We have just released version 1.2.0 of the Foreign Data Wrapper for InfluxDB.
This release can work with PostgreSQL 10, 11, 12, 13 and 14.
This release improves following item (from 1.1.1):

• Support schemaless feature

The FDW supports following features :

• InfluxDB FDW supports pushed down some aggregate functions: count, stddev, sum, max, min.
• InfluxDB FDW supports INSERT, DELETE statements.
• InfluxDB FDW supports bulk INSERT by using batch_size option from PostgreSQL version 14 or later.
• WHERE clauses including timestamp, interval and now() functions are pushed down.
• LIMIT...OFFSET clauses are pushed down when there is LIMIT clause only or both LIMIT and OFFSET.
• Support schemaless mode that allows access to elements in the data file without changing the table definition by using jsonb typed column.

Limitations :

• UPDATE is not supported.
• WITH CHECK OPTION constraints is not supported. Following limitations originate from data model and query language of InfluxDB.
• Result sets have different number of rows depending on specified target list. For example, SELECT field1 FROM t1 and SELECT field2 FROM t1 returns different number of rows if the number of points with field1 and field2 are different in InfluxDB database.
• Timestamp precision may be lost because timestamp resolution of PostgreSQL is microseconds while that of InfluxDB is nanoseconds.
• Conditions like WHERE time + interval '1 day' < now() do not work. Please use WHERE time < now() - interval '1 day'.

This is developed by Toshiba Software Engineering & Technology Center. Please see the repository for details. Source repository : https://github.com/pgspider/influxdb_fdw