Parquet, Avro and ORC are the file formats of data lakes. Lima reads them with their embedded schemas, handles schema evolution between files, and writes Parquet as its default landing format.
Each method has a job. The first load uses the bulk method; the daily run uses the incremental or change-capture method; write-back uses the interface the system itself uses.
| Method | What it does | When it is used |
|---|---|---|
| Schema-aware reads | Reads with embedded schemas; merges evolved schemas. | Lake files. |
| Parquet writes | Writes partitioned Parquet. | Landing. |
The objects are the tables, views or records Lima reaches through the methods above. The patterns say how a copy is made and kept current.
| Object | Plain meaning |
|---|---|
| Files and partitions | on object storage or HDFS |
| Pattern | Supported |
|---|---|
| Full load | Yes |
| Incremental | new files or partitions |
| Change capture | — |
| Streaming | — |
| Write-back | files written |
The prerequisites are what the team that runs Parquet, Avro and ORC files grants. The four steps are the same for every connector.
Incoming data = valid records + exception records. A row that fails a check is kept, routed to the person who owns it with a deadline, and replayed once fixed. The load carries on with the valid rows and the report says exactly what was held back. How exceptions work →
Lima connects from outside through the interfaces listed above with credentials your administrators grant. Where a vendor requires its own agent or add-on for a method, the prerequisites say so.
Parallel reads are capped and the cap is agreed with the team that runs the system. Large reads run inside an agreed run window. Change capture keeps the daily volume small.
A report per run: rows in, rows out, control totals and variance per table, the exceptions held back and who owns them, and whether the deadline was met.
Yes. Most estates start with one source, one target and one dataset, then add tables and patterns on the same connection.
A trial connects this system, runs a first load and ends with a reconciliation report. Your administrators see the prerequisites before anything is installed.
