7e1661f4fa
This improves the performance of certain queries dramatically, such as 'count(*)' etc. Without this PR ``` ~ time mc select --query "select count(*) from S3Object" myminio/sjm-airlines/star2000.csv.gz 2173762 real 0m42.464s user 0m0.071s sys 0m0.010s ``` With this PR ``` ~ time mc select --query "select count(*) from S3Object" myminio/sjm-airlines/star2000.csv.gz 2173762 real 0m17.603s user 0m0.093s sys 0m0.008s ``` Almost a 250% improvement in performance. This PR avoids a lot of type conversions and instead relies on raw sequences of data and interprets them lazily. ``` benchcmp old new benchmark old ns/op new ns/op delta BenchmarkSQLAggregate_100K-4 551213 259782 -52.87% BenchmarkSQLAggregate_1M-4 6981901985 2432413729 -65.16% BenchmarkSQLAggregate_2M-4 13511978488 4536903552 -66.42% BenchmarkSQLAggregate_10M-4 68427084908 23266283336 -66.00% benchmark old allocs new allocs delta BenchmarkSQLAggregate_100K-4 2366 485 -79.50% BenchmarkSQLAggregate_1M-4 47455492 21462860 -54.77% BenchmarkSQLAggregate_2M-4 95163637 43110771 -54.70% BenchmarkSQLAggregate_10M-4 476959550 216906510 -54.52% benchmark old bytes new bytes delta BenchmarkSQLAggregate_100K-4 1233079 1086024 -11.93% BenchmarkSQLAggregate_1M-4 2607984120 557038536 -78.64% BenchmarkSQLAggregate_2M-4 5254103616 1128149168 -78.53% BenchmarkSQLAggregate_10M-4 26443524872 5722715992 -78.36% ``` |
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|---|---|---|
| .. | ||
| format | ||
| datatypes.go | ||
| errors.go | ||
| evaluate.go | ||
| helpers.go | ||
| input.go | ||
| output.go | ||
| select.go | ||
| select_test.go | ||