// restoreTable inserts the given DatabaseDescriptor. If the name conflicts with
// an existing table, the one being restored is rekeyed with a new ID and the
// old data is deleted.
func restoreTable(
ctx context.Context,
db client.DB,
database sqlbase.DatabaseDescriptor,
table *sqlbase.TableDescriptor,
ranges []sqlbase.BackupRangeDescriptor,
) error {
if log.V(1) {
log.Infof(ctx, "Restoring Table %q", table.Name)
}
var newTableID sqlbase.ID
if err := db.Txn(ctx, func(txn *client.Txn) error {
// Make sure there's a database with a name that matches the original.
if _, err := getDescriptorID(txn, tableKey{name: database.Name}); err != nil {
return errors.Wrapf(err, "a database named %q needs to exist to restore table %q",
database.Name, table.Name)
}
// Assign a new ID for the table. TODO(dan): For now, we're always
// generating a new ID, but varints get longer as they get bigger and so
// our keys will, too. We should someday figure out how to overwrite an
// existing table and steal its ID.
var err error
newTableID, err = GenerateUniqueDescID(txn)
return err
}); err != nil {
return err
}
// Create the iteration keys before we give the table its new ID.
tableStartKeyOld := roachpb.Key(sqlbase.MakeIndexKeyPrefix(table, table.PrimaryIndex.ID))
tableEndKeyOld := tableStartKeyOld.PrefixEnd()
// This loop makes restoring multiple tables O(N*M), where N is the number
// of tables and M is the number of ranges. We could reduce this using an
// interval tree if necessary.
var wg sync.WaitGroup
result := struct {
syncutil.Mutex
firstErr error
numErrs int
}{}
for _, rangeDesc := range ranges {
if len(rangeDesc.Path) == 0 {
// Empty path means empty range.
continue
}
intersectBegin, intersectEnd := IntersectHalfOpen(
rangeDesc.StartKey, rangeDesc.EndKey, tableStartKeyOld, tableEndKeyOld)
if intersectBegin != nil && intersectEnd != nil {
// Write the data under the new ID.
// TODO(dan): There's no SQL descriptors that point at this yet, so it
// should be possible to remove it from the one txn this is all currently
// run under. If we do that, make sure this data gets cleaned up on errors.
wg.Add(1)
go func(desc sqlbase.BackupRangeDescriptor) {
for r := retry.StartWithCtx(ctx, base.DefaultRetryOptions()); r.Next(); {
err := db.Txn(ctx, func(txn *client.Txn) error {
return Ingest(ctx, txn, desc.Path, desc.CRC, intersectBegin, intersectEnd, newTableID)
})
if _, ok := err.(*client.AutoCommitError); ok {
log.Errorf(ctx, "auto commit error during ingest: %s", err)
// TODO(dan): Ingest currently does not rely on the
// range being empty, but the plan is that it will. When
// that change happens, this will have to delete any
// partially ingested data or something.
continue
}
if err != nil {
log.Errorf(ctx, "%T %s", err, err)
result.Lock()
defer result.Unlock()
if result.firstErr != nil {
result.firstErr = err
}
result.numErrs++
}
break
}
wg.Done()
}(rangeDesc)
}
}
wg.Wait()
// All concurrent accesses have finished, we don't need the lock anymore.
if result.firstErr != nil {
// This leaves the data that did get imported in case the user wants to
// retry.
// TODO(dan): Build tooling to allow a user to restart a failed restore.
return errors.Wrapf(result.firstErr, "ingest encountered %d errors", result.numErrs)
}
table.ID = newTableID
return db.Txn(ctx, func(txn *client.Txn) error {
// Pass the descriptors by value to keep this idempotent.
return restoreTableDesc(ctx, txn, database, *table)
})
}
