can't configure PGSync on PG16 standby node

[xmiao-cn]

PGSync version: 3.1.0

Postgres version: PG 16.2

Elasticsearch/OpenSearch version: ES7

Redis version:

Python version:

Problem Description: We want to configure PGSync from PG16.2's standby node to sync data to ES, but the setup steps involve like ' select pg_current_xact(); select * from txid_current();' , maybe there are other statements , which can't be executed on the standby node. What should I do in this case? I can't configure PGSync on PG's primary node to avoid impacting the application running, only can do this sync on standby node. Thanks a lot .

Error Message (if any):

cannot execute pg_current_xct_id() during recovery....... "SELECT * from TXID_CURRENT();"