Why doesn't Quora use PostgreSQL

Post by rimantas » Mon, Jul 26, 2010, 1:52 PM UTC

pilif wrote: post #50

rimantas wrote: post #43

Earlier quoted context omitted.

I'm glad I migrated that huge application from MySQL to Postgres back in 2000. I'm glad I did not touch MySQL for serious stuff ever since then. You should refrain from commenting on MySQL then. It's amazing (and sad) how many pro-PG-anti-MySQL folks don't even know basic things about MySQL but feel entitled to rant and call it "toy DB", "not real RDBMS", etc.

note the emphasis on "serious stuff". I did in fact touch MySQL since then in the process of setting up various open source applications that require MySQL. While back then, I needed Postgres for some features MySQL didn't have but otherwise didn't really dislike MySQL, over those 10 years, I really learned to hate MySQL: - try (erroneously) adding or inserting latin1-data into a UTF-8 table. You'd expect an error me…

  - try (erroneously) adding or inserting latin1-data into a UTF-8
  table. You'd expect an error message, but instead your data gets
  truncated at the first byte with the high bit set. 

  - "alter table sometable add somcolumn integer not null"
  will gladly add the column and place null values in each
  row. Null values that should absolutely not be there. No
  error. No warning.

  Same goes for date columns, but there it's even better as it'll
  set the date to 0000-00-00 which is invalid if you try to add this
  in an insert or update.

  mysql> alter table t1 add column (dob date not null);
  ERROR 1292 (22007): Incorrect date value: '0000-00-00' for
  column 'dob' at row 1

  - I said "corrupt table" earlier. Yeah. That happens with
  MySQL, whereas it never ever (with the exception of faulty
  hardware of  course) happens with any other RDBMS - including
  PostgreSQL.

Post by pilif » Mon, Jul 26, 2010, 2:24 PM UTC

rimantas wrote: post #61

pilif wrote: post #50

Earlier quoted context omitted.

note the emphasis on "serious stuff". I did in fact touch MySQL since then in the process of setting up various open source applications that require MySQL. While back then, I needed Postgres for some features MySQL didn't have but otherwise didn't really dislike MySQL, over those 10 years, I really learned to hate MySQL: - try (erroneously) adding or inserting latin1-data into a UTF-8 table. You'd expect an error me…

So basically you learned to hate MySQL while not doing anything serious with it. Interesting. - try (erroneously) adding or inserting latin1-data into a UTF-8 table. You'd expect an error message, but instead your data gets truncated at the first byte with the high bit set. False. - "alter table sometable add somcolumn integer not null" will gladly add the column and place null values in each row. Null values that sh…

          - try (erroneously) adding or inserting latin1-data into a UTF-8
          table. You'd expect an error message, but instead your data gets
          truncated at the first byte with the high bit set. 

    False.

        - "alter table sometable add somcolumn integer not null"
        will gladly add the column and place null values in each
        row. Null values that should absolutely not be there. No
        error. No warning.

    False.

    mysql> alter table foo add dob date not null;
    Query OK, 0 rows affected (0.00 sec)
    Records: 0  Duplicates: 0  Warnings: 0

    mysql> describe foo;
    +----------+-------------+------+-----+---------+----------------+
    | Field    | Type        | Null | Key | Default | Extra          |
    +----------+-------------+------+-----+---------+----------------+
    | id       | int(11)     | NO   | PRI | NULL    | auto_increment | 
    | value    | varchar(10) | NO   |     |         |                | 
    | intvalue | int(11)     | NO   |     | NULL    |                | 
    | dob      | date        | NO   |     | NULL    |                | 
    +----------+-------------+------+-----+---------+----------------+
    4 rows in set (0.01 sec)

    mysql> 

Post by jeltz » Mon, Jul 26, 2010, 2:46 PM UTC

blueberry wrote: post #38

Those who commented in favor of postgres: What are some of the biggest deployments of postgres? Facebook has a gargantic deployment of MySQL and it just works. The author of the answer on Quora mentions reliable scalability as the most important factor for their MySQL choice on another answer here: http://bit.ly/dm6HtQ . What is the biggest system that postgres is deployed in?

Post by Daishiman » Mon, Jul 26, 2010, 7:03 PM UTC

rimantas wrote: post #64

pilif wrote: post #63

Earlier quoted context omitted.

- try (erroneously) adding or inserting latin1-data into a UTF-8 table. You'd expect an error message, but instead your data gets truncated at the first byte with the high bit set. False. http://www.gnegg.ch/2008/02/failing-silently-is-bad/ - "alter table sometable add somcolumn integer not null" will gladly add the column and place null values in each row. Null values that should absolutely not be there. No error. N…

Maybe you just don't know what you are doing.

Post by shazow » Mon, Jul 26, 2010, 7:57 PM UTC

jeltz wrote: post #65

blueberry wrote: post #38

Those who commented in favor of postgres: What are some of the biggest deployments of postgres? Facebook has a gargantic deployment of MySQL and it just works. The author of the answer on Quora mentions reliable scalability as the most important factor for their MySQL choice on another answer here: http://bit.ly/dm6HtQ . What is the biggest system that postgres is deployed in?

Some examples: Skype uses PostgreSQL for their VOIP services. Yahoo! has a customized PostgeSQL for their data warehousing storing a couple of petabytes of data. I believe IMDB is another quite prominent user.