a36753cf27
Summary: Snapshots should have the transaction from which they were created because we need this info for recovery later on. Otherwise we wouldn't be able to tell the workers from which snapshots to recover. The whole cluster should be recovered from the same transaction snapshot. Reviewers: msantl Reviewed By: msantl Subscribers: pullbot Differential Revision: https://phabricator.memgraph.io/D1338
98 lines
3.8 KiB
C++
98 lines
3.8 KiB
C++
#include "durability/paths.hpp"
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#include <experimental/filesystem>
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#include <experimental/optional>
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#include <string>
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#include "glog/logging.h"
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#include "transactions/type.hpp"
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#include "utils/datetime/timestamp.hpp"
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#include "utils/string.hpp"
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namespace durability {
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namespace fs = std::experimental::filesystem;
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/// Returns true if the given directory path exists or is succesfully created.
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bool EnsureDir(const fs::path &dir) {
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if (fs::exists(dir)) return true;
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std::error_code error_code; // Just for exception suppression.
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return fs::create_directories(dir, error_code);
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}
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/// Ensures the given durability directory exists and is ready for use. Creates
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/// the directory if it doesn't exist.
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void CheckDurabilityDir(const std::string &durability_dir) {
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namespace fs = std::experimental::filesystem;
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if (fs::exists(durability_dir)) {
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CHECK(fs::is_directory(durability_dir))
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<< "The durability directory path '" << durability_dir
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<< "' is not a directory!";
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} else {
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bool success = EnsureDir(durability_dir);
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CHECK(success) << "Failed to create durability directory '"
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<< durability_dir << "'.";
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}
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}
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/// Returns the transaction id contained in the file name. If the filename is
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/// not a parseable WAL file name, nullopt is returned. If the filename
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/// represents the "current" WAL file, then the maximum possible transaction ID
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/// is returned because that's appropriate for the recovery logic (the current
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/// WAL does not yet have a maximum transaction ID and can't be discarded by
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/// the recovery regardless of the snapshot from which the transaction starts).
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std::experimental::optional<tx::transaction_id_t> TransactionIdFromWalFilename(
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const std::string &name) {
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auto nullopt = std::experimental::nullopt;
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// Get the max_transaction_id from the file name that has format
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// "XXXXX__max_transaction_<MAX_TRANS_ID>_worker_<Worker_ID>"
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auto file_name_split = utils::RSplit(name, "__", 1);
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if (file_name_split.size() != 2) {
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LOG(WARNING) << "Unable to parse WAL file name: " << name;
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return nullopt;
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}
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if (utils::StartsWith(file_name_split[1], "current"))
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return std::numeric_limits<tx::transaction_id_t>::max();
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file_name_split = utils::Split(file_name_split[1], "_");
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if (file_name_split.size() != 5) {
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LOG(WARNING) << "Unable to parse WAL file name: " << name;
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return nullopt;
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}
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auto &tx_id_str = file_name_split[2];
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try {
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return std::stoll(tx_id_str);
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} catch (std::invalid_argument &) {
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LOG(WARNING) << "Unable to parse WAL file name tx ID: " << tx_id_str;
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return nullopt;
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} catch (std::out_of_range &) {
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LOG(WARNING) << "WAL file name tx ID too large: " << tx_id_str;
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return nullopt;
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}
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}
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fs::path MakeSnapshotPath(const fs::path &durability_dir, const int worker_id,
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tx::transaction_id_t tx_id) {
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std::string date_str =
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Timestamp(Timestamp::Now())
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.ToString("{:04d}_{:02d}_{:02d}__{:02d}_{:02d}_{:02d}_{:05d}");
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auto file_name = date_str + "_worker_" + std::to_string(worker_id) + "_tx_" +
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std::to_string(tx_id);
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return durability_dir / kSnapshotDir / file_name;
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}
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/// Generates a file path for a write-ahead log file. If given a transaction ID
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/// the file name will contain it. Otherwise the file path is for the "current"
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/// WAL file for which the max tx id is still unknown.
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fs::path WalFilenameForTransactionId(
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const std::experimental::filesystem::path &wal_dir, int worker_id,
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std::experimental::optional<tx::transaction_id_t> tx_id) {
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auto file_name = Timestamp::Now().ToIso8601();
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if (tx_id) {
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file_name += "__max_transaction_" + std::to_string(*tx_id);
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} else {
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file_name += "__current";
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}
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file_name = file_name + "_Worker_" + std::to_string(worker_id);
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return wal_dir / file_name;
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}
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} // namespace durability
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