Use DBLoader when loading Dolt environment.

go/cmd/dolt/dolt.go

@@ -417,7 +417,7 @@ func runMain() int {
 	args = nil
 
 	// This is the dEnv passed to sub-commands, and is used to create the multi-repo environment.
-	dEnv := env.LoadWithoutDB(ctx, env.GetCurrentUserHomeDir, cfg.dataDirFS, doltdb.LocalDirDoltDB, doltversion.Version)
+	dEnv := env.Load(ctx, env.GetCurrentUserHomeDir, cfg.dataDirFS, doltdb.LocalDirDoltDB, doltversion.Version)
 
 	if dEnv.CfgLoadErr != nil {
 		cli.PrintErrln(color.RedString("Failed to load the global config. %v", dEnv.CfgLoadErr))
@@ -678,11 +678,8 @@ If you're interested in running this command against a remote host, hit us up on
 	}
 
 	var lookForServer bool
-	if targetEnv.DoltDB(ctx) != nil && targetEnv.IsAccessModeReadOnly(ctx) {
-		// If the loaded target environment has a doltDB and we do not
-		// have access to it, we look for a server.
-		lookForServer = true
-	} else if targetEnv.DoltDB(ctx) == nil {
+
+	if !targetEnv.Exists() {
 		// If the loaded environment itself does not have a doltDB, we
 		// may want to look for a server. We do so if all of the
 		// repositories in our MultiEnv are ReadOnly. This includes the
@@ -695,6 +692,10 @@ If you're interested in running this command against a remote host, hit us up on
 			return !allReposAreReadOnly, nil
 		})
 		lookForServer = allReposAreReadOnly
+	} else if targetEnv.IsAccessModeReadOnly(ctx) {
+		// If the loaded target environment has a doltDB and we do not
+		// have access to it, we look for a server.
+		lookForServer = true
 	}
 	if lookForServer {
 		localCreds, err := sqlserver.FindAndLoadLocalCreds(targetEnv.FS)

go/libraries/doltcore/env/environment.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"github.com/dolthub/dolt/go/store/chunks"
 	"os"
 	"path/filepath"
 	"strings"
@@ -37,7 +38,6 @@ import (
 	"github.com/dolthub/dolt/go/libraries/utils/concurrentmap"
 	"github.com/dolthub/dolt/go/libraries/utils/config"
 	"github.com/dolthub/dolt/go/libraries/utils/filesys"
-	"github.com/dolthub/dolt/go/store/chunks"
 	"github.com/dolthub/dolt/go/store/datas"
 	"github.com/dolthub/dolt/go/store/hash"
 	"github.com/dolthub/dolt/go/store/types"
@@ -88,6 +88,7 @@ type DoltEnv struct {
 	RepoState *RepoState
 	RSLoadErr error
 
+	dbLoader    dbfactory.DBLoader
 	loadDBOnce  sync.Once
 	doltDB      *doltdb.DoltDB
 	DBLoadError error
@@ -203,13 +204,14 @@ func LoadWithoutDB(_ context.Context, hdp HomeDirProvider, fs filesys.Filesys, u
 // Load loads the DoltEnv for the .dolt directory determined by resolving the specified urlStr with the specified Filesys.
 func Load(ctx context.Context, hdp HomeDirProvider, fs filesys.Filesys, urlStr string, version string) *DoltEnv {
 	dEnv := LoadWithoutDB(ctx, hdp, fs, urlStr, version)
-	LoadDoltDB(ctx, dEnv.FS, dEnv.urlStr, dEnv)
+	dEnv.dbLoader, dEnv.DBLoadError = doltdb.GetDBLoader(ctx, types.Format_Default, urlStr, fs)
+
 	return dEnv
 }
 
 func LoadDoltDB(ctx context.Context, fs filesys.Filesys, urlStr string, dEnv *DoltEnv) {
 	dEnv.loadDBOnce.Do(func() {
-		ddb, dbLoadErr := doltdb.LoadDoltDB(ctx, types.Format_Default, urlStr, fs)
+		ddb, dbLoadErr := doltdb.LoadDB(ctx, dEnv.dbLoader, urlStr)
 		dEnv.doltDB = ddb
 		dEnv.DBLoadError = dbLoadErr
 		dEnv.urlStr = urlStr
@@ -1269,6 +1271,13 @@ func (dEnv *DoltEnv) BulkDbEaFactory(ctx context.Context) editor.DbEaFactory {
 	return editor.NewBulkImportTEAFactory(dEnv.DoltDB(ctx).ValueReadWriter(), tmpDir)
 }
 
+func (dEnv *DoltEnv) Exists() bool {
+	return dEnv.dbLoader != nil || dEnv.doltDB != nil
+}
+
 func (dEnv *DoltEnv) IsAccessModeReadOnly(ctx context.Context) bool {
+	if dEnv.dbLoader != nil {
+		return dEnv.dbLoader.IsAccessModeReadOnly()
+	}
 	return dEnv.DoltDB(ctx).AccessMode() == chunks.ExclusiveAccessMode_ReadOnly
 }

go/libraries/doltcore/env/multi_repo_env.go

@@ -187,7 +187,7 @@ func MultiEnvForDirectory(
 			version = dEnv.Version
 		}
 
-		newEnv := LoadWithoutDB(ctx, GetCurrentUserHomeDir, newFs, doltdb.LocalDirDoltDB, version)
+		newEnv := Load(ctx, GetCurrentUserHomeDir, newFs, doltdb.LocalDirDoltDB, version)
 		if newEnv.Valid() {
 			envSet[dbfactory.DirToDBName(dir)] = newEnv
 		} else {
@@ -246,7 +246,12 @@ func (mrEnv *MultiRepoEnv) ReloadDBs(
 			}
 		}
 	}
-	mrEnv.envs = enforceSingleFormat(ctx, mrEnv.envs)
+	// We can skip the format check if there's only one environment.
+	// This is vital because it allows us to defer loading the database if there's only one.
+	// TODO: Can we determine the format without loading the database?
+	if len(mrEnv.envs) > 1 {
+		mrEnv.envs = enforceSingleFormat(ctx, mrEnv.envs)
+	}
 }
 
 func (mrEnv *MultiRepoEnv) FileSystem() filesys.Filesys {

go/store/nbs/file_manifest.go

@@ -95,8 +95,7 @@ func MaybeMigrateFileManifest(ctx context.Context, dir string) (bool, error) {
 }
 
 // getFileManifest makes a new file manifest.
-func getFileManifest(ctx context.Context, dir string, mode updateMode) (m manifest, err error) {
-	lock := fslock.New(filepath.Join(dir, lockFileName))
+func getFileManifest(ctx context.Context, lock *fslock.Lock, dir string, mode updateMode) (m manifest, err error) {
 	m = fileManifest{dir: dir, mode: mode, lock: lock}
 
 	var f *os.File