Data Cache

Data caching functionality for MDA files.

This module provides caching capabilities to improve performance when loading and processing MDA files.

DataCache(*args, **kwargs)	LRU cache for MDA file data to improve performance and manage memory usage.
CachedFileData(file_path, metadata, ...)	Cached file data with metadata.
get_global_cache()	Get the global data cache instance.

class mdaviz.data_cache.CachedFileData(file_path: str, metadata: dict[str, ~typing.Any], scan_dict: dict[str, ~typing.Any], first_pos: int, first_det: int, pv_list: list, file_name: str, folder_path: str, access_time: float = <factory>, size_bytes: int = 0)

Cached file data with metadata.

get_size_mb() → float

Get the size in megabytes.

update_access_time() → None

Update the last access time.

class mdaviz.data_cache.DataCache(*args: Any, **kwargs: Any)

LRU cache for MDA file data to improve performance and manage memory usage.

This cache stores loaded MDA file data in memory and automatically evicts least recently used entries when memory limits are exceeded.

Attributes:

max_size_mb (float): Maximum cache size in megabytes max_entries (int): Maximum number of cached entries enable_compression (bool): Whether to compress cached data max_memory_mb (float): Maximum system memory usage in megabytes

_check_memory_usage() → float

Check current memory usage and trigger cleanup if needed.

Returns:

float: Current memory usage in MB

_evict_lru() → bool

Evict the least recently used entry from the cache.

Returns:

bool: True if an entry was evicted, False if cache is empty

_load_without_caching(path_obj: Path) → CachedFileData | None

Load file data without caching it (for large files or high memory usage).

Parameters:

path_obj (Path): Path object to the file

Returns:

CachedFileData or None: Loaded data (not cached)

_perform_memory_cleanup() → None

Perform aggressive memory cleanup when usage is high.

cache_eviction

alias of str

cache_hit

alias of str

cache_miss

alias of str

clear() → None

Clear all cached data.

get(file_path: str) → CachedFileData | None

Get cached data for a file.

Parameters:

file_path (str): Path to the file

Returns:

CachedFileData or None: Cached data if available, None otherwise

get_or_load(file_path: str) → CachedFileData | None

Get cached data or load and cache it if not available.

Parameters:

file_path (str): Path to the file

Returns:

CachedFileData or None: Data from cache or newly loaded

get_stats() → dict[str, Any]

Get cache statistics.

Returns:

dict: Cache statistics including size, entry count, hit rate, etc.

load_and_cache(file_path: str) → CachedFileData | None

Load file data and cache it.

Parameters:

file_path (str): Path to the file to load

Returns:

CachedFileData or None: Loaded and cached data

memory_warning

alias of float

put(file_path: str, cached_data: CachedFileData) → None

Store data in the cache.

Parameters:

file_path (str): Path to the file cached_data (CachedFileData): Data to cache

remove(file_path: str) → bool

Remove a file from the cache.

Parameters:

file_path (str): Path to the file to remove

Returns:

bool: True if the file was in the cache, False otherwise

set_max_entries(max_entries: int) → None

Set the maximum number of cache entries.

Parameters:

max_entries (int): New maximum number of entries

set_max_size_mb(max_size_mb: float) → None

Set the maximum cache size.

Parameters:

max_size_mb (float): New maximum size in megabytes

mdaviz.data_cache.get_global_cache() → DataCache

Get the global data cache instance.

Returns:

DataCache: Global cache instance

mdaviz.data_cache.set_global_cache(cache: DataCache) → None

Set the global data cache instance.

Parameters:

cache (DataCache): Cache instance to use globally