terbshaeusser
47d4dcf042
git-subtree-dir: backend/go-sqlite3 git-subtree-split: 20826e87d8f061d0a7266562f43950ee06e2e9c0
89 lines
2.2 KiB
Go
89 lines
2.2 KiB
Go
// Copyright (C) 2019 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
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//
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// Use of this source code is governed by an MIT-style
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// license that can be found in the LICENSE file.
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//go:build cgo
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// +build cgo
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package sqlite3
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import (
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"context"
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"database/sql/driver"
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"fmt"
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"testing"
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)
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// BenchmarkStmtCache measures the stmt cache hit / miss / eviction paths by
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// cycling through a fixed set of queries under various cache sizes. It is
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// intended for comparing cache behavior changes, not for absolute numbers.
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func BenchmarkStmtCache(b *testing.B) {
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cases := []struct {
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name string
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cacheSize int
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keyCount int
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}{
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{"off", 0, 1}, // baseline: no cache
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{"size4_keys1_hit", 4, 1}, // trivial hit path
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{"size4_keys4_hit", 4, 4}, // all queries fit, always hit
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{"size4_keys8_evict", 4, 8}, // working set > cache: miss + eviction
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{"size16_keys8_hit", 16, 8}, // all queries fit in larger cache
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{"size16_keys32_evict", 16, 32}, // working set >> cache
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}
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for _, tc := range cases {
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b.Run(tc.name, func(b *testing.B) {
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dsn := ":memory:"
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if tc.cacheSize > 0 {
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dsn = fmt.Sprintf(":memory:?_stmt_cache_size=%d", tc.cacheSize)
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}
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d := SQLiteDriver{}
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conn, err := d.Open(dsn)
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if err != nil {
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b.Fatal(err)
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}
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defer conn.Close()
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c := conn.(*SQLiteConn)
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queries := make([]string, tc.keyCount)
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for i := range queries {
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// Distinct literal forces a distinct prepared statement.
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queries[i] = fmt.Sprintf("SELECT %d", i+1)
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}
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ctx := context.Background()
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// Warm up: exercise each query at least once so the cache (if any)
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// reaches steady state before timing begins.
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for _, q := range queries {
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rows, err := c.query(ctx, q, nil)
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if err != nil {
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b.Fatal(err)
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}
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drainRows(b, rows)
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}
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b.ReportAllocs()
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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q := queries[i%len(queries)]
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rows, err := c.query(ctx, q, nil)
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if err != nil {
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b.Fatal(err)
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}
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drainRows(b, rows)
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}
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})
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}
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}
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func drainRows(b *testing.B, rows driver.Rows) {
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b.Helper()
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dest := make([]driver.Value, len(rows.Columns()))
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for {
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if err := rows.Next(dest); err != nil {
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break
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}
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}
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rows.Close()
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}
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