection 1
BEGIN;
-- Perform your bulk insert operation here
COMMIT;
NOTIFY inserts_done;

-- In session/connection 2
LISTEN inserts_done;
-- Once notification is received, proceed with necessary operations

If you can't do something like this, the only other (relatively horrible) things I can think of would be to:

  1.  Put a dummy row at the end of your insert data (if you can guarantee it would be inserted last during the bulk operation), and then build a trigger/condition to detect insertion of a row matching the dummy data that deletes the dummy row and then proceeds to kick off whatever other processes you want, or:
  2.  Use a time based model, where you build an understanding of how long your inserts take to execute, and build a monitor that kicks off on each insert, and if another insert is not detected within a certain amount of wait time, you conclude that there are no more inserts coming, and you then kick off whatever other processes you want..
Hopefully someone with deeper Postgres knowledge has other, more reliable solutions that leverage Postgres, but if your inserts are all discrete, and you don't have control over the sql itself.

Steve


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