Sqlite inserts inside a PDO fetch loop

Hello,

I have a situation where I am trying to create an index of words  
contained in a particular table.  The table is about 9,400 rows, and  
the index ends up being 1,500,000 words (rows).  While creating the  
index, I do a select of the table, and extract the words.  I cache  
these word results into an array, and use that array for a prepared  
insert statement into the word index table.

My problem is memory.  It maxes out at about 35 MB.  This is a bit  
high, and what I would like to do is do an onset transaction when the  
array reaches a certain size, like 10,000, then unset the array and  
continue.  The problem with that is I cannot commit the insert while  
the fetch statement is still pending.

I have tried fetchAll instead, but still have similar memory issues.

I have also tried to commit the inserts at the end, but that causes  
Sqlite to hog the memory.

Is there any way to fix this, or is this just the cost of doing  
business with Sqlite?

Thanks!

B