Remove buffer copy during cached Scan

Author: prashanthpai

README.md

@@ -6,14 +6,17 @@
 [![codecov](https://codecov.io/gh/prashanthpai/sqlcache/branch/master/graph/badge.svg)](https://codecov.io/gh/prashanthpai/sqlcache)
 [![MIT license](https://img.shields.io/badge/license-MIT-brightgreen.svg)](https://opensource.org/licenses/MIT)
 
-sqlcache is an **experimental** caching middleware for `database/sql`. It
-leverages APIs provided by the handy [sqlmw](https://github.com/ngrok/sqlmw)
+sqlcache is an **experimental** caching middleware for `database/sql`
+that enables existing Go programs to add caching in a declarative way.
+It leverages APIs provided by the handy [sqlmw](https://github.com/ngrok/sqlmw)
 project and is inspired from [slonik-interceptor-query-cache](https://github.com/gajus/slonik-interceptor-query-cache).
+
 This liberates your Go program from maintaining imperative code that
-implements the cache-aside pattern. Your program will perceive the
-database client/driver as a read-through cache.
+repeatedly implements the cache-aside pattern. Your program will perceive
+the database client/driver as a read-through cache.
 
-Tested with PostgreSQL database with [pgx](https://github.com/jackc/pgx/tree/master/stdlib) as the driver.
+Tested with PostgreSQL database with [pgx](https://github.com/jackc/pgx/tree/master/stdlib)
+as the underlying driver.
 
 Cache backends supported:
 
@@ -77,11 +80,6 @@ rows, err := db.QueryContext(context.TODO(), `
 
 See [example/main.go](example/main.go) for a full working example.
 
-## TODO
-
-* Test against different postgres data types.
-* Check if deep copy of buffers can be removed.
-
 ### References
 
 * A declarative way to cache PostgreSQL queries using Node.js: a [blog post](https://dev.to/gajus/a-declarative-way-to-cache-postgresql-queries-using-node-js-4fbo) by the author of [Slonik](https://github.com/gajus/slonik).

example/main.go

@@ -91,7 +91,7 @@ func run() error {
 		return fmt.Errorf("db.PingContext() failed: %w", err)
 	}
 
-	for i := 0; i < 3; i++ {
+	for i := 0; i < 15; i++ {
 		start := time.Now()
 		if err := doQuery(db); err != nil {
 			return fmt.Errorf("doQuery() failed: %w", err)

recorder.go

@@ -66,7 +66,7 @@ func (r *rowsRecorder) Next(dest []driver.Value) error {
 	}
 
 	cpy := make([]driver.Value, len(dest))
-	copy(cpy, dest) // TODO: deep copy required ?
+	copy(cpy, dest)
 	r.item.Rows = append(r.item.Rows, cpy)
 
 	return err

rows_cached.go

@@ -22,7 +22,9 @@ func (r *rowsCached) Next(dest []driver.Value) error {
 		return io.EOF
 	}
 
-	copy(dest, r.Item.Rows[r.ptr]) // copy required ?
+	for i := range dest {
+		dest[i] = r.Item.Rows[r.ptr][i]
+	}
 	r.ptr++
 
 	return nil