How do I truncate the last/partial fragment of a sentance from a paragraph? (strip all the characters after the last "." in the string)?

I have several million long-text descriptions that I need to truncate to 1000 characters. This often leaves me with a block of text that looks like:

"...one of his best tracks. It's good. His other notew"

I want to identify these fragments and remove the partial sentence or all chars past the last period to get this:

"...one of his best tracks. It's good." 

if Len($lRow) > 1000 {
    $lRow = substr($lRow, 0, 1000);
    $lRow =~ tr/\. xxxx$//;  # here is where I have trouble
}

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I have used "Split" to create an array based on "." chars, then truncated the last member off and re-joined but this adds a 20 fold increase in processing time.

I also know I have to be careful of greedy pattern matching but I am un-sure how to use the non-greedy "+?" regreps.

In reply to Truncating Last Sentence by FatDog

Title:
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