etl

Data import/export moves data between systems. I use COPY for bulk operations—orders of magnitude faster than INSERT. CSV format balances simplicity and performance. Binary format is faster but less portable. Streaming import handles large files witho

Spring Batch handles large-scale batch processing—ETL, data migration, report generation. Jobs contain steps; steps have readers, processors, and writers. Chunk-oriented processing reads, processes, and writes data in configurable batches. ItemReader