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Title: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: mizerydearia on July 13, 2011, 01:27:27 PM Britcoin (http://britcoin.co.uk/) no longer listed at http://bitcoincharts.com/ and http://bitcoinwatch.com/ because tcatm considers a valid, yet extreme, order "absurd data."
Cost / BTC: 944219654443.157 Giving: 0.00161383 BTC Wanted: 1523810004.93 GBP Quote <wardearia> Hiya. How come http://britcoin.co.uk/ and http://intersango.com/ are not on listed at http://bitcoinwatch.com/? <censored> intersango does not have trades yet and britcoins API is broken <wardearia> How so? <censored> it has a strange orderbook entry (something around 9 billion GBP for 0.0016.. BTC) <wardearia> That means the API is broken? <censored> well not broken, but my backend refuses to parse such absurd data <censored> people have been complaining about the invalid data so I figured it would be best to hide it until it is resolved <wardearia> So then hide the data? Don't delist the exchange? <censored> that's what I did. I clicked "hide" in the backend. <wardearia> The particular data that is related to what your backend cannot handle, not all of the data <censored> the backend doesn't support that <wardearia> Did you write the backend? <censored> yes <censored> the problem is actually pretty simple: the underlying database model is limited to 10 digits and 8 decimals. changing that would require migrating about 8 GB of data <censored> also, other exchanges with similar absurd orders were happy when I reported them so they could fix their exchange <censored> when did I give you permission to cross paste this on the forum anyway? <wardearia> You didn't. Shall I censor your name? <wardearia> I changed it <censored> first, you should not make anything I say in private "official" (like posting it on the forum) <censored> so could you remove that forum post? <wardearia> I made it "unofficial" <wardearia> If there were a zimbabwean dollar exchange, would your site be unable to handle the data? <wardearia> sites* <censored> why? <wardearia> I'm curious <censored> should work fine <censored> if there are problems I can still migrate the database schema <censored> the problem with the order is more like this: if I extended the schema to allow more digits one user might discover that a decimal can have more than hundred digits and place a order for 0.00000001 BTC @ 10000000000000000000000000000000000000000000000000000000000000000 GBP. same problem again <wardearia> Is it possible to ignore such data and continue parsing remaining data? <censored> nope <censored> well, technically yes, but it would break the incremental orderbook feature In case this thread is deleted/censored, there is also http://bitcoin.witcoin.com/p/1859/britcoin-removed-from-bitcoinchartsbitcoinwatch-due-to-absurd-data http://bitcoincharts.com/news/ Quote Britcoin hidden July 13, 2011, 1:41 p.m. Because of data consistency errors britcoinGBP is currently hidden. This will be resolved soon. Title: Re: britcoin removed from bitcoincharts and bitcoinwatch due to "absurd data." Post by: Sultan on July 13, 2011, 01:41:42 PM I noticed this as well, and it was messing up the graph big-time. It must be a bug or something.
Title: Re: britcoin removed from bitcoincharts and bitcoinwatch due to "absurd data." Post by: phantomcircuit on July 13, 2011, 01:51:29 PM I noticed this as well, and it was messing up the graph big-time. It must be a bug or something. There is no bug on the britcoin side, merely someone who has placed an order that is extremely unlikely to ever go through. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: BitcoinPorn on July 13, 2011, 02:06:11 PM So Britcoin needs to fix their feeds is what I gather, and they made the issue public?
