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/*
* Copyright 2017 Dgraph Labs, Inc. and Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package badger
// OpenManaged returns a new DB, which allows more control over setting
// transaction timestamps, aka managed mode.
//
// This is only useful for databases built on top of Badger (like Dgraph), and
// can be ignored by most users.
func OpenManaged(opts Options) (*DB, error) {
opts.managedTxns = true
return Open(opts)
}
// NewTransactionAt follows the same logic as DB.NewTransaction(), but uses the
// provided read timestamp.
//
// This is only useful for databases built on top of Badger (like Dgraph), and
// can be ignored by most users.
func (db *DB) NewTransactionAt(readTs uint64, update bool) *Txn {
if !db.opt.managedTxns {
panic("Cannot use NewTransactionAt with managedDB=false. Use NewTransaction instead.")
}
txn := db.newTransaction(update, true)
txn.readTs = readTs
return txn
}
// NewWriteBatchAt is similar to NewWriteBatch but it allows user to set the commit timestamp.
// NewWriteBatchAt is supposed to be used only in the managed mode.
func (db *DB) NewWriteBatchAt(commitTs uint64) *WriteBatch {
if !db.opt.managedTxns {
panic("cannot use NewWriteBatchAt with managedDB=false. Use NewWriteBatch instead")
}
wb := db.newWriteBatch(true)
wb.commitTs = commitTs
wb.txn.commitTs = commitTs
return wb
}
func (db *DB) NewManagedWriteBatch() *WriteBatch {
if !db.opt.managedTxns {
panic("cannot use NewManagedWriteBatch with managedDB=false. Use NewWriteBatch instead")
}
wb := db.newWriteBatch(true)
return wb
}
// CommitAt commits the transaction, following the same logic as Commit(), but
// at the given commit timestamp. This will panic if not used with managed transactions.
//
// This is only useful for databases built on top of Badger (like Dgraph), and
// can be ignored by most users.
func (txn *Txn) CommitAt(commitTs uint64, callback func(error)) error {
if !txn.db.opt.managedTxns {
panic("Cannot use CommitAt with managedDB=false. Use Commit instead.")
}
txn.commitTs = commitTs
if callback == nil {
return txn.Commit()
}
txn.CommitWith(callback)
return nil
}
// SetDiscardTs sets a timestamp at or below which, any invalid or deleted
// versions can be discarded from the LSM tree, and thence from the value log to
// reclaim disk space. Can only be used with managed transactions.
func (db *DB) SetDiscardTs(ts uint64) {
if !db.opt.managedTxns {
panic("Cannot use SetDiscardTs with managedDB=false.")
}
db.orc.setDiscardTs(ts)
}
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