sqlite-parquet-vtable

A SQLite virtual table extension to expose Parquet files as SQL tables.

Caveats

I'm not an experienced C/C++ programmer. This library is definitely not bombproof. It's good enough for my use case, and may be good enough for yours, too.

• I don't use sqlite3_malloc and sqlite3_free for C++ objects
  • Maybe this doesn't matter, since portability isn't a goal
• The C -> C++ interop definitely leaks some C++ exceptions
  • Obvious cases like file not found and unsupported Parquet types are OK
  • Low memory conditions aren't handled gracefully.

Building

1. Install parquet-cpp
   1. Master appears to be broken for text row group stats; see https://github.com/cldellow/sqlite-parquet-vtable/issues/5 for which versions to use
2. Run ./build-sqlite to fetch and build the SQLite dev bits
3. Run ./parquet/make to build the module
   1. You will need to fixup the paths in this file to point at your local parquet-cpp folder.

Use

$ sqlite/sqlite3
sqlite> .load parquet/libparquet
sqlite> CREATE VIRTUAL TABLE demo USING parquet('parquet-generator/100-rows-1.parquet');
sqlite> SELECT * FROM demo;
...if all goes well, you'll see data here!...

Supported features

Index

Only full table scans are supported.

Types

These types are supported:

• INT96 timestamps (exposed as milliseconds since the epoch)
• INT8/INT16/INT32/INT64
• UTF8 strings
• BOOLEAN
• FLOAT
• DOUBLE
• Variable- and fixed-length byte arrays

These are not supported:

• UINT8/UINT16/UINT32/UINT64
• DECIMAL