I'd not accept the site either and Britcoin needs a new person to represent them, because I would not trust my money with kids, and that was the action of children. If this is the case. Seems like a very odd way to handle business, on a web forum. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: phantomcircuit on July 13, 2011, 02:09:09 PM So Britcoin needs to fix their feeds is what I gather, and they made the issue public? I'd not accept the site either and Britcoin needs a new person to represent them, because I would not trust my money with kids, and that was the action of children. If this is the case. Seems like a very odd way to handle business, on a web forum. Again, there is absolutely nothing wrong with the Britcoin feed. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: mizerydearia on July 13, 2011, 02:10:09 PM So Britcoin needs to fix their feeds is what I gather, and they made the issue public? I maded it public at my own personal efforts because I don't like keeping useful/important informations private. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: BitcoinPorn on July 13, 2011, 02:17:21 PM I maded it public at my own personal efforts because I don't like keeping useful/important informations private. lol, sorry to refer to you in third person, I did not know it was you posting this again, I did not catch that, thought this was someone just reposting this information. I can only say if you are wanting to get on the Bitcoincharts web site, I don't believe this is the right path to do so. I am not fully understanding still, even if not wanting to be private, why that personal conversation or chat was posted, that is going to be a huge trust issue not with those people and however their feed goes down, but with you and posting this shit twice already lol. Not like anything important was in the messages, it is the lack of understanding the motivation behind it is all, and it puts the whole situation in question imo. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: Bigpiggy01 on July 13, 2011, 02:20:59 PM I've used Britcoin multiple times and have found absolutely NOTHING wrong with it ;D
There are several other sites around that have almost as absurd orders on them or have had so in the past. Whoever put that order on there meant it as a joke and it says a lot more about the peeps that have an "issue" with it than it does about the site. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: mizerydearia on July 13, 2011, 07:04:01 PM I attempted to sell 0.00161383 bitcoins for 1523810004.93 XXX currency at different exchanges. Here are my results:
bitcoin7.com Quote place sell order: 0.00161383 btc for 1523810004.93 usd Invalid amount place sell order: 0.01 btc for 1523810004.93 usd Invalid amount place sell order: 0.01 btc for 152381000.49 usd Invalid amount place sell order: 0.01 btc for 15238100.04 usd Invalid amount place sell order: 0.01 btc for 1523810.00 usd Invalid amount place sell order: 0.01 btc for 152381.00 usd Invalid amount place sell order: 0.01 btc for 15238.10 usd Invalid amount place sell order: 0.01 btc for 1523.81 usd Invalid amount place sell order: 0.01 btc for 152.38 usd Invalid amount place sell order: 0.01 btc for 15.23 usd Invalid amount place sell order: 1.00 btc for 1523810004.93 usd SUCCESS bitcoin-central.net Quote place sell order: 0.00161383 btc for 1523810004.93 lrusd Amount must be greater than 1.0 BTC awaiting more funds to resolve bitcoinmarket.com Quote maxlength restricted to 8, so not possible with this site bitmarket.eu Quote awaiting account verification btcchina.com Quote place sell order: 0.00161383 btc for 1523810004.93 cny SUCCESS btcex.com Quote place sell order: 0.00161383 btc for 1523810004.93 usd BTC: Quantity is too small place sell order: 0.01 btc for 1523810004.93 usd SUCCESS cavirtex.com Quote place sell order: 0.00161383 btc for 1523810004.93 cad Your request could not be processed, Amount: Cannot order non positive amount place sell order: 0.01 btc for 1523810004.93 cad SUCCESS exchangebitcoins.com Quote place sell order: 0.00161383 btc for 1523810004.93 usd Order not placed. Quantity must be 0.01 BTC or greater. place sell order: 0.01 btc for 1523810004.93 usd SUCCESS tradehill.com Quote place sell order: 0.00161383 btc for 1523810004.93 usd The smallest allowable BTC amount is currently 0.0100 BTC place sell order: 0.01 btc for 1523810004.93 usd SUCCESS virwox.com Quote place sell order: 0.00161383 btc for 1523810004.93 sll The requested amount is below the minimum amount. You need to exchange at least 1 BTC. place sell order: 1 btc for 1523810004.93 sll SUCCESS Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: enmaku on July 13, 2011, 07:15:06 PM If storage is cheap enough to use decimal/numeric in your database instead of floats then why can't you spend the extra storage to max out that field when you made it in the first place. MySQL allows up to 65 digits in the decimal data type, and MS SQL allows 38. Since these are the two most common database engines you'll encounter in the wild, I'd suggest limiting orders around the least common denominator: decimal(38,8).
