allow to use application name for upgrade #915
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Hello @hughcapet, is there any chances to review it? Thanks! |
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Hello @jopadi @idanovinda @hughcapet @Jan-M @sdudoladov, Can you tell me what you think of this PR? it would help a lot when postgres is used on top of service mesh such as istio thanks! |
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why not query both fields, and then try depending on env var to use the application name or fall back to ip. i am not such a big fan of templating those parts of sql queries. |
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But yes, we will keep an eye on this, if this helps in service mesh world we should help you. |
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Hello @Jan-M, first thanks for quick reply!
I'm not (at all) an expert of SQL (and SQL in python) ^_^ so I did the best I could :) I'm not sure on how to retrieve the values after the requests: I should propose something like this and it would work?: streaming = {a: l for a, l in self.postgresql.query(
("SELECT client_addr, application_name, pg_catalog.pg_{0}_{1}_diff(pg_catalog.pg_current_{0}_{1}(),"
" COALESCE(replay_{1}, '0/0'))::bigint FROM pg_catalog.pg_stat_replication")
.format(self.postgresql.wal_name, self.postgresql.lsn_name))}
def ensure_replica_state(member):
ip = member.conn_kwargs().get('host')
lag = streaming.get(ip)
if os.getenv('USE_APPLICATION_NAME_IN_UPGRADE'):
lag = streaming.get(member.name)
if lag is None:
return logger.error('Member %s is not streaming from the primary', member.name) |
Instead of using replica IP address, allow to use replica name in case IP address is not reliable (like when using a service mesh). This trigger is controller by using an environment variable and default behavior is the previous one Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>
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hi @Jan-M, I tried to apply your comment on the PR :) |
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Another issue we are seeing with istio is that when the COPY TO PROGRAM is executed for rsync it is sending the the istio 127.0.0.6 ip for PRIMARY_IP |
| @@ -172,13 +172,15 @@ def ensure_replicas_state(self, cluster): | |||
| """ | |||
| self.replica_connections = {} | |||
| streaming = {a: l for a, l in self.postgresql.query( | |||
| ("SELECT client_addr, pg_catalog.pg_{0}_{1}_diff(pg_catalog.pg_current_{0}_{1}()," | |||
| ("SELECT client_addr, application_name, pg_catalog.pg_{0}_{1}_diff(pg_catalog.pg_current_{0}_{1}()," | |||
There was a problem hiding this comment.
This does not work. The result it put in a dictionary, so it expects to unpack two elements, not three. You need to select either client_addr or application_name.
| @@ -172,13 +172,15 @@ def ensure_replicas_state(self, cluster): | |||
| """ | |||
| self.replica_connections = {} | |||
| streaming = {a: l for a, l in self.postgresql.query( | |||
| ("SELECT client_addr, pg_catalog.pg_{0}_{1}_diff(pg_catalog.pg_current_{0}_{1}()," | |||
| ("SELECT client_addr, application_name, pg_catalog.pg_{0}_{1}_diff(pg_catalog.pg_current_{0}_{1}()," | |||
| " COALESCE(replay_{1}, '0/0'))::bigint FROM pg_catalog.pg_stat_replication") | |||
| .format(self.postgresql.wal_name, self.postgresql.lsn_name))} | |||
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| def ensure_replica_state(member): | |||
| ip = member.conn_kwargs().get('host') | |||
| lag = streaming.get(ip) | |||
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This should be in the else of the next if.
Instead of using replica IP address, allow to use replica name in case IP address is not reliable (like when using a service mesh).
This trigger is controller by using an environment variable (
USE_APPLICATION_NAME_IN_UPGRADE) and default behavior is the previous one.closes zalando/postgres-operator#1629