Обсуждение: BUG #13994: Documentation of pg_notify is incorrect.
The following bug has been logged on the website: Bug reference: 13994 Logged by: Peter McGeeney Email address: junkmesend@gmail.com PostgreSQL version: 9.5.1 Operating system: Windows 8.1 Description: The documentation at http://www.postgresql.org/docs/9.5/static/sql-notify.html Recommends the command... SELECT pg_notify('fo' || 'o', 'pay' || 'load'); which doesn't work but PERFORM pg_notify('fo' || 'o', 'pay' || 'load'); does work, as explained here. http://stackoverflow.com/questions/5412474/using-pg-notify-in-postgresql-trigger-function?lq=1 Please note that this is nothing to do with the uppercase issue with pg_notify here... http://www.postgresql.org/message-id/201103031520.p23FKxFJ049037@wwwmaster.postgresql.org Many thanks Pete
On Sun, 28 Feb 2016 23:20:40 +0000 junkmesend@gmail.com wrote: > The following bug has been logged on the website: > > Bug reference: 13994 > Logged by: Peter McGeeney > Email address: junkmesend@gmail.com > PostgreSQL version: 9.5.1 > Operating system: Windows 8.1 > Description: > > The documentation at > > http://www.postgresql.org/docs/9.5/static/sql-notify.html > > Recommends the command... > > SELECT pg_notify('fo' || 'o', 'pay' || 'load'); > > which doesn't work but > > PERFORM pg_notify('fo' || 'o', 'pay' || 'load'); > > does work, as explained here. > > http://stackoverflow.com/questions/5412474/using-pg-notify-in-postgresql-trigger-function?lq=1 This is working as documented. The trigger function is using language plpgsql, but the psql session is sql. SELECT works differently in plpgsql than in sql. Specifically it requires a destination for the result. Otherwise use PERFORM. See the fine manual: http://www.postgresql.org/docs/9.5/static/plpgsql-statements.html#PLPGSQL-STATEMENTS-SQL-NORESULT -dg -- David Gould 510 282 0869 daveg@sonic.net If simplicity worked, the world would be overrun with insects.
On 02/28/2016 03:20 PM, junkmesend@gmail.com wrote: > http://www.postgresql.org/docs/9.5/static/sql-notify.html >=20 > Recommends the command... >=20 > SELECT pg_notify('fo' || 'o', 'pay' || 'load'); Which works fine: postgres=3D# SELECT pg_notify('fo' || 'o', 'pay' || 'load'); pg_notify ----------- (1 row) > PERFORM pg_notify('fo' || 'o', 'pay' || 'load'); >=20 > does work, as explained here. >=20 > http://stackoverflow.com/questions/5412474/using-pg-notify-in-postgresql-= trigger-function?lq=3D1 You are confusing SQL statement syntax with PL/pgSQL function syntax. See: http://www.postgresql.org/docs/9.5/static/plpgsql-statements.html#PLPGSQL-S= TATEMENTS-SQL-NORESULT Joe --=20 Crunchy Data - http://crunchydata.com PostgreSQL Support for Secure Enterprises Consulting, Training, & Open Source Development