Contrail analytics api query response time issue when querying 1d samples

Contrail analytics api query response time increase when the duration is increased, even though the number of samples returned is the same.

In a setup with UVE pushed for 5 days, we have observed that when the query is made for last 7 days ("start_time": "now-7d"), we see time take around 5 secs (returning around 208 samples).
When we do for last 31 days ("start_time": "now-31d"), we see time take around 25 secs (returning same 208 samples).

Query used:
{"select_fields": ["app_metrics_diff_link_1d.value.session_duration", "app_metrics_diff_link_1d.value.session_count", "app_metrics_diff_link_1d.value.total_bytes", "app_metrics_diff_link_1d.value.input_bytes", "app_metrics_diff_link_1d.value.output_bytes", "app_metrics_diff_link_1d.value.sla_violation_duration", "app_metrics_diff_link_1d.value.sla_violation_count", "app_metrics_diff_link_1d.value.session_switch_count", "app_metrics_diff_link_1d.value.jitter_violation_count", "app_metrics_diff_link_1d.value.rtt_violation_count", "app_metrics_diff_link_1d.value.pkt_loss_violation_count", "app_metrics_diff_link_1d.__key", "T", "name"], "start_time": "now-7d", "where": [[{"name": "name", "value": "", "op": 7}]], "end_time": "now", "table": "StatTable.SDWANMetricsRecord.app_metrics_diff_link_1d.value"}