README
¶
Go mvcc SQLite VFS
This package implements the "mvcc" in-memory SQLite VFS.
It has some benefits over the "memdb" VFS:
- panics do not corrupt a shared database,
- single-writer not blocked by readers,
- readers never block,
- instant snapshots.
mvcc.TestDB
is the preferred way to setup an in-memory database for testing
when you intend to leverage snapshots,
e.g. to setup many independent copies of a database,
such as one for each subtest.
Documentation
¶
Overview ¶
Package mvcc implements the "mvcc" SQLite VFS.
The "mvcc" vfs.VFS allows the same in-memory database to be shared among multiple database connections in the same process, as long as the database name begins with "/".
Importing package mvcc registers the VFS:
import _ "github.com/ncruces/go-sqlite3/vfs/mvcc"
Example ¶
package main
import (
"database/sql"
_ "embed"
"fmt"
"log"
_ "github.com/ncruces/go-sqlite3/driver"
"github.com/ncruces/go-sqlite3/vfs/mvcc"
)
//go:embed testdata/test.db
var testDB string
func main() {
mvcc.Create("test.db", mvcc.NewSnapshot(testDB))
db, err := sql.Open("sqlite3", "file:/test.db?vfs=mvcc")
if err != nil {
log.Fatal(err)
}
defer db.Close()
_, err = db.Exec(`INSERT INTO users (id, name) VALUES (3, 'rust')`)
if err != nil {
log.Fatal(err)
}
rows, err := db.Query(`SELECT id, name FROM users`)
if err != nil {
log.Fatal(err)
}
defer rows.Close()
for rows.Next() {
var id, name string
err = rows.Scan(&id, &name)
if err != nil {
log.Fatal(err)
}
fmt.Printf("%s %s\n", id, name)
}
if err := rows.Err(); err != nil {
log.Fatal(err)
}
}
Output: 0 go 1 zig 2 whatever 3 rust
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func TestDB ¶ added in v0.29.1
TestDB creates a shared database from a snapshot for the test to use. The database is automatically deleted when the test and all its subtests complete. Returns a URI filename appropriate to call Open with.
func Test_something(t *testing.T) {
t.Parallel()
dsn := mvcc.TestDB(t, snapshot, url.Values{
"_pragma": {"busy_timeout(1000)"},
})
db, err := sql.Open("sqlite3", dsn)
if err != nil {
t.Fatal(err)
}
defer db.Close()
// ...
}
Types ¶
type Snapshot ¶
Snapshot represents a database snapshot.
func NewSnapshot ¶ added in v0.29.1
NewSnapshot creates a snapshot from data.
func TakeSnapshot ¶ added in v0.29.1
TakeSnapshot takes a snapshot of a database. Name may be a URI filename.
Source Files