Re: PATCH: psql tab completion for SELECT

On January 14, 2018 5:44:01 PM PST, Edmund Horner <ejrh00(at)gmail(dot)com> wrote:
>On 15 January 2018 at 14:20, Andres Freund <andres(at)anarazel(dot)de> wrote:
>> On January 14, 2018 5:12:37 PM PST, Edmund Horner <ejrh00(at)gmail(dot)com>
>wrote:
>>>And here's a patch to add savepoint protection for tab completion.
>>
>> It'd be good to explain what that means, so people don't have to read
>the patch to be able to discuss whether this is a good idea.
>
>
>Good idea.
>
>In psql if you have readline support and press TAB, psql will often
>run a DB query to get a list of possible completions to type on your
>current command line.
>
>It uses the current DB connection for this, which means that if the
>tab completion query fails (e.g. because psql is querying catalog
>objects that doesn't exist in your server), the current transaction
>(if any) fails. An example of this happening is:

Ah, that's what I thought. I don't think this is the right fix.

> pg_subscription table doesn't
>exist on 9.2! User realises their mistake and types a different
>command)
>
> postgres=# select * from foo;
> ERROR: current transaction is aborted, commands ignored until end
>of transaction block

All worries like this are supposed to check the server version.

Andres
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