Two words that instill fear in any database developer: Cartesian Join.

I didn’t realize what was happening until the DBA paid me a personal visit asking what I was running that had cached over a billion rows.

  • 1
    two tables with over 110000 (accumulated) rows? ouch.
  • 0
    @stop Millions of records, actually.
  • 2
    @TheOracle It happens. Explain / Analysis of query execution can help ;)

    Dunno how often I had these nice long SQL queries with tons of statements...

    And needed to JOIN a table to resolve a poorly performing subselect and overlooked an associative table....

    And suddenly I got tribble data.... Dataset just exploded and the server got very unhappy.

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