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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/db/pipeline/document_source_out_replace_coll.h"
namespace mongo {
static AtomicWord<unsigned> aggOutCounter;
void DocumentSourceOutReplaceColl::initializeWriteNs() {
LocalReadConcernBlock readLocal(pExpCtx->opCtx);
DBClientBase* conn = pExpCtx->mongoProcessInterface->directClient();
const auto& outputNs = getOutputNs();
_tempNs = NamespaceString(str::stream() << outputNs.db() << ".tmp.agg_out."
<< aggOutCounter.addAndFetch(1));
// Save the original collection options and index specs so we can check they didn't change
// during computation.
_originalOutOptions = pExpCtx->mongoProcessInterface->getCollectionOptions(outputNs);
_originalIndexes = conn->getIndexSpecs(outputNs.ns());
// Check if it's capped to make sure we have a chance of succeeding before we do all the work.
// If the collection becomes capped during processing, the collection options will have changed,
// and the $out will fail.
uassert(17152,
str::stream() << "namespace '" << outputNs.ns()
<< "' is capped so it can't be used for $out",
_originalOutOptions["capped"].eoo());
// We will write all results into a temporary collection, then rename the temporary
// collection to be the target collection once we are done.
_tempNs = NamespaceString(str::stream() << outputNs.db() << ".tmp.agg_out."
<< aggOutCounter.addAndFetch(1));
// Create temp collection, copying options from the existing output collection if any.
{
BSONObjBuilder cmd;
cmd << "create" << _tempNs.coll();
cmd << "temp" << true;
cmd.appendElementsUnique(_originalOutOptions);
BSONObj info;
uassert(16994,
str::stream() << "failed to create temporary $out collection '" << _tempNs.ns()
<< "': "
<< getStatusFromCommandResult(info).reason(),
conn->runCommand(outputNs.db().toString(), cmd.done(), info));
}
if (_originalIndexes.empty()) {
return;
}
// Copy the indexes of the output collection to the temp collection.
std::vector<BSONObj> tempNsIndexes;
for (const auto& indexSpec : _originalIndexes) {
// Replace the spec's 'ns' field value, which is the original collection, with the temp
// collection.
tempNsIndexes.push_back(indexSpec.addField(BSON("ns" << _tempNs.ns()).firstElement()));
}
try {
conn->createIndexes(_tempNs.ns(), tempNsIndexes);
} catch (DBException& ex) {
ex.addContext("Copying indexes for $out failed");
throw;
}
};
void DocumentSourceOutReplaceColl::finalize() {
LocalReadConcernBlock readLocal(pExpCtx->opCtx);
const auto& outputNs = getOutputNs();
auto renameCommandObj =
BSON("renameCollection" << _tempNs.ns() << "to" << outputNs.ns() << "dropTarget" << true);
pExpCtx->mongoProcessInterface->renameIfOptionsAndIndexesHaveNotChanged(
pExpCtx->opCtx, renameCommandObj, outputNs, _originalOutOptions, _originalIndexes);
};
} // namespace mongo
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