Percona XtraDB Cluster 5.7.17-27.20 基于以下这些项目：
Percona Server 5.6.42
Codership WSREP API release 5.6.42
Codership Galera library 3.25
PXC-2281: Debug symbols were missing in Debian dbg packages.
PXC-2220: Starting two instances of Percona XtraDB Cluster on the same node could cause writing transactions to a page store instead of a galera.cache ring buffer, resulting in huge memory consumption because of retaining already applied write-sets.
rgcs.fc_limit=0not allowed as dynamic setting to avoid generating flow control on every message was still possible in
my.cnfdue to the inconsistent check.
read_only=1caused race condition.