LEngine

LEngine is under development.

Goal

• Performance

Non-goals

• Fault tolerance
• Database (not even KVDB)

Features

• Atomic updates

Future?

• Garbage collection
• User-defined operations

Wire Format

Log file

The log file is append-only.

+-------+-------+-----+----------+-------+-----+----------+
| Entry | Entry | ... | Sentinel | Entry | ... | Sentinel |
+-------+-------+-----+----------+-------+-----+----------+

• An entry is a region of contiguous bytes. Its size is undetermined.
• A sentinel is a special entry. (Currently, they're just entries.)

All data are stored as-is.

Index file

The index file is append-only.

+--------------------+
| RowId1 <-> Offset1 |
+--------------------+
| RowId2 <-> Offset2 |
+--------------------+
| RowId3 <-> Offset3 |
+--------------------+
|        ...         |

The row ID is assumed to grow contiguously, so it's not stored in the file.