At this time, the read block size for HVR/LDP for Oracle on ASM is limited to 64KB by default. Following parameter can be used to increase the read block size to 4MB. However, this parameter doesn't work for Oracle Pluggable database. We need this parameter to work for Oracle pluggable database. 

ENABLE_GOLDENGATE_REPLICATION=1

Please make Kate Holland (kate.holland@fivetran.com) aware of this enhancement request since she will be helping to escalate this.