duckdb_mooncake is a DuckDB extension to read Iceberg tables written by moonlink in real time.

duckdb_mooncake can be installed using the INSTALL command:

INSTALL duckdb_mooncake FROM community;

Mooncake databases can be attached using the ATTACH command, after which tables can be queried using standard SQL.

The example below attaches to the moonlink database 'postgres', from a moonlink instance listening at '/var/lib/postgresql/data/pg_mooncake/moonlink.sock'. This moonlink instance comes prepopulated with a table named public.c:

D ATTACH DATABASE 'mooncake' (TYPE mooncake, URI '/var/lib/postgresql/data/pg_mooncake/moonlink.sock', DATABASE 'postgres');
D SELECT * FROM mooncake.public.c;
┌───────┬─────────┐
│  id   │   val   │
│ int32 │ varchar │
├───────┼─────────┤
│     1 │ Hello   │
│     2 │ World   │
└───────┴─────────┘

To build, type:

git submodule update --init --recursive
GEN=ninja make

To run, run the bundled duckdb shell:

./build/release/duckdb