I've written a couple personal projects that store BTC and USD values in a database and I assure you every such field is decimal(38,8) - I'd never even consider using anything else. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: tcatm on July 13, 2011, 07:25:28 PM If storage is cheap enough to use decimal/numeric in your database instead of floats then why can't you spend the extra storage to max out that field when you made it in the first place. MySQL allows up to 65 digits in the decimal data type, and MS SQL allows 38. Since these are the two most common database engines you'll encounter in the wild, I'd suggest limiting orders around the least common denominator: decimal(38,8). I've written a couple personal projects that store BTC and USD values in a database and I assure you every such field is decimal(38,8) - I'd never even consider using anything else. If I did that someone will insist that entering an amount with 39 (or 66) digits is a good idea. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: mizerydearia on July 13, 2011, 08:44:57 PM tcatm argued that he delisted Britcoin due to "absurd data."
Now other markets also contain "absurd data" but they are not yet delisted at http://bitcoincharts.com/ or http://bitcoinwatch.com/ both operated by tcatm. btcchina.com https://btcchina.com/trade/depth (must be logged in) http://pastebin.com/raw.php?i=ZWmav7gn (I couldn't find json output) btcex.com https://btcex.com/site/orders/2 http://pastebin.com/MceYWtvn cavirtex.com can't find public data exchangebitcoins.com https://www.exchangebitcoins.com/data/depth http://pastebin.com/3NEmTqeY tradehill.com https://api.tradehill.com/APIv1/USD/Orderbook http://pastebin.com/0NjNfmjQ virwox.com Requires POST to retrieve json data, too much effort Will these sites that contain "absurd data" also be delisted or does tcatm have some sort of personal bias or alterior motives/incentives? Update: Britcoin is relisted at bitcoinwatch.com and bitcoincharts.com. Note: The only winning move is not to play. I losted. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: BitcoinPorn on July 13, 2011, 09:16:31 PM Will these sites that contain "absurd data" also be delisted or does tcatm have some sort of personal bias or alterior motives/incentives? I want to say there is a happy ending here, but every time I read this thread I pull out another wacky theory on what is going on behind the scenes with the exchange sites. It seems you did a lot of work mizerydearia, I hope the Britcoin users appreciate it :)Update: Britcoin is relisted at bitcoinwatch.com and bitcoincharts.com. Note: The only winning move is not to play. I losted. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: weex on July 13, 2011, 09:17:09 PM We at ExchangeBitcoins.com are working on this now and will post an update when it's resolved.
Edit: Resolved. These orders have been canceled, affected users notified, and we have implemented sanity checks to ensure only sensible orders can be placed in our order book. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: mizerydearia on July 13, 2011, 10:03:18 PM We at ExchangeBitcoins.com are working on this now and will post an update when it's resolved. Edit: Resolved. These orders have been canceled, affected users notified, and we have implemented sanity checks to ensure only sensible orders can be placed in our order book. Quote Hello mizerydearia, Today we received some reports of orders with very high prices/quantites that shouldn't have made it into the order book. One of them was on your account and has been cancelled. We have since implemented some sanity checks to be sure only valid orders can be placed. We apologize for any inconvenience. Let us know if you have any questions. Thank you, David Sterry, President ExchB: 1st Bitcoin Exchange in the US email: davids@exchangebitcoins.com cell/text: 650-773-5942 To determine what weex/ExchangeBitcoins considers the current borderline for sanity/insanity in terms of amounts/values, I have done some benchmark testing. Error message for 'insane' is: Order not placed. Price out of range. INSANE Sell 0.00161383 bitcoins for us$1523810004.93 INSANE Sell 0.009 bitcoins for us$1.00/1 bitcoin INSANE Sell 0.009 bitcoins for us$0.01/1 bitcoin SANE Sell 0.01 bitcoins for us$1.00/1 bitcoin I mistook selling 0.01 bitcoins for us$1 as us$1 for 0.01 bitcoins NOT us$1 for 1.0 bitcoin and then my order went through at us$13.968, but I only have us$0.1389, so there is a transaction fee (which I would have noticed if I paid attention) and therefore I will not use this site again (because I refuse to be charged for these types of transactions). Yay for bitomat (http://bitomat.pl/) (which I am unaffiliated with) and a few other exchanges with no transaction fees! Note: I am newbie trader Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: Sultan on July 13, 2011, 10:37:11 PM Nothing is wrong with BritCoin itself, but there must be SOMETHING wrong when it is reporting that a sale was made where somebody paid 10,000 pound for a BitCoin, I am certain that sale never went through or was for a small amount of BitCoins, it shouldn't have even got matched in the first place!
