Re: libpq options
| От | Magnus Hagander |
|---|---|
| Тема | Re: libpq options |
| Дата | |
| Msg-id | CABUevEzwbfDb5fUWc7opVFyGBeCXqChrq-S1KXRSYDDexSuthw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: libpq options (Michael Paquier <michael@paquier.xyz>) |
| Ответы |
Re: libpq options
|
| Список | pgsql-docs |
On Fri, Mar 2, 2018 at 2:50 AM, Michael Paquier <michael@paquier.xyz> wrote:
On Thu, Mar 01, 2018 at 01:35:54AM -0800, Andres Freund wrote:
> On 2017-11-25 19:05:54 +0900, Michael Paquier wrote:
>> A Boolean value of <literal>true</literal> tells the backend
>> + to go into walsender mode, wherein a small set of replication commands
>> + can be issued instead of SQL statements.
>
> This actually is wrong now I think. Petr?
On more or less HEAD:
$ psql -X -d "replication=1 dbname=postgres"
postgres=# create table aa (a int);
ERROR: cannot execute SQL commands in WAL sender for physical replication
$ psql -X -d "replication=database dbname=postgres"
postgres=# create table aa (a int);
CREATE TABLE
So one needs to use replication=database in order to be able to issue
normal SQL statements, while replication=true enforces physical
replication where this cannot happen (no connection to a specified
database).
To nitpick:
+ protocol. A Boolean value of <literal>true</literal> tells the backend
We don't really have boolean values here, do we? It's just the string true that's treated as a boolean by the backend. It just sounds really weird to me when written that way. Particularly since the next sentence talks about passing "database" as the same thing.
I know that's pretty much nitpicking, but I want to make sure I haven't actually missed/forgotten how some part of that one is handled..
It also talks separately about "going into walsender mode" (=physical replication) and "instructs the walsender to connect to the database". I think that's a bit confusing. I suggest just calling it "physical replication mode" and "logical replication mode", and not bother mentioning walsender since that's quite internal.
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