// Exec executes fn in the context of a distributed transaction.
// Execution is controlled by opt (see comments in TxnExecOptions).
//
// opt is passed to fn, and it's valid for fn to modify opt as it sees
// fit during each execution attempt.
//
// It's valid for txn to be nil (meaning the txn has already aborted) if fn
// can handle that. This is useful for continuing transactions that have been
// aborted because of an error in a previous batch of statements in the hope
// that a ROLLBACK will reset the state. Neither opt.AutoRetry not opt.AutoCommit
// can be set in this case.
//
// If an error is returned, the txn has been aborted.
func (txn *Txn) Exec(
opt TxnExecOptions,
fn func(txn *Txn, opt *TxnExecOptions) *roachpb.Error) *roachpb.Error {
// Run fn in a retry loop until we encounter a success or
// error condition this loop isn't capable of handling.
var pErr *roachpb.Error
var retryOptions retry.Options
if txn == nil && (opt.AutoRetry || opt.AutoCommit) {
panic("asked to retry or commit a txn that is already aborted")
}
if opt.AutoRetry {
retryOptions = txn.db.txnRetryOptions
}
RetryLoop:
for r := retry.Start(retryOptions); r.Next(); {
pErr = fn(txn, &opt)
if (pErr == nil) && opt.AutoCommit && (txn.Proto.Status == roachpb.PENDING) {
// fn succeeded, but didn't commit.
pErr = txn.commit(nil)
}
if pErr == nil {
break
}
// Make sure the txn record that pErr carries is for this txn.
// We check only when txn.Proto.ID has been initialized after an initial successful send.
if pErr.GetTxn() != nil && txn.Proto.ID != nil {
if errTxn := pErr.GetTxn(); !errTxn.Equal(&txn.Proto) {
return roachpb.NewErrorf("mismatching transaction record in the error:\n%s\nv.s.\n%s",
errTxn, txn.Proto)
}
}
if !opt.AutoRetry {
break RetryLoop
}
switch pErr.TransactionRestart {
case roachpb.TransactionRestart_IMMEDIATE:
r.Reset()
case roachpb.TransactionRestart_BACKOFF:
default:
break RetryLoop
}
if log.V(2) {
log.Infof("automatically retrying transaction: %s because of error: %s",
txn.DebugName(), pErr)
}
}
if txn != nil {
// TODO(andrei): don't do Cleanup() on retriable errors here.
// Let the sql executor do it.
txn.Cleanup(pErr)
}
if pErr != nil {
pErr.StripErrorTransaction()
}
return pErr
}
// Exec executes fn in the context of a distributed transaction.
// Execution is controlled by opt (see comments in TxnExecOptions).
//
// opt is passed to fn, and it's valid for fn to modify opt as it sees
// fit during each execution attempt.
//
// It's valid for txn to be nil (meaning the txn has already aborted) if fn
// can handle that. This is useful for continuing transactions that have been
// aborted because of an error in a previous batch of statements in the hope
// that a ROLLBACK will reset the state. Neither opt.AutoRetry not opt.AutoCommit
// can be set in this case.
//
// When this method returns, txn might be in any state; Exec does not attempt
// to clean up the transaction before returning an error. In case of
// TransactionAbortedError, txn is reset to a fresh transaction, ready to be
// used.
//
// TODO(andrei): Make Exec() return error; make fn return an error + a retriable
// bit. There's no reason to propagate roachpb.Error (protos) above this point.
func (txn *Txn) Exec(
opt TxnExecOptions,
fn func(txn *Txn, opt *TxnExecOptions) *roachpb.Error) *roachpb.Error {
// Run fn in a retry loop until we encounter a success or
// error condition this loop isn't capable of handling.
var pErr *roachpb.Error
var retryOptions retry.Options
if txn == nil && (opt.AutoRetry || opt.AutoCommit) {
panic("asked to retry or commit a txn that is already aborted")
}
if opt.AutoRetry {
retryOptions = txn.db.txnRetryOptions
}
RetryLoop:
for r := retry.Start(retryOptions); r.Next(); {
if txn != nil {
// If we're looking at a brand new transaction, then communicate
// what should be used as initial timestamp for the KV txn created
// by TxnCoordSender.
if txn.Proto.OrigTimestamp == roachpb.ZeroTimestamp {
txn.Proto.OrigTimestamp = opt.MinInitialTimestamp
}
}
pErr = fn(txn, &opt)
if txn != nil {
txn.retrying = true
defer func() {
txn.retrying = false
}()
}
if (pErr == nil) && opt.AutoCommit && (txn.Proto.Status == roachpb.PENDING) {
// fn succeeded, but didn't commit.
pErr = txn.Commit()
}
if pErr == nil {
break
}
// Make sure the txn record that pErr carries is for this txn.
// We check only when txn.Proto.ID has been initialized after an initial successful send.
if pErr.GetTxn() != nil && txn.Proto.ID != nil {
if errTxn := pErr.GetTxn(); !errTxn.Equal(&txn.Proto) {
return roachpb.NewErrorf("mismatching transaction record in the error:\n%s\nv.s.\n%s",
errTxn, txn.Proto)
}
}
if !opt.AutoRetry {
break RetryLoop
}
switch pErr.TransactionRestart {
case roachpb.TransactionRestart_IMMEDIATE:
r.Reset()
case roachpb.TransactionRestart_BACKOFF:
default:
break RetryLoop
}
if log.V(2) {
log.Infof("automatically retrying transaction: %s because of error: %s",
txn.DebugName(), pErr)
}
}
if pErr != nil {
pErr.StripErrorTransaction()
}
return pErr
}