All the erroneous data needs to be cleaned out, when you look at BitCoin Charts and display the last 60 days' activity for BritCoin its all skewered because of this rubbish data! Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: mizerydearia on July 13, 2011, 10:45:36 PM Nothing is wrong with BritCoin itself, but there must be SOMETHING wrong when it is reporting that a sale was made where somebody paid 10,000 pound for a BitCoin, I am certain that sale never went through or was for a small amount of BitCoins, it shouldn't have even got matched in the first place! All the erroneous data needs to be cleaned out, when you look at BitCoin Charts and display the last 60 days' activity for BritCoin its all skewered because of this rubbish data! I think it was an open ask order and not a completed trade. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: FreeMoney on July 13, 2011, 11:07:03 PM No one is entitled to space on bitcoinwatch or any other page. I don't want to see 8 or 10 or 20 digit orders and I appreciate bitcoincharts shielding my innocent eyes from the obscenity.
P.S. if anyone is interested I'm buying coins. 800BTC for .04 cents. Please relay this offer on any relevant websites. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: zebedee on July 13, 2011, 11:10:07 PM Nothing is wrong with BritCoin itself, but there must be SOMETHING wrong when it is reporting that a sale was made where somebody paid 10,000 pound for a BitCoin, I am certain that sale never went through or was for a small amount of BitCoins, it shouldn't have even got matched in the first place! All the erroneous data needs to be cleaned out, when you look at BitCoin Charts and display the last 60 days' activity for BritCoin its all skewered because of this rubbish data! No, they really happen; I had one myself (not at that crazy rate though). Their software is buggy; user beware! Unfortunately if you point out this bug to Britcoin they fob you off. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 14, 2011, 01:09:48 AM Nothing is wrong with BritCoin itself, but there must be SOMETHING wrong when it is reporting that a sale was made where somebody paid 10,000 pound for a BitCoin, I am certain that sale never went through or was for a small amount of BitCoins, it shouldn't have even got matched in the first place! All the erroneous data needs to be cleaned out, when you look at BitCoin Charts and display the last 60 days' activity for BritCoin its all skewered because of this rubbish data! No, they really happen; I had one myself (not at that crazy rate though). Their software is buggy; user beware! Unfortunately if you point out this bug to Britcoin they fob you off. Their software is buggy and I've offered a fix for it several times now. The problem is that decisions are made based on how much you are still wanting, rather than the original price you requested. Genjix has claimed that the 'want' field isn't actually used any more: You're right, we do ignore the want field. It's mostly left for display and is kind of redundant. It's not even needed. but I think he's mistaken. The 'want' field is still used, and is exactly what's causing the problem. Here are some examples that show how very low and very high priced trades happen: This is how very low priced trades happen: User A has 50 GBP and wants 5 BTC (buying BTC at 10 GBP/BTC) User B has 6 BTC and wants 54 GBP (selling BTC at 9 GBP/BTC) User A's order goes in first, and is unmatched. User B's order goes in 2nd, and is partially matched at User A's rate of 10 GBP/BTC. User B gives 5 BTC to user A and gets 50 GBP in exchange. User B now has 1 BTC and the 'wants' value is updated to 4 GBP. User