If LZO compressed file is used as input then the input format has to be LzoTextInputFormat in the wordcount MapReduce program, so following change is required in the job configuration of the MapReduce job. You can see from the console message that only single split is created as the file is not indexed.
In order to make LZO file splittable you will have to run indexer as a preprocessing step. You can run lzo indexer as a Java program or as a MapReduce job. If you have any doubt or any suggestions to make please drop a comment. Table of contents. Posted by Anshudeep. Labels: Hadoop , Hadoop-IO. With --quiet, the title and totals lines are not displayed. List each compressed file in a format similar to ls -ln.
G Inhibit display of group information. Q Enclose file names in double quotes. Write output on standard output. If there are several input files, the output consists of a sequence of independently de compressed members. To obtain better compression, concatenate all input files before compressing them. Write output to the file FILE.
Write output files into the directory DIR instead of the directory determined by the input file. If DIR is omitted, then write to the current working directory. Do not store or verify a checksum of the uncompressed file when compressing or decompressing. This speeds up the operation of lzop a little bit especially when decompressing , but as unnoticed data corruption can happen in case of damaged compressed files the usage of this option is not generally recommended.
Also, a checksum is always stored when compressing with one of the slow compression levels -7, -8 or -9 , regardless of this option. When decompressing, do not restore the original file name if present remove only the lzop suffix from the compressed file name. This option is the default under UNIX. When decompressing, restore the original file name if present. This option is useful on systems which have a limit on file name length. If the original name saved in the compressed file is not suitable for its file system, a new name is constructed from the original one to make it legal.
When decompressing, restore the original path and file name if present. When compressing, store the relative and cleaned path name. This option is mainly useful when using archive mode - see usage examples below.
Everyone wants fast applications. Recently, we provided a mechanism to make snap applications launch faster by using the LZO format. We introduced this change because users reported desktop snaps starting more slowly than the same applications distributed via traditional, native Linux packaging formats like Deb or RPM.
After a thorough investigation, we pinpointed the compression method as the primary slowdown. Here, we want to take you through the journey of understanding why we picked LZO, and what is next for the snap compression story. Previously, the only supported compression format for snaps was XZ. This decision was borne out of two main determining factors: compatibility and size.
One of the primary delivery targets for snaps in addition to desktop users is IoT devices, and so for those, we wanted to have the smallest possible size. Additionally, cross-distro support is very important with snaps, and so we also wanted to make sure that the compression format chosen would be compatible with the widest range of kernels.
In both cases, the XZ method fit the bill nicely. Additionally, at the time the decision was made, some of the new algorithms such as ZSTD were not even in existence. The first thing is the choice of squashfs as the packaging mechanism — instead of distributing individual files as tarballs, etc.
We wanted both determinism and ease of deployment whereby all users of a snap get the same files, and those files are not modifiable by the user. To satisfy both goals, we selected squashfs, which is a compressed filesystem format that is mounted read-only. Orthogonal to that goal was package integrity. It was crucial to have a design where the files that were delivered to users were cryptographically verified, as well.
We wanted a system where the bits that make up the. As such the snap that is uploaded can currently only be uploaded and distributed with a single compression setting. When we started looking into why desktop applications packaged as snaps were slower, we explored multiple hypotheses, and we focused on the difference in startup times between the various packaging formats.
For example, here is a graph created at the start of these explorations, demonstrating how many milliseconds it takes to launch a snap application vs the same application packaged natively:. All launches were performed with as much caching turned off as possible.
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