Petr, could you please elaborate more on this last claim? If turning the dump generation into an incremental process is the task you are interested in solving, then I don't understand how text constitutes a problem. Text files can be appended to as any regular file and it shouldn't be difficult to do this in a way that preserves the XML structure valid.

As I said, having the possibility to seek and inspect the files manually is a tremendous boon when debugging your code. With what you propose that would be possible but more complicate, since one cannot seek at a specific position of stdout without going through the whole contents.



On Jul 3, 2013 4:05 PM, "Petr Onderka" <> wrote:
A reply to all those who basically want to keep the current XML dumps:

I have decided to change the primary way of reading the dumps: it will now be a command line application that outputs the data as uncompressed XML, in the same format as current dumps.

This way, you should be able to use the new dumps with minimal changes to your code.

Keeping the dumps in a text-based format doesn't make sense, because that can't be updated efficiently, which is the whole reason for the new dumps.

Petr Onderka

On Mon, Jul 1, 2013 at 11:10 PM, Byrial Jensen <> wrote:

As a regular of user of dump files I would not want a "fancy" file format with indexes stored as trees etc.

I parse all the dump files (both for SQL tables and the XML files) with a one pass parser which inserts the data I want (which sometimes is only a small fraction of the total amount of data in the file) into my local database. I will normally never store uncompressed dump files, but pipe the uncompressed data directly from bunzip or gunzip to my parser to save disk space. Therefore it is important to me that the format is simple enough for a one pass parser.

I cannot really imagine who would use a library with object oriented API to read dump files. No matter what it would be inefficient and have fewer features and possibilities than using a real database.

I could live with a binary format, but I have doubts if it is a good idea. It will be harder to take sure that your parser is working correctly, and you have to consider things like endianness, size of integers, format of floats etc. which give no problems in text formats. The binary files may be smaller uncompressed (which I don't store anyway) but not necessary when compressed, as the compression will do better on text files.

- Byrial

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