Hire Oracle PL/SQL Developers

A surprising share of an enterprise estate’s actual business logic lives in PL/SQL, written over a decade by people who have since left, running at two in the morning. It is rarely on anyone’s architecture diagram and it is invariably on the critical path.

The work divides into three. The first is comprehension: a four-thousand-line package with no tests, which must keep behaving exactly as it does while something inside it changes. Writing characterisation tests around the current behaviour before touching it is slower on day one and is the only approach that does not produce a silent regression.

The second is performance, and it is nearly always the same cause. Row-by-row processing — a cursor loop performing a select and an update per row — is fast enough in test and fails in production because production has forty million rows rather than four hundred. Rewriting it as a set operation is usually a tenfold improvement before anyone looks at an index. Reaching for the index first is the common instinct and rarely the answer.

The third is the interface layer: staging tables, error tables and reprocessing. Batches are re-run — because a file arrived late, because someone fixed a mapping, because the first attempt half-finished. If reprocessing is not idempotent, the second run inserts the same rows again. This is the single most common cause of a reconciliation break we are asked to investigate, and it is entirely preventable at design time.