Remove unneeded string to []byte to string conversion, which saves 2
allocs and should make Hstore text scanning slightly faster.
The Hstore.Scan() function takes a string as input, converts it to
[]byte, and calls scanPlanTextAnyToHstoreScanner.Scan(). That
function converts []byte back to string and calls parseHstore. This
refactors scanPlanTextAnyToHstoreScanner.Scan into
scanPlanTextAnyToHstoreScanner.scanString so the database/sql Scan
function can call it directly, bypassing this conversion.
The added Benchmark shows this saves 2 allocs for longer strings, and
saves about 5% CPU overall on my M1 Pro. benchstat output:
goos: darwin
goarch: arm64
pkg: github.com/jackc/pgx/v5/pgtype
│ orig.txt │ new.txt │
│ sec/op │ sec/op vs base │
HstoreScan-10 1.334µ ± 2% 1.257µ ± 2% -5.77% (p=0.000 n=10)
│ orig.txt │ new.txt │
│ B/op │ B/op vs base │
HstoreScan-10 2.094Ki ± 0% 1.969Ki ± 0% -5.97% (p=0.000 n=10)
│ orig.txt │ new.txt │
│ allocs/op │ allocs/op vs base │
HstoreScan-10 36.00 ± 0% 34.00 ± 0% -5.56% (p=0.000 n=10)
Evan Jones
1b68b5970e