Thread: psql question: aborting a "script"

On 03/15/2016 07:33 AM, John McKown wrote:

I'm likely abusing the psql program. What I have is an awk program which
reads a file and produces a number of INSERT INTO commands. I then feed
these commands into psql to execute them. Yes, a Perl program would be a
better idea. Anyway, sometimes the commands are rejected due to some
problem, such as duplicate primary key. What I wish is that the psql
command had a switch, or control command, which would say "exit from
psql if anything fails". To me, this is like the BASH "set -e" command
for a shell script. Does this sound like a useful addition. Or am I just
missing where it already exists?

Would this help?:

http://www.postgresql.org/docs/9.5/interactive/app-psql.html
"-1
--single-transaction

    When psql executes a script, adding this option wraps BEGIN/COMMIT around the script to execute it as a single transaction. This ensures that either all the commands complete successfully, or no changes are applied.

    If the script itself uses BEGIN, COMMIT, or ROLLBACK, this option will not have the desired effects. Also, if the script contains any command that cannot be executed inside a transaction block, specifying this option will cause that command (and hence the whole transaction) to fail.

"

--
Adrian Klaver
adrian.klaver@aklaver.com

On Tue, Mar 15, 2016 at 9:38 AM, Adrian Klaver <adrian.klaver@aklaver.com> wrote:

On 03/15/2016 07:33 AM, John McKown wrote:

I'm likely abusing the psql program. What I have is an awk program which
reads a file and produces a number of INSERT INTO commands. I then feed
these commands into psql to execute them. Yes, a Perl program would be a
better idea. Anyway, sometimes the commands are rejected due to some
problem, such as duplicate primary key. What I wish is that the psql
command had a switch, or control command, which would say "exit from
psql if anything fails". To me, this is like the BASH "set -e" command
for a shell script. Does this sound like a useful addition. Or am I just
missing where it already exists?

Would this help?:

​Well, actually, no. It does force a ROLLBACK, but the individual INSERT INTO commands are still being read and rejected, one by one. And there are literally _thousands_ of them. It is not a "problem", per se. It's just that it is "wasting" time and effort on the part of the system. 

If you're wonder why I do it this way, it is because the commands that I generate are simple SQL standard commands. And they can be fed into programs which update different SQL data bases, such as Postgresql (psql command), MariaDB (mysql command), SQLite3 (sqlite3 command), and so forth. Basically, I'm lazy and don't want to code multiple RDMS-oriented commands, or have a single command which can interface with multiple RDMS systems. ​

 

http://www.postgresql.org/docs/9.5/interactive/app-psql.html
"-1
--single-transaction

    When psql executes a script, adding this option wraps BEGIN/COMMIT around the script to execute it as a single transaction. This ensures that either all the commands complete successfully, or no changes are applied.

    If the script itself uses BEGIN, COMMIT, or ROLLBACK, this option will not have the desired effects. Also, if the script contains any command that cannot be executed inside a transaction block, specifying this option will cause that command (and hence the whole transaction) to fail.

"

--
Adrian Klaver
adrian.klaver@aklaver.com

--

A fail-safe circuit will destroy others. -- Klipstein

Maranatha! <><
John McKown

On Tue, Mar 15, 2016 at 10:49 AM, John McKown <john.archie.mckown@gmail.com> wrote:

On Tue, Mar 15, 2016 at 9:38 AM, Adrian Klaver <adrian.klaver@aklaver.com> wrote:

On 03/15/2016 07:33 AM, John McKown wrote:

I'm likely abusing the psql program. What I have is an awk program which
reads a file and produces a number of INSERT INTO commands. I then feed
these commands into psql to execute them. Yes, a Perl program would be a
better idea. Anyway, sometimes the commands are rejected due to some
problem, such as duplicate primary key. What I wish is that the psql
command had a switch, or control command, which would say "exit from
psql if anything fails". To me, this is like the BASH "set -e" command
for a shell script. Does this sound like a useful addition. Or am I just
missing where it already exists?

Would this help?:

​Well, actually, no. It does force a ROLLBACK, but the individual INSERT INTO commands are still being read and rejected, one by one. And there are literally _thousands_ of them. It is not a "problem", per se. It's just that it is "wasting" time and effort on the part of the system. 

If you're wonder why I do it this way, it is because the commands that I generate are simple SQL standard commands. And they can be fed into programs which update different SQL data bases, such as Postgresql (psql command), MariaDB (mysql command), SQLite3 (sqlite3 command), and so forth. Basically, I'm lazy and don't want to code multiple RDMS-oriented commands, or have a single command which can interface with multiple RDMS systems. ​

 

http://www.postgresql.org/docs/9.5/interactive/app-psql.html
"-1
--single-transaction

    When psql executes a script, adding this option wraps BEGIN/COMMIT around the script to execute it as a single transaction. This ensures that either all the commands complete successfully, or no changes are applied.

    If the script itself uses BEGIN, COMMIT, or ROLLBACK, this option will not have the desired effects. Also, if the script contains any command that cannot be executed inside a transaction block, specifying this option will cause that command (and hence the whole transaction) to fail.

"

--
Adrian Klaver
adrian.klaver@aklaver.com

--

A fail-safe circuit will destroy others. -- Klipstein

Maranatha! <><
John McKown

What you really want is

"

ON_ERROR_STOP

By default, command processing continues after an error. When this variable is set to on, processing will instead stop immediately. In interactive mode, psql will return to the command prompt; otherwise, psql will exit, returning error code 3 to distinguish this case from fatal error conditions, which are reported using error code 1. In either case, any currently running scripts (the top-level script, if any, and any other scripts which it may have in invoked) will be terminated immediately. If the top-level command string contained multiple SQL commands, processing will stop with the current command.

"

So just
SET ON_ERROR_STOP = ON

before any other statements

--

Melvin Davidson
I reserve the right to fantasize.  Whether or not you
wish to share my fantasy is entirely up to you.