C can now come along and buy User B's remaining 1 BTC for 4 GBP, even though the market price is in the range of 9 or 10 GBP/BTC. Note that overall, User B gets 54 BTC for his 6 BTC, and so actually gets the price he was expecting to. It's just that some was better than expected (5 sold to A for 10 GBP each) and some was much worse than expected (1 sold to C for 4 GBP). This is how very high priced trades happen: User A has 5 BTC and wants 45 GBP (selling 5 BTC at 9 GBP/BTC) User B has 51 GBP and wants 5.1 BTC (buying 5.1 BTC at 10 GBP/BTC) User A's order goes in first, and is unmatched. User B's order goes in 2nd, and is partially matched at User A's rate of 9 GBP/BTC. User B gives 45 GBP to user A and gets 5 BTC in exchange. User B now has 6 GBP and the 'wants' value is updated to 0.1 BTC. User C can now come along and sell 0.1 BTC to User B for 6 GBP, at a price of 60 GBP/BTC even though the market price is in the range of 9 or 10 GBP/BTC. Note that overall, User B gets 5+0.1=5.1 BTC for his 45+6=51 GBP, and so actually gets the price he was expecting to. It's just that some was better than expected (5 bought from A for 9 GBP each) and some was much worse than expected (0.1 bought from C for 60 GBP each). This is why absurdly priced trades show up in the API - it's because they actually happen. My patch to fix this and stop the silly priced trades is here: https://gitorious.org/intersango/intersango/merge_requests/3 Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: phantomcircuit on July 14, 2011, 07:47:59 AM Nothing is wrong with BritCoin itself, but there must be SOMETHING wrong when it is reporting that a sale was made where somebody paid 10,000 pound for a BitCoin, I am certain that sale never went through or was for a small amount of BitCoins, it shouldn't have even got matched in the first place! All the erroneous data needs to be cleaned out, when you look at BitCoin Charts and display the last 60 days' activity for BritCoin its all skewered because of this rubbish data! No, they really happen; I had one myself (not at that crazy rate though). Their software is buggy; user beware! Unfortunately if you point out this bug to Britcoin they fob you off. If you would like to see the order matching for yourself.. just go and look https://gitorious.org/intersango/intersango/blobs/master/cron/process_orders.php Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 14, 2011, 07:52:47 AM If you would like to see the order matching for yourself.. just go and look https://gitorious.org/intersango/intersango/blobs/master/cron/process_orders.php I've seen it. Do you have any comment on my post immediately previous to yours? Do you accept that orders are being matched at prices neither party requested? Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: phantomcircuit on July 14, 2011, 08:17:49 AM If you would like to see the order matching for yourself.. just go and look https://gitorious.org/intersango/intersango/blobs/master/cron/process_orders.php I've seen it. Do you have any comment on my post immediately previous to yours? Do you accept that orders are being matched at prices neither party requested? Can you point me to a specific order in which the order was filled at a price neither party requested? In the past the problem has been people putting in orders that were a terrible deal for themselves and them going through. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: realnowhereman on July 14, 2011, 10:02:32 AM In the past (and I reported it in the thread were dooglas subsequently posted a patch to fix it), I lost 30 BTC because britcoin matched an order at my limit price instead of the current market price.
