Preparestmt use LRU Map instead default map

[Yaccc]

GROM default map may be cause memory leak

What did this pull request do?

PrepareStmt support use lrumap instead default Map
PreparedStmtDB stmt change to interface to defined maps

type StmtStore interface {
	Get(key string) (*Stmt, bool)
	Set(key string, value *Stmt)
	Delete(key string)
	AllMap() map[string]*Stmt
}

func NewPreparedStmtDB(connPool ConnPool, prepareStmtLruConfig *PrepareStmtLruConfig) *PreparedStmtDB {
	return &PreparedStmtDB{
		ConnPool: connPool,
		Stmts: func() StmtStore {
			var stmts StmtStore
			if prepareStmtLruConfig != nil && prepareStmtLruConfig.Open {
				lru := &LruStmtStore{}
				lru.NewLru(prepareStmtLruConfig.Size, prepareStmtLruConfig.TTL)
				stmts = lru
			} else {
				stmts = &DefaultStmtStore{}
			}
			return stmts
		}(),
		Mux: &sync.RWMutex{},
	}
}

1. original maps use defaultStmtStore,lur maps use LruStmtStore
2. PrepareStmtLruConfig init lru size and expired time
3. size must lt zero ande default ttl is

const noEvictionTTL = time.Hour * 24 * 365 * 10

const DEFAULT_MAX_SIZE = (1 << 63) - 1
const DEFAULT_TTL = time.Hour * 24
	// PrepareStmt cache support LRU expired
	PrepareStmtMaxSize int
	PrepareStmtTTL     time.Duration

User Case Description

TestPreparedStmtLruFromTransaction check lru active

conn, ok := tx.ConnPool.(*gorm.PreparedStmtDB)
	lens := len(conn.Stmts.AllMap())
	if lens == 0 {
		t.Fatalf("lru should not be empty")
	}
	time.Sleep(time.Second * 40)
	AssertEqual(t, ok, true)
	AssertEqual(t, len(conn.Stmts.AllMap()), 0)

[jinzhu]

This is no longer needed?

[Yaccc]

already deleted

[jinzhu]

Do we need to allow session-level configuration? For example, configure it here: https://github.com/go-gorm/gorm/blob/master/gorm.go#L107

[Yaccc]

if config.PrepareStmt {
		preparedStmt := NewPreparedStmtDB(db.ConnPool, config.PrepareStmtMaxSize, config.PrepareStmtTTL)
		db.cacheStore.Store(preparedStmtDBKey, preparedStmt)
		db.ConnPool = preparedStmt
	}

session default use static config

[jinzhu]

Could we relocate the majority of the following code to an internal package, such as internal/stmt_store, to prevent the exposure of additional structs or methods?

[Yaccc]

cause circular dependency

[iTanken]

Build failed in 32bit environment

a827495#r155931475

GOARCH=386 go test -timeout 20m -v ./...
  shell: /usr/bin/bash -e {0}
# gorm.io/gorm/internal/stmt_store
Error: 
../../../go/pkg/mod/gorm.io/[email protected]/internal/stmt_store/stmt_store.go:99:10: 
cannot use defaultMaxSize (untyped int constant 9223372036854775807) as int value in assignment (overflows)

[andig]

We've just hit this as well in #7442. A .1 release would be highly appreciated.