Tag: compress

Is it safe to use the Windows “Compress directory to save space” feature on the directory that contains my MySQL general log file?

I have changed MySQL 8 on my Windows 10 development machine to write logfiles (general log and slow queries log) to "E:\mysql logfiles". I’d like to compress this directory using the Windows "Compress Directory to save space" advanced feature in the Windows 10 directory properties to save space (currently my logfile is over 50 GB). I’m wondering though: is this a good idea? Or will this break MySQL in (subtle or not) ways?

Compress JSON String Stored in PostgreSQL, such as MessagePack?

JSON strings are currently being stored in a PostgreSQL 11 table in a text field. For example, a row can have the text field asks containing the string:

{"0.000295":1544.2,"0.000324":1050,"0.000325":40.1,"0.000348":0}

Question: Is it possible to store it in a format that consumes lesser space? Using some CPU cycles to serialize/deserialize the JSON string is acceptable as a compromise for using lesser storage space. The JSON data does not need to be searchable. The JSON object keys are almost always different in different rows.

I am particularly interested in using JSON encoding/compression algorithms like MessagePack with zlib, but how can we use this when inserting the record into the PostgreSQL table?

Note: Also using Node.js with Knex.js to communicate with PostgreSQL. Currently converting JSON objects to strings using Node’s JSON.stringify function.

Is there an algorithm to compress a string array represented as pointers to a long string to pointers with a compressed version of the long string?

In a program I am writing, I represent an array of strings as a long string and have pointers point at the various substrings to present my array. E.g.

str_array = struc string_array    long_str = "abcdefab"    pointer_array = [(start = 0, len = 3), (start = 3, len = 3), (start = 6, len=2)) end

So str_array = ["abc", "def", "ab"], but notice that I can actually compress the long string so by getting rid of “ab” at the end. E.g.

str_array2 = struc string_array    long_str = "abcdef"    pointer_array = [(start = 0, len = 3), (start = 3, len = 3), (start = 0, len=2)) end

and note that str_array2 is also ["abc", "def", "ab"] === str_array.

What’s this type of compresssion callled in computer science? I assume there’s already literature on this type of algorithms?

Batch Compress Videos with ffmpeg

I have many videos in a folder, and I want to compress them all with one command.

To compress one video I use:

sudo apt-get install ffmpeg ffmpeg -i input.mp4 output.mp4

But what if I have many videos I want to compress? I’ve tried the following:

ffmpeg -i ./videos ./compressed-videos

But then I get this error:

./videos: Is a directory

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Receive Access Denied When Attempting to Compress Directory

  • OS Name: Windows 10 Pro
  • OS Version: 10.0.17763 Build 17763

Here’s what I’m doing…

  1. Reboot laptop.
  2. Login.
  3. Open folder “try” on desktop.
  4. Right click on folder “esb”.
  5. Select “Compressed (zipped) folder” from the “Send to” sub-menu.

This is what I get…

enter image description here

I own the folder I’m compressing. I own the directory the folder I’m compressing is in. Why am I getting an access denied message?

This operation works fine if I use 7z or Compress-Archive.