andygrove opened a new issue #871: URL: https://github.com/apache/arrow-datafusion/issues/871
**Is your feature request related to a problem or challenge? Please describe what you are trying to do.** When running the benchmarks with DataFusion I noticed that we scan statistics for all tables early on (even tables not referenced in the query). This happens in `ExecutionContext::register_table`. We then scan statistics again later on for the tables that are actually used in the query. ``` ../target/release/tpch benchmark datafusion --path /mnt/bigdata/tpch-sf1000-parquet/ --format parquet --iterations 1 --debug --concurrency 24 --query 3 Running benchmarks with the following options: DataFusionBenchmarkOpt { query: 3, debug: true, iterations: 1, concurrency: 24, batch_size: 8192, path: "/mnt/bigdata/tpch-sf1000-parquet/", file_format: "parquet", mem_table: false, partitions: 8 } ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//part) Scanned 48 Parquet files for statistics in 0 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//supplier) Scanned 48 Parquet files for statistics in 0 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//partsupp) Scanned 48 Parquet files for statistics in 1 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//customer) Scanned 48 Parquet files for statistics in 0 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//orders) Scanned 48 Parquet files for statistics in 4 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//lineitem) Scanned 48 Parquet files for statistics in 30 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//nation) Scanned 1 Parquet files for statistics in 0 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//region) Scanned 1 Parquet files for statistics in 0 seconds === Logical plan === Sort: #revenue DESC NULLS FIRST, #orders.o_orderdate ASC NULLS FIRST Projection: #lineitem.l_orderkey, #SUM(lineitem.l_extendedprice Multiply Int64(1) Minus lineitem.l_discount) AS revenue, #orders.o_orderdate, #orders.o_shippriority Aggregate: groupBy=[[#lineitem.l_orderkey, #orders.o_orderdate, #orders.o_shippriority]], aggr=[[SUM(#lineitem.l_extendedprice Multiply Int64(1) Minus #lineitem.l_discount)]] Filter: #customer.c_mktsegment Eq Utf8("BUILDING") And #orders.o_orderdate Lt CAST(Utf8("1995-03-15") AS Date32) And #lineitem.l_shipdate Gt CAST(Utf8("1995-03-15") AS Date32) Join: #orders.o_orderkey = #lineitem.l_orderkey Join: #customer.c_custkey = #orders.o_custkey TableScan: customer projection=None TableScan: orders projection=None TableScan: lineitem projection=None === Optimized logical plan === Sort: #revenue DESC NULLS FIRST, #orders.o_orderdate ASC NULLS FIRST Projection: #lineitem.l_orderkey, #SUM(lineitem.l_extendedprice Multiply Int64(1) Minus lineitem.l_discount) AS revenue, #orders.o_orderdate, #orders.o_shippriority Aggregate: groupBy=[[#lineitem.l_orderkey, #orders.o_orderdate, #orders.o_shippriority]], aggr=[[SUM(#lineitem.l_extendedprice Multiply Int64(1) Minus #lineitem.l_discount)]] Join: #orders.o_orderkey = #lineitem.l_orderkey Join: #customer.c_custkey = #orders.o_custkey Filter: #customer.c_mktsegment Eq Utf8("BUILDING") TableScan: customer projection=Some([0, 6]), filters=[#customer.c_mktsegment Eq Utf8("BUILDING")] Filter: #orders.o_orderdate Lt Date32("9204") TableScan: orders projection=Some([0, 1, 4, 7]), filters=[#orders.o_orderdate Lt Date32("9204")] Filter: #lineitem.l_shipdate Gt Date32("9204") TableScan: lineitem projection=Some([0, 5, 6, 10]), filters=[#lineitem.l_shipdate Gt Date32("9204")] ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//customer) Scanned 48 Parquet files for statistics in 0 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//orders) Scanned 48 Parquet files for statistics in 4 seconds ParquetExec::try_from_path(/mnt/bigdata/tpch-sf1000-parquet//lineitem) Scanned 48 Parquet files for statistics in 30 seconds === Physical plan === SortExec: [revenue@1 DESC,o_orderdate@2 ASC] CoalescePartitionsExec ProjectionExec: expr=[l_orderkey@0 as l_orderkey, SUM(lineitem.l_extendedprice Multiply Int64(1) Minus lineitem.l_discount)@3 as revenue, o_orderdate@1 as o_orderdate, o_shippriority@2 as o_shippriority] HashAggregateExec: mode=FinalPartitioned, gby=[l_orderkey@0 as l_orderkey, o_orderdate@1 as o_orderdate, o_shippriority@2 as o_shippriority], aggr=[SUM(l_extendedprice Multiply Int64(1) Minus l_discount)] CoalesceBatchesExec: target_batch_size=4096 RepartitionExec: partitioning=Hash([Column { name: "l_orderkey", index: 0 }, Column { name: "o_orderdate", index: 1 }, Column { name: "o_shippriority", index: 2 }], 24) HashAggregateExec: mode=Partial, gby=[l_orderkey@6 as l_orderkey, o_orderdate@4 as o_orderdate, o_shippriority@5 as o_shippriority], aggr=[SUM(l_extendedprice Multiply Int64(1) Minus l_discount)] CoalesceBatchesExec: target_batch_size=4096 HashJoinExec: mode=Partitioned, join_type=Inner, on=[(Column { name: "o_orderkey", index: 2 }, Column { name: "l_orderkey", index: 0 })] CoalesceBatchesExec: target_batch_size=4096 RepartitionExec: partitioning=Hash([Column { name: "o_orderkey", index: 2 }], 24) CoalesceBatchesExec: target_batch_size=4096 HashJoinExec: mode=Partitioned, join_type=Inner, on=[(Column { name: "c_custkey", index: 0 }, Column { name: "o_custkey", index: 1 })] CoalesceBatchesExec: target_batch_size=4096 RepartitionExec: partitioning=Hash([Column { name: "c_custkey", index: 0 }], 24) CoalesceBatchesExec: target_batch_size=4096 FilterExec: c_mktsegment@1 = BUILDING ParquetExec: batch_size=8192, limit=None, partitions=[...] CoalesceBatchesExec: target_batch_size=4096 RepartitionExec: partitioning=Hash([Column { name: "o_custkey", index: 1 }], 24) CoalesceBatchesExec: target_batch_size=4096 FilterExec: o_orderdate@2 < 9204 ParquetExec: batch_size=8192, limit=None, partitions=[...] CoalesceBatchesExec: target_batch_size=4096 RepartitionExec: partitioning=Hash([Column { name: "l_orderkey", index: 0 }], 24) CoalesceBatchesExec: target_batch_size=4096 FilterExec: l_shipdate@3 > 9204 ParquetExec: batch_size=8192, limit=None, partitions=[...] ``` **Describe the solution you'd like** - We should only scan statistics for tables that are used in the query - We should only scan statistics once **Describe alternatives you've considered** N/A **Additional context** N/A -- This is an automated message from the Apache Git Service. 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