Fix merge bugs due to path error

[ucasfl]

Changelog category (leave one):

• Bug Fix (user-visible misbehavior in an official stable release)

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Fix merge fail with vector index.

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

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[Aed-p]

Hi ucasfl,

Thank you for the PR and for taking the time to address this issue!

To help us understand this fix better, could you please provide a description of the bug, including the specific scenario or conditions that trigger it? Additionally, if you have any test cases to verify the fix, that would be very helpful for ensuring everything works as expected and for preventing similar issues in the future.

Thanks again for your contribution!

[ucasfl]

@Aed-p Use inverted_row_ids_map_file_path as example.

MyScaleDB/src/Storages/MergeTree/MergeTask.cpp

Lines 397 to 398 in 3bd6368

	global_ctx->inverted_row_ids_map_file_path
	= global_ctx->new_data_part->getDataPartStorage().getFullPath() + "merged-inverted_row_ids_map" + VECTOR_INDEX_FILE_SUFFIX;

It include the full path of the disk, and writeFile only need to provede the file name:

MyScaleDB/src/Storages/MergeTree/MergeTask.cpp

Lines 639 to 640 in 3bd6368

	global_ctx->inverted_row_ids_map_uncompressed_buf = global_ctx->new_data_part->getDataPartStorage().writeFile(
	global_ctx->inverted_row_ids_map_file_path, 4096, global_ctx->context->getWriteSettings());

MyScaleDB/src/Storages/MergeTree/DataPartStorageOnDiskFull.cpp

Lines 111 to 121 in 3bd6368

	std::unique_ptr<WriteBufferFromFileBase> DataPartStorageOnDiskFull::writeFile(
	const String & name,
	size_t buf_size,
	WriteMode mode,
	const WriteSettings & settings)
	{
	if (transaction)
	return transaction->writeFile(fs::path(root_path) / part_dir / name, buf_size, mode, settings, /* autocommit = */ false);
	else
	return volume->getDisk()->writeFile(fs::path(root_path) / part_dir / name, buf_size, mode, settings);
	}

So we should use fileName to get the file name when calling writeFile like other places, otherwise, the path pass into Disk become full_disk_path/full_disk_path/filename, leading to file does not exist error due to directory does not exist.

MyScaleDB/src/Storages/MergeTree/MergeTask.cpp

Line 634 in 3bd6368

auto rows_sources_read_buf = std::make_unique<CompressedReadBufferFromFile>(ctx->tmp_disk->readFile(fileName(ctx->rows_sources_file->path())));

MyScaleDB/src/Storages/MergeTree/MergeTask.cpp

Line 298 in 3bd6368

ctx->rows_sources_uncompressed_write_buf = ctx->tmp_disk->writeFile(fileName(ctx->rows_sources_file->path()), DBMS_DEFAULT_BUFFER_SIZE, WriteMode::Rewrite, global_ctx->context->getWriteSettings());