minio/pkg/s3select/format/select.go
Harshavardhana 7e1661f4fa Performance improvements to SELECT API on certain query operations (#6752)
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%
```
2018-11-14 15:55:10 -08:00

64 lines
1.9 KiB
Go

/*
* Minio Cloud Storage, (C) 2018 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package format
import "encoding/xml"
// Select Interface helper methods, implementing features needed for
// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectSELECTContent.html
type Select interface {
Type() Type
Read() ([]byte, error)
Header() []string
HasHeader() bool
OutputFieldDelimiter() string
UpdateBytesProcessed(int64)
Expression() string
UpdateBytesReturned(int64)
CreateStatXML() (string, error)
CreateProgressXML() (string, error)
ColNameErrs(columnNames []string) error
Progress() bool
}
// Progress represents a struct that represents the format for XML of the
// progress messages
type Progress struct {
XMLName xml.Name `xml:"Progress" json:"-"`
BytesScanned int64 `xml:"BytesScanned"`
BytesProcessed int64 `xml:"BytesProcessed"`
BytesReturned int64 `xml:"BytesReturned"`
}
// Stats represents a struct that represents the format for XML of the stat
// messages
type Stats struct {
XMLName xml.Name `xml:"Stats" json:"-"`
BytesScanned int64 `xml:"BytesScanned"`
BytesProcessed int64 `xml:"BytesProcessed"`
BytesReturned int64 `xml:"BytesReturned"`
}
// Type different types of support data format types.
type Type string
// Different data format types.
const (
JSON Type = "json"
CSV Type = "csv"
)