docs: add pushdown support docs

docs/airtable.md

@@ -87,6 +87,10 @@ The full list of foreign table options are below:
 - `table_id` - Airtable table ID, required.
 - `view_id` - Airtable view ID, optional.
 
+## Query Pushdown Support
+
+This FDW doesn't support query pushdown.
+
 ## Examples
 
 Some examples on how to use Airtable foreign tables.

docs/bigquery.md

@@ -129,6 +129,10 @@ The full list of foreign table options are below:
 - `timeout` - Query request timeout in milliseconds, optional. Default is '30000' (30 seconds).
 - `rowid_column` - Primary key column name, optional for data scan, required for data modify
 
+## Query Pushdown Support
+
+This FDW supports `where`, `order by` and `limit` clause pushdown.
+
 ## Inserting Rows & the Streaming Buffer
 
 This foreign data wrapper uses BigQuery’s `insertAll` API method to create a `streamingBuffer` with an associated partition time. **Within that partition time, the data cannot be updated, deleted, or fully exported**. Only after the time has elapsed (up to 90 minutes according to [BigQuery’s documentation](https://cloud.google.com/bigquery/docs/streaming-data-into-bigquery)); can you perform operations.

docs/clickhouse.md

@@ -133,6 +133,10 @@ The full list of foreign table options are below:
 
 - `rowid_column` - Primary key column name, optional for data scan, required for data modify
 
+## Query Pushdown Support
+
+This FDW supports `where`, `order by` and `limit` clause pushdown, as well as parametrized view (see above).
+
 ## Examples
 
 Some examples on how to use ClickHouse foreign tables.

docs/firebase.md

@@ -106,6 +106,10 @@ The full list of foreign table options are below:
   - `firestore/my-collection`
   - `firestore/my-collection/my-document/another-collection`
 
+## Query Pushdown Support
+
+This FDW doesn't support query pushdown.
+
 ## Examples
 
 Some examples on how to use Firebase foreign tables.

docs/logflare.md

@@ -92,6 +92,10 @@ The full list of foreign table options are below:
 
 - `endpoint` - Logflare endpoint UUID or name, required.
 
+## Query Pushdown Support
+
+This FDW doesn't support query pushdown.
+
 ## Examples
 
 Some examples on how to use Logflare foreign tables.

docs/s3.md

@@ -140,6 +140,10 @@ The full list of foreign table options are below:
 - `has_header` - If the CSV file has header, optional. `true` or `false`, default is `false`
 - `compress` - Compression algorithm, optional. One of `gzip`, `bzip2`, `xz`, `zlib`, default is no compression
 
+## Query Pushdown Support
+
+This FDW doesn't support query pushdown.
+
 ## Examples
 
 Some examples on how to use S3 foreign tables.

docs/stripe.md

@@ -766,6 +766,20 @@ While any column is allowed in a where clause, it is most efficient to filter by
 - id
 - destination
 
+## Query Pushdown Support
+
+This FDW supports `where` clause pushdown. You can specify a filter in `where` clause and it will be passed to Stripe API call.
+
+For example, this query
+
+```sql
+select * from stripe.customers where id = 'cus_xxx';
+```
+
+will be translated Stripe API call: `https://api.stripe.com/v1/customers/cus_xxx`.
+
+For supported filter columns for each object, please check out foreign table documents above.
+
 ## Examples
 
 Some examples on how to use Stripe foreign tables.