A filter translates a business rule. Write this rule as a sentence before converting it to SQL: Paid orders, created during July, with an amount of at least €100. Each word influences the operator and the limits.
Adding indexes everywhere slows down writes and consumes space. The useful index depends on the filters, joins, sorts, volumes and selectivity of an actual query.
Capture the slow query, use EXPLAIN then EXPLAIN ANALYZE on a safe environment, compare estimates and actual rows, and create the smallest index that serves the critical path.
Measure before/after with representative data. Check the total time, readings, usage frequency and cost of the INSERT/UPDATE, not just the presence of an Index Scan.
Create a targeted index and then verify its presence before interpreting a plan. You must produce the result, check it on the source data and explain what it allows you to decide in this billing system.
Create a targeted index and then verify its presence before interpreting a plan. You must produce the result, check it on the source data and explain what it allows you to decide in this national expeditions.
Create a targeted index and then verify its presence before interpreting a plan. You must produce the result, control it on the source data and explain what it allows you to decide in this human resources management.
Create a targeted index and then verify its presence before interpreting a plan. You must produce the result, check it on the source data and explain what it allows you to decide in this audit log.