Calibre 6.23.0 download the last version for ios

Speed improvements of middle-level compression for specific scenarios This speed improvement comes at a slight regression in compression ratio, and is therefore enabled only on non-ultra compression strategies. It wildly accelerates -patch-from compression, typically doubling speed on large files (~1GB), sometimes even more depending on exact scenario. It can also be manually enabled/disabled using -mmap-dict or -no-mmap-dict respectively.Īdditionally, introduces significant speed improvements for -patch-from.Īn I/O optimization in #3486 greatly improves -patch-from decompression speed on Linux, typically by +50% on large files (~1GB).Ĭompression speed is also taken care of, with a dictionary-indexing speed optimization introduced in #3545. This feature is automatically enabled for -patch-from compression/decompression when the dictionary is larger than the user-set memory limit. It's mostly visible under memory pressure, since mmap will be able to release less-used memory and continue working.īut even when memory is plentiful, there are still measurable memory benefits, as shown in the graph below, especially when the reference turns out to be not completely relevant for the patch. This can make a pretty big difference for memory-constrained environments operating patches for large data sets.

This feature allows zstd to memory-map large dictionaries, rather than requiring to load them into memory.

V1.5.5 introduces memory-mapped dictionaries, by for both posix #3486 and windows #3557. Improved memory usage and speed for the -patch-from mode When the issue was detected, there were a number of other improvements and minor fixes already in the making, hence they are also present in this release. While the probability might be very small, corruption issues are nonetheless very serious, so an update to this version is highly recommended, especially if you employ high compression modes (levels 16+). Nevertheless, from Google shepherds such a humongous amount of data that he managed to detect a reproduction case (corruptions are detected thanks to the checksum), making it possible for to investigate and fix the bug. It evaded months of continuous fuzzer tests, due to the number and complexity of simultaneous conditions required to trigger it. The probability to generate such a scenario by random chance is extremely low. The primary focus is to correct a rare corruption bug in high compression mode, detected by.

Calibre 6.23.0 download the last version for ios