Goal

Faster implementation of csv encoding/decoding for the specific case of ASCII documents, no UTF requirement.

One of the issues available in the Go London User Group Hacknight (July)

Reason

Working with large amounts of data coming from legacy applications where encoding is known to be ASCII. A big amount of time in encoding/csv is spent in rune-level operations which are not needed if data is known to be ASCII.

Proposed fix

Use the base code in encoding/csv, change runes for bytes

Result 1

~25% speed up

Subsequent fix

Inline buffer/bytes from go 1.9 source and use a larger base buffer

Result 2

~15% additional speed up. Not sure if because of inlining, 1.9 having a better bytes/buffer implementation, larger base buffer or all three reasons.

Comparison

go test -bench ReadReuseRecordLargeFields -benchtime=30s

BenchmarkReadReuseRecordLargeFields-4   	 1000000	     68351 ns/op	    2976 B/op	      12 allocs/op
PASS
ok  	normal_csv	69.011s

go test -bench ReadReuseRecordLargeFields -benchtime=30s
BenchmarkReadReuseRecordLargeFields-4   	 1000000	     38828 ns/op	    2976 B/op	      12 allocs/op
PASS
ok  	quickcsv	39.243s