Contents

• chDB integration
  • Write rows
  • Read rows

chDB integration

Use Native format to stream data between chDB and PostgreSQL. Match writer types to declared ClickHouse table structure, including arrays and other nested types.

Write rows

Open an insert stream with chdb_stream_insert(conn, query, "Native"). Append rows with pgch_append_datum or pgch_append_slot. Use pgch_writer_rows or pgch_writer_bytes to decide when to send a block:

pgch_buf buf = {};

pgch_writer_flush(writer, &buf, NULL);
if (chdb_stream_append(stream, (char *) buf.data, buf.len) != CHDBSuccess)
    ereport(ERROR, ...);
pgch_buf_reset(&buf);

Read rows

Apply PGCH_NATIVE_SETTINGS to queries returning Native data. Wrap chdb_stream_fetch_result in a chunk source, keeping each result buffer alive until next chunk request. Use pgch_reader_init_chunks with NULL options for local framing.

Read rows and convert them to target PostgreSQL types with pgch_reader_fill.

See pg_chdb for query execution, streaming, and PostgreSQL COPY integration.