Method iterateMetadataFiles

src/Databases/DatabaseOnDisk.cpp:657–750

}

void DatabaseOnDisk::iterateMetadataFiles(const IteratingFunction & process_metadata_file) const
{
    auto db_disk = getDisk();
    if (!db_disk->existsDirectory(metadata_path))
        return;

    auto process_tmp_drop_metadata_file = [&](const String & file_name)
    {
        chassert(getUUID() == UUIDHelpers::Nil);
        static const char * tmp_drop_ext = ".sql.tmp_drop";
        const std::string object_name = file_name.substr(0, file_name.size() - strlen(tmp_drop_ext));

        if (db_disk->existsFileOrDirectory(fs::path(data_path) / object_name))
        {
            db_disk->replaceFile(getMetadataPath() + file_name, getMetadataPath() + object_name + ".sql");
            LOG_WARNING(log, "Object {} was not dropped previously and will be restored", backQuote(object_name));
            process_metadata_file(object_name + ".sql");
        }
        else
        {
            LOG_INFO(log, "Removing file {}", getMetadataPath() + file_name);
            db_disk->removeFileIfExists(getMetadataPath() + file_name);
        }
    };

    /// Metadata files to load: name and flag for .tmp_drop files
    std::vector<std::pair<String, bool>> metadata_files;

    for (const auto it = db_disk->iterateDirectory(metadata_path); it->isValid(); it->next())
    {
        auto sub_path = fs::path(it->path());
        String file_name = it->name();
        /// For '.svn', '.gitignore' directory and similar.
        if (!file_name.empty() && file_name.at(0) == '.')
            continue;

        /// There are .sql.bak files - skip them.
        if (endsWith(file_name, ".sql.bak"))
            continue;

        /// Permanently detached table flag
        if (endsWith(file_name, ".sql.detached"))
            continue;

        if (endsWith(file_name, ".sql.tmp_drop"))
        {
            /// There are files that we tried to delete previously
            metadata_files.emplace_back(file_name, false);
        }
        else if (endsWith(file_name, ".tmp_move_from") || endsWith(file_name, ".tmp_move_to"))
        {
            /// There are temp files generated in MetadataStorageFromPlainObjectStorageMoveFileOperation
            LOG_INFO(log, "Removing file {}", sub_path.string());
            db_disk->removeFileIfExists(sub_path);
        }
        else if (endsWith(file_name, ".sql.tmp"))
        {
            /// There are files .sql.tmp - delete