What does double "at" (@) marks mean in this SQL query?

I couldn't find anything about this in MySQL documentation.

SELECT accesion_id, 
       definition 
  FROM accesion_table 
 WHERE search_word @@ ? 开发者_运维问答OFFSET ? LIMIT Const.MAX_DISP_COUNT;

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Most likely the code that is executing this sql statement has some parser that's handling this odd syntax, since the the @@, ? and Const.MAX_DISPLAY_COUNT aren't part of MySQL. Also the keyword OFFSET must be placed after the LIMIT keyword.

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With Oracle the '@@' to point to the current directory of the executing file. Could it be that MySql might be following Oracles lead?