Today I reinstall a pg extension,then restart the primary and slave. the primary is OK and I can login,and the pg_stat_replication view show the slave is connected.
but when I try to login the slave,it shows:
FATAL:the database system is starting up
I wait several minutes,but it still show the same error. and the primary is no activities,the xlog dir in slave have only 2 WAL files,WAL receiver is there and seams do nothing.I try to restart the slave several times,but nothing help.I even try to use pg_xlogdump to analyze the 2 WAL files,but find nothing abnormal.
But,when I login to the primary,run:
create table xx as select * from big_table.
It produce many WAL，and then the slave became normal and I can login.
it is instresting.I always think that when the pg_stat_replication show the slave there,it means the slave is OK and can be send read stmt.We have some monitor use this and some udf get the alived slave for client read.Now I find I'm wrong.
Any comment？