Don't pay heed to wal_sender_timeout while creating a decoding slot.
Don't pay heed to wal_sender_timeout while creating a decoding slot.

Sometimes CREATE_REPLICATION_SLOT ... LOGICAL ... needs to wait for
further WAL using WalSndWaitForWal(). That used to always respect
wal_sender_timeout and kill the session when waiting long enough
because no feedback/ping messages can be sent while the slot is still
being created.
Introduce the notion that last_reply_timestamp = 0 means that the
walsender currently doesn't need timeout processing to avoid that
problem. Use that notion for CREATE_REPLICATION_SLOT ... LOGICAL.

Bugreport and initial patch by Steve Singer, revised by me.

greenplum-db/gpdb,adam8157/gpdb,pavanvd/postgres-xl,jmcatamney/gpdb,pavanvd/postgres-xl,jmcatamney/gpdb,greenplum-db/gpdb,yazun/postgres-xl,greenplum-db/gpdb,xinzweb/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,xinzweb/gpdb,lisakowen/gpdb,oberstet/postgres-xl,ashwinstar/gpdb,Postgres-XL/Postgres-XL,lisakowen/gpdb,ashwinstar/gpdb,zeroae/postgres-xl,jmcatamney/gpdb,lisakowen/gpdb,oberstet/postgres-xl,pavanvd/postgres-xl,ovr/postgres-xl,ovr/postgres-xl,oberstet/postgres-xl,ashwinstar/gpdb,oberstet/postgres-xl,ovr/postgres-xl,Postgres-XL/Postgres-XL,zeroae/postgres-xl,lisakowen/gpdb,yazun/postgres-xl,lisakowen/gpdb,50wu/gpdb,techdragon/Postgres-XL,adam8157/gpdb,50wu/gpdb,50wu/gpdb,lisakowen/gpdb,Postgres-XL/Postgres-XL,zeroae/postgres-xl,xinzweb/gpdb,50wu/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,adam8157/gpdb,50wu/gpdb,adam8157/gpdb,Postgres-XL/Postgres-XL,50wu/gpdb,zeroae/postgres-xl,lisakowen/gpdb,zeroae/postgres-xl,jmcatamney/gpdb,ashwinstar/gpdb,yazun/postgres-xl,pavanvd/postgres-xl,greenplum-db/gpdb,oberstet/postgres-xl,pavanvd/postgres-xl,xinzweb/gpdb,techdragon/Postgres-XL,jmcatamney/gpdb,techdragon/Postgres-XL,xinzweb/gpdb,ovr/postgres-xl,Postgres-XL/Postgres-XL,ashwinstar/gpdb,adam8157/gpdb,xinzweb/gpdb,jmcatamney/gpdb,lisakowen/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,techdragon/Postgres-XL,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,xinzweb/gpdb,ashwinstar/gpdb,ovr/postgres-xl,jmcatamney/gpdb,techdragon/Postgres-XL,50wu/gpdb,yazun/postgres-xl,adam8157/gpdb,yazun/postgres-xl,xinzweb/gpdb,adam8157/gpdb