3/6 River Straight - Raise or not?

[chucksim]

Another checkup from the weekend. Live 3/6. Only here 2 orbits, but looks like a typical loose passive table. Most want to see the flop, and won't raise without the goods.

2 folds to a raiser. MP calls, button calls, I look down at

Q [img]/images/graemlins/club.gif[/img] 9 [img]/images/graemlins/club.gif[/img] and I call. (8 SB)

Flop: 7 [img]/images/graemlins/spade.gif[/img] 8 [img]/images/graemlins/diamond.gif[/img] 10 [img]/images/graemlins/spade.gif[/img]

I check, PF Raiser bets, MP folds, button calls, I call. (5.5 BB)

Turn 2 [img]/images/graemlins/club.gif[/img]

I check, PF Raiser bets, button calls, I call. (8.5 SB)

River 6 [img]/images/graemlins/spade.gif[/img]

I check, PFR bets, button calls, I raise (????)

Now, is the river raise just spewing, or standard? I had the odds to chase, and I got there, but so did the flush.

I read PFR for a big pair or a big A, and he obviously didn't like the river and made a little whince when it hit.

I figured button would have raised if he made his flush instead of trying for an overcall (just didn't think he was that sophisticated). Likewise, he would have raised earlier if he had a higher straight.

Can I trust reads like this at 3/6, or just be safe, call, and hope to take a nice pot?

Also, anyone find a raise anywhere else? Flop, maybe?