I tried to setup hylafax today. I had it going a few years ago. I even had a neat hack where I would have it take all inbound faxes, convert them into pdf and store them in directory accessible from the web. It was pretty cool. I figured I’d re-create that and maybe add some Python-Fu to have an outbound directory but alas it wasn’t meant to be. I ran around in circles for three hours trying to eliminate the problems but got no-where until I installed efax and right off the bat the fax just worked. That eliminated the problems of (The modem broke between last time and now, the modem doesn’t like the VoIP line, and my new HP A-I-O doesn’t like the fax modem) leaving Hylafax is misconfigured. Here we go again, another mailing list……
More stuff about Postgresql that should be obvious.
I’ve been scratching my head on this one for far too long. I have a query under Postgresql which retrieves the distance between too points given the knowledge of their zipcodes. This work because I have an incomplete table of mileages between arbitrary three digit zipcode pairs. Each time I use this table my queries take a long time and I could never understand why. It has to do with the type that postgresql assigns to computed text fields. I was doing something like this:
SELECT * FROM worklist INNER JOIN partial_zipcode_mileage ON SUBSTRING(worklist.origin_zipcode, 1, 3) = partial_zipcode_mileage.origin_partial_zipcode...
The issue here is the type of the expression: SUBSTRING(worklist.origin_zipcode, 1, 3) as compared to the type of the field partial_zipcode_mileage.origin_partial_zipcode. The latter is a SQL CHAR(3) since it will always hold 3 characters. Postgresql assignes the first expression a type of TEXT since it has know way to know how bit a field you actually want. This prevents the postgresql engine from using the index and this, my query takes along time. Substitute SUBSTRING(worklist.origin_zipcode, 1, 3)::char(3) in the statement and all is happy.
Why math is important.
While I was sleeping we seemed to forget how to do math. This guy was quoted a rate of 0.002 cents per KB to use his Verizon Wireless Data Card while roaming in Canada. When he got the bill they charged him 0.002 dollars/KB. His story is here. What makes it sad is that the verizon customer service people don’t understand the difference and continue to quote him the lower rate while insisting that the charge on the bill is correct. All of this would be a non-issue if the marketing weasels at Verizon would just fess up to the fact that their price for roaming data is $2.05 / MB.