feat: added indexes to make querying performant (#17)

Author: robbert229

internal/sql/migrations/002_indexes.sql

@@ -0,0 +1,20 @@
+
+-- +goose Up
+
+CREATE INDEX IF NOT EXISTS idx_trace_id ON spans (trace_id);
+CREATE INDEX IF NOT EXISTS idx_services_name ON services(name);
+CREATE INDEX IF NOT EXISTS idx_operations_name ON operations(name);
+CREATE INDEX IF NOT EXISTS idx_spans_operation_service ON spans(operation_id, service_id);
+CREATE INDEX IF NOT EXISTS idx_spans_start_duration ON spans(start_time, duration);
+CREATE INDEX IF NOT EXISTS idx_spans_start_time ON spans(start_time);
+CREATE INDEX IF NOT EXISTS idx_spans_duration ON spans(duration);
+
+-- +goose Down
+
+DROP INDEX idx_trace_id ON spans (trace_id);
+DROP INDEX idx_services_name ON services(name);
+DROP INDEX idx_operations_name ON operations(name);
+DROP INDEX idx_spans_operation_service ON spans(operation_id, service_id);
+DROP INDEX idx_spans_start_duration ON spans(start_time, duration);
+DROP INDEX idx_spans_start_time ON spans(start_time);
+DROP INDEX idx_spans_duration ON spans(duration);