setop
/
sqlite-parquet-vtable
mirror of https://github.com/cldellow/sqlite-parquet-vtable.git
1
0
Fork 0
Code Releases Activity
sqlite-parquet-vtable/README.md

1.4 KiB
Raw Blame History

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
  2. Run ./build-sqlite to fetch and build the SQLite dev bits
  3. Run ./parquet/make to build the module
  4. 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('demo.parquet');
sqlite> select * from demo limit 1;
...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

These are not supported:

  • UINT8/UINT16/UINT32/UINT64
  • Fixed length byte arrays, including JSON and BSON subtypes
  • DECIMAL