I decommissioned 3 nodes this way…
cockroach node decommission 10 --certs-dir=certs --host=
I watched them drain, etc. and they now show decommissioned. All looked ok until I tried to run my java benchmark program. and it started throwing tons of these exceptions…
org.postgresql.util.PSQLException: ERROR: result is ambiguous (error=unable to dial n11: breaker open [exhausted])
The nodes in the exceptions are the three decommisioned nodes. The cockroach log on the remaining 9 nodes are also showing repeated messages trying to reach the decommisioned nodes, but the main problem is the SQL exceptions with the strange mention of these nodes.
I was perhaps too ambitious, this is 19.2 beta.