When migrating a schema from Oracle to PostgreSQL, indexes need careful review. Indexes may look similar across both platforms, but their features, syntax, and performance behavior are not always the same.

Both Oracle and PostgreSQL support indexes for improving query performance, but teams should not assume every Oracle index can be moved directly. PostgreSQL handles common B-tree indexes well, and descending indexes are also supported. However, Oracle-specific features such as reverse key indexes, bitmap indexes, and join indexes do not map directly in PostgreSQL and may need a different design approach.

It is also important to understand that PostgreSQL does not use global indexes the same way Oracle can in partitioned environments. In PostgreSQL, indexes are generally created at the table or partition level, so partition strategy and query pattern must be reviewed together. Expression indexes, partial indexes, and multicolumn indexes in PostgreSQL can often help replace Oracle-specific indexing patterns, but the right choice depends on actual workload and execution plans.

What to Review During Index Migration

Index migration should always include testing. After schema conversion, teams should run high-value queries, compare execution plans, and measure response time under realistic load. In many migrations, the best result comes from redesigning indexes for PostgreSQL rather than copying Oracle structures as-is. A thoughtful review of index usage can improve performance, reduce storage overhead, and make the target system easier to maintain.