It really depends on the RDBMS and the type of the table. There is no absolute "this is what happens to space freed by deleted rows". It's something that you need to find out about, preferably before all of your table space is gone and you don't know why.
$h=$ENV{HOME};my@q=split/\n\n/,`cat $h/.quotes`;$s="$h/."
."signature";$t=`cat $s`;print$t,"\n",$q[rand($#q)],"\n";
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