Postgresql out of memory using timescaledb

Steps to reproduce:

1. Install PgSQL 11 + timescaledb
2. Configure with 9 proxies, with vps ~ 2200
3. Restart zabbix-server process

Result:
On restart, the zabbix server sends a large UPDATE query that eventually exhausts available memory on the pgsql Server. Server is configured with 64Gb RAM, 40Gb Swap, with large work_mem to satisfy requirements of zabbix select queries.

When this occurs, the history syncer processes do not update history and the database/server falls behind, generating multiple triggers and alerts.

See log file...
See memory dump...
Expected:
History syncer does not generate queries that exhaust database memory.

Note: this appears to be the same issue reported in ZBX-9722 .