Asking us to point at orders to prove the case won't work because the order book has changed in the meantime (I seriously doubt you are snapshotting the entire orderbook at every trade). It happened because I wanted to change a large sum of GBP into BTC. Looking at the orderbook I saw that it would mostly go through at the current best price, but I'd have to take a hit for the last bit of it. Let's say current bids were at 10 GBP. I entered a give want that was equivalent to a price of 12.8, which I knew was well above what was necessary to clear my whole sale instantly. Britcoin, instead of matching the 10 orders first, skipped those bids and matched the whole order at 12.8, leaving all the 10 GBP bids in the orderbook. Someone got a very good deal that day. Thank goodness I hadn't entered 100 GBP as an easy way of clearing fast. I didn't complain too loudly, because to be fair it says "alpha" all over britcoin; but when I did report it (http://forum.bitcoin.org/index.php?topic=4984.msg200608#msg200608), genjix just said "that's impossible"; until dooglas posted patch (http://forum.bitcoin.org/index.php?topic=4984.msg264777#msg264777). Then it wasn't impossible. It looks awfully like that patch either hasn't been applied, or there is another bug. Until britcoin was pulled from bitcoincharts, it was pretty obvious something was wrong because of the weird random spikes in the plot. I like britcoin, but you have to be careful when you're using it not to rely on it to get the best deal for you, it has bugs that will screw you over. Update: In the past the problem has been people putting in orders that were a terrible deal for themselves and them going through. No; the problem is that britcoin was (or is) matching the whole order at the limit price. When users enter that they are willing to accept 5 GBP per BTC; that doesn't mean they will only accept 5 GBP; it means they want as much as possible and will go as low as 5 GBP. Therefore if there are people offering 10 GBP in the orderbook, then those should be matched first. To not do so is not fair to either the buyers (who miss out on a sale), nor to the seller who wanted to accept multiple offers in the orderbook. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 14, 2011, 09:10:35 PM There are/were two separate issues. It used to be that new orders were being matched with existing orders at the price specified in the new order. So if there was an existing offer to sell me bitcoins for 10 GBP each and I asked to buy some at 5000 GBP each, I would be charged 5000 GBP for them, rather than 10 GBP each. I made a patch for this and it was applied around the 26th or 27th of June:
June 26, 2011, 06:08:15 am Merged dooglus's gitorious branch after testing it today. ;D June 27, 2011, 04:45:06 am yep, it was done a little afterwards since phantom forgot to do it. After that, new orders were initially matched at the price specified by existing orders, but if they were only partially matched, the "I have" and "I want" fields were updated by subtracting the amounts that were bought and sold by the initial trade. This leaves undesirable implied prices in the order, as I described in my recent post: This is how very high priced trades happen: User A has 5 BTC and wants 45 GBP (selling 5 BTC at 9 GBP/BTC) User B has 51 GBP and wants 5.1 BTC (buying 5.1 BTC at 10 GBP/BTC) User A's order goes in first, and is unmatched. User B's order goes in 2nd, and is partially matched at User A's rate of 9 GBP/BTC. User B gives 45 GBP to user A and gets 5 BTC in exchange. User B now has 6 GBP and the 'wants' value is updated to 0.1 BTC. User C can now come along and sell 0.1 BTC to User B for 6 GBP, at a price of 60 GBP/BTC even though the market price is in the range of 9 or 10 GBP/BTC. Note that overall, User B gets 5+0.1=5.1 BTC for his 45+6=51 GBP, and so actually gets the price he was expecting to. It's just that some was better than expected (5 bought from A for 9 GBP each) and some was much worse than expected (0.1 bought from C for 60 GBP each). Genjix claims that this "want" field isn't used, but it still is being used, and is the cause of this problem: June 26, 2011, 12:58:18 pm You're right, we do ignore the want field. It's mostly left for display and is kind of redundant. It's not even needed. Now phantomcircuit asks for a 'specific order' showing the problem. It's hard to give specific details, since we don't have access to the britcoin database. All we can see are the trades that are published through the API: Can you point me to a specific order in which the order was filled at a price neither party requested? In the past the problem has been people putting in orders that were a terrible deal for themselves and them going through. This "in the past" problem is the one that I fixed in my first patch, applied on June 26th or 27th. But bad trades have been happening since then to a lesser extent. Here's one: http://i55.tinypic.com/2ls9rb6.png I mentioned it in this post, and provided a fix: Did anyone notice the recent trade at 45 pence per BTC? Code: Fri Jul 1 10:21:01 2011 9.889100 2.214555 I think this was caused by the code still using the updated want_amount database field. I committed a fix for this a few days ago and mailed Genjix. The fix is here if anyone could look it over for me: https://gitorious.org/~dooglus/intersango/dooglus-intersango/commit/126d05d8f23a2745da8db65fb57414eca607d0d8 I don't have a copy of the orderbook at the time, but I really think it is unlikely that no buy orders were in the book for anything above 0.45 GBP when the price was around 10 GBP/BTC at the time. