Sending the ExecPlanFragment to remote nodes dominates the query startup time on clusters larger than 100 nodes, size of the ExecPlanFragment grows with number of tables, blocks and partitions in the table.
On large cluster this is limits query throughput.
From TPC-DS Q11 on 1K node cluster
Query Timeline: 5m6s
- Query submitted: 75.256us (75.256us)
- Planning finished: 1s580ms (1s580ms)
- Submit for admission: 2s376ms (795.652ms)
- Completed admission: 2s377ms (1.512ms)
- Ready to start 15993 fragment instances: 2s458ms (80.378ms)
- First dynamic filter received: 2m35s (2m33s)
- All 15993 fragment instances started: 2m35s (40.934ms)
- Rows available: 4m53s (2m17s)
- First row fetched: 4m53s (176.254ms)
- Unregister query: 4m58s (4s828ms)
- ComputeScanRangeAssignmentTimer: 600.086ms