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: zebedee on July 16, 2011, 03:30:18 AM And true to form Britcoin continue to ignore the problem, and say it doesn't exist, despite
a) the buggy code (from a broken data model) being pointed out by dooglus several times now b) several trades matched at silly prices being pointed out to them. For a site entrusted with other people's money, whose owners deplore other exchanges for being "unprofessional", that is looking for FSA approval whilst being apparently unaware that the FSA has rules requiring "best execution", this is an arrogant and casual attitude in the extreme. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 16, 2011, 06:08:31 AM And true to form Britcoin continue to ignore the problem, and say it doesn't exist I don't think I've ever seen them say it doesn't exist. But I don't think I've seen them acknowledge it, either. This seems weird, since there so clearly is a problem. Here's an example from less than 24 hours ago - it's still showing up in the API right now: Code: Fri Jul 15 01:32:02 2011 8.865600 5.060000 It's a one bitcent trade. Are we to believe it moved the market price from 8.8 to 13.5? Here's the same trade on bitcoincharts: http://i53.tinypic.com/11wg6eg.png Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 18, 2011, 09:07:06 PM This one should be easy to find in the database. It's the most recent trade:
Code: Mon Jul 18 13:19:01 2011 7.571500 7.954886 The orderbook has plenty of people willing to buy around the 7 to 8 GBP price: http://i55.tinypic.com/dptsw5.png but the price crashed down to 1.5 GBP: http://i51.tinypic.com/rw3nyo.png Is anyone working on fixing this bug? Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: genjix on July 18, 2011, 10:26:50 PM Sorry this was my fault. I was supposed to be working on this before we transferred exchange development. At which point this task wasn't re-assigned to somebody.
We've had much more serious bureaucratic problems which we've been rushing around to fix and keep the site operational. Things to do with banks. Everybody has been working on a new exchange platform that is supposed to be more secure, better designed and scalable. Development hasn't been focusing on maintaining the current software since it was hoped the new site would be out within 2 weeks, and then 2 weeks more .etc Anyway, I'm looking at this myself over the next few days. It's not as simple as just merging your fix, since I really need to go through everything with a fine toothed comb, run test suites and make sure the algorithm is fully understood. Although from the previous work we paid you for, your patches were good. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 18, 2011, 11:19:44 PM Anyway, I'm looking at this myself over the next few days. It's not as simple as just merging your fix, since I really need to go through everything with a fine toothed comb, run test suites and make sure the algorithm is fully understood. Although from the previous work we paid you for, your patches were good. I can split my patch into smaller separate patches if that helps the process. I renamed the parameters of the 'pacman' function because they were really counter-intuitive as they were, and that's in the same patch that stops the "want" fields from being used to determine prices. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: genjix on July 19, 2011, 07:58:13 AM I have this:
1) Ignore the 'want_amount' column when deciding how much to trade. Only use the initially requested price and the amount column. 2) Update the 'want_amount' column for display only, based on the remaining 'amount' and the initially requested price. 3) Be more careful to process orders in the correct order. Previously prices were truncated at 4 decimal places. 4) Use clearer variable names in pacman() rather than confusing 'our' and 'them'. 5) Don't match with orders before they are 'processed'. 3) is done by using $order_by at the start of the fulfill_order main loop. 5) has the extra AND processed=TRUE in the matching orders select statement. 4) filled = us and partial = them and 2) I'm not too concerned about if there's a bug since it's only a display thing and easily fixable. That just leaves 1)... which I have to see actually works and test a whole bunch. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 19, 2011, 08:47:24 AM As a comment for 1) I should have written something like this:
Code: We're trading at 'their' price, which is determined by: That should help in understanding the change. Add it to the code if you like. For 2), you're right - once we stop using the 'want' fields to make the trades, it's just a display thing. It's mostly not a problem for long on the site, since the leftover order is usually quickly matched, but sometimes they stick around. Here's one: http://i53.tinypic.com/2yuavjs.png For 3), it was a problem with how MySQL defaults to only using 4 decimal places of precision when dividing. See this example: Code:
To fix it, I set div_precision_increment to 8 instead of 4, and make sure that the division has the bigger number on top, here: Code: if ($our->initial_amount > $our->initial_want_amount) Hope that helps! :) Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: genjix on July 19, 2011, 09:59:08 AM OK, but more correct for:
Code: To determine who 'swamps' who, we check whether: Would be to say that we're still using the same check as before: $our->amount >= $them->want_amount Except that we're not relying on the inaccurate want_amount: $our->amount >= $them->amount * $them->initial_want_amount / $them->initial_amount $our->amount * $them->initial_amount >= $them->amount * $them->initial_want_amount Which is the same as that end result above :) Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 19, 2011, 10:19:52 AM $our->amount >= $them->amount * $them->initial_want_amount / $them->initial_amount Which is the same as that end result above :) Exactly. Basically, it's: how_much_we_now_have >= how_much_they_can_now_afford_at_the_price_they_originally_set Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: genjix on July 19, 2011, 12:51:46 PM I ran it with fake data, but it still seems there, although a lot better.
Code: SELECT Code: | 21151 | 8.67436975 | 9.50000000 | 9.50000002 | 0.00000002 | 0 | 1 | 0 | Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: zebedee on July 19, 2011, 01:57:21 PM Hmm, reading the above, I wonder if I'm the only one thinking that storing price and amount would be a whole lot simpler?
And avoid bugs all over the place, from the GUI, to input, to trade matching? The first thing in writing an algorithm is to get your schema / data structures correct. The rest follows naturally. If the data structure isn't correct, you spend the rest of your time trying to cover that fact up. I'm glad it's being looked at, and I hope your new site does things properly, not in this half-assed way. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 19, 2011, 07:56:13 PM I ran it with fake data, but it still seems there, although a lot better. Code: SELECT I don't understand what you're doing here. Is this regarding point 3) in my path, and the precision of prices? Which table are you selecting from? I don't see any b_r in the database schema at all. Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 30, 2011, 07:17:25 PM I'm glad to see the 'absurd' prices have stopped happening since you started using my patch on the 19th... :)
http://i51.tinypic.com/o60i7s.png Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: mizerydearia on July 30, 2011, 09:58:05 PM ftfy
I'm glad to see the 'absurd' prices have stopped happening since britcoin started using my patch on the 19th... :) Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 30, 2011, 10:00:52 PM Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: mizerydearia on July 31, 2011, 01:42:05 PM I don't understand. What are you saying? http://www.urbandictionary.com/define.php?term=FTFY Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: dooglus on July 31, 2011, 07:02:54 PM I don't understand. What are you saying? http://www.urbandictionary.com/define.php?term=FTFY I know the acronym. I don't know what you were trying to say. You replaced the word 'you' (I was referring to britcoin in the 2nd person) to 'britcoin'. How is that fixing anything? Title: Re: official-britcoin readded to bitcoincharts/bitcoinwatch even with "absurd data" Post by: mizerydearia on August 01, 2011, 03:30:28 AM I know the acronym. I don't know what you were trying to say. You replaced the word 'you' (I was referring to britcoin in the 2nd person) to 'britcoin'. How is that fixing anything? My (first person) apologies for the meaningless/useless fix. Title: Re: unofficial-britcoin removed from bitcoincharts/bitcoinwatch due to "absurd data" Post by: mizerydearia on September 26, 2011, 10:09:30 PM cavirtex.com can't find public data I still can't find api for cavirtex.com. I see the data for virtex trades appear in #bitcoin-market on freenode, so there must be an api, right? Anyone know? |
