Is there a simple way to change the maximum possible rested bonus that a given character can accumulate? I don't see anything in the config, or in any of the tables in World_DB or Character_DB.
Related
on Flyway deployment script name starts with a version.
What is the maximum length one can use? I see that on the table column holding the version is 50 character long
There are a number of limits:
Version must be 50 characters or less
Description must be 200 characters or less
Migration filenames must be compatible with any OS limit
Do you have a specific use case for a version string longer than 50 characters? We're in the middle of work for Flyway 7 and this is a chance for us to change the history table if there's a good reason to do so.
If you read the documentation located here, you'll find that the limit is not one from Flyway. Rather, your limit on the length of the version is based on the OS and it's limit on the size of a file name. You must ensure that you're incrementing your numbers in an appropriate order. However, as you can see in the docs, Flyway supports a wide variety of formats, and the length of your string defining the version number is not an issue you need to worry about.
I have a datacenter A which has 100GB of the file changing every millisecond. I need to copy and place the file in Datacenter B. In case of failure on Datacenter A, I need to utilize the file in B. As the file is changing every millisecond does r-sync can handle it at 250 miles far datacenter? Is there any possibility of getting the corropted file? As it is continuously updating when we call this as a finished file in datacenter B ?
rsync is a relatively straightforward file copying tool with some very advanced features. This would work great for files and directory structures where change is less frequent.
If a single file with 100GB of data is changing every millisecond, that would be a potential data change rate of 100TB per second. In reality I would expect the change rate to be much smaller.
Although it is possible to resume data transfer and potentially partially reuse existing data, rsync is not made for continuous replication at that interval. rsync works on a file level and is not as commonly used as a block-level replication tool. However there is an --inplace option. This may be able to provide you the kind of file synchronization you are looking for. https://superuser.com/questions/576035/does-rsync-inplace-write-to-the-entire-file-or-just-to-the-parts-that-need-to
When it comes to distance, the 250 miles may result in at least 2ms of additional latency, if accounting for the speed of light, which is not all that much. In reality this would be more due to cabling, routers and switches.
rsync by itself is probably not the right solution. This question seems to be more about physics, link speed and business requirements than anything else. It would be good to know the exact change rate, and to know if you're allowed to have gaps in your restore points. This level of reliability may require a more sophisticated solution like log shipping, storage snapshots, storage replication or some form of distributed storage on the back end.
No, rsync is probably not the right way to keep the data in sync based on your description.
100Gb of data is of no use to anybody without without the means to maintain it and extract information. That implies structured elements such as records and indexes. Rsync knows nothing about this structure therefore cannot ensure that writes to the file will transition from one valid state to another. It certainly cannot guarantee any sort of consistency if the file will be concurrently updated at either end and copied via rsync
Rsync might be the right solution, but it is impossible to tell from what you have said here.
If you are talking about provisioning real time replication of a database for failover purposes, then the best method is to use transaction replication at the DBMS tier. Failing that, consider something like drbd for block replication but bear in mind you will have to apply database crash recovery on the replicated copy before it will be usable at the remote end.
Not sure if this is the right subreddit to ask this question, but I will give it a shot. There is the ICAO standard for Machine Readable Zones as described here https://en.wikipedia.org/wiki/Machine-readable_passport. I don't see the point for check digits there.
If I have F instead of 5 for example in the MRZ code somewhere in the second line for example, all the checkdigits will be the same. What is the point in the first place for those check digits in the ICAO standard? Especially I don't see the point of the last check digits calculation since you could also calculate it by using the check digits from the second line and not all the letters/numbers.
Could someone explain why we need those checkdigits?
To be fair. This is not a subreddit. Anyway, there are multiple reasons that there are check digits inside the MRZ. The first reason is that automatic readers can check if the code is read well enough. The second reason is that it prevents a lot of fraud and identification theft. Some people that alter their travel documents do not know that there are check digits in place. So some people will get caught because they fail to edit the numbers.
Some countries now include PDF417 barcodes and/or QR-codes to reach better reads by machines. But keep in mind that not all governments/countries have access to high-tech devices, so the machine readable zone is still mandatory for a check with the naked eye.
Source: I work for a travel document verification company.
MRZ check digits are calculated on subsections of the entire MRZ. Each calculation serves as a check for each section. A final check digit is calculated on the sum of each sections and this digit serves as a double check of the individual check.
The below have same check digit of 8:
123456780
128456785
Whereas the subsection check digit matched after the tampering but the final check digit will detect this. Therefore, the final check digit adds additional robustness.
Although, I am wondering whether this visual check digit is mandatory because an eMRTD NFC chip BAC protocol also does a much stronger cryptographic check of the MRZ value.
UPDATES: My original claim that the composite check digit adds robustness to tampering is incorrect. Given the below TD1 MRZ:
IDSLV0012345678<<<<<<<<<<<<<<<
9306026F2708252SLV<<<<<<<<<<<4
JOHN<SMEAGOL<<WENDY<LIESSETTEF
An OCR scanner can either gave 0012345678 or OO12345678 for the document number portion and all check digits passes including the composite check digit. But there is no way to tell which document number is correct. It seems that an MRZ check digit has edge cases that cannot be helped.
I'm doing a cousework for a distributed sytems module, and within it I neef to apply a variable clock incrementor; my tutor has gone over both Lamport and Vector clocks, but said "I cant hint at that" when I asked him about applying a variable length/size per clock.
I wish I knew what to do,
Andy
I suppose you mean vector clocks of variable size?
This is technically not possible due to the way vector clocks are defined and used, however it brings the problem, that you would need to know about all nodes which will communicate together and use a vector clock right in the beginning. This way you wouldn’t be allowed to expand your service, and also if you tear down a node, to never start it again, the time for it would be still sent around and waste resources.
One of my professors in distributed systems mentioned, that Amazon is/was using “dynamic” vector clocks for some services, and they had an algorithm which automatically removed “old” entries from the vector clcoks. They supposesdly concluded something like, this worked so far fine. However I never saw the paper about this.
So I have a website which has three spaces for pictures: Space A, Space B, and Space C.
In Space A, I have 20 images (Images A1-A20) which I would like to rotate daily.
In Space B, I have 20 images (Images B1-B20) which I would like to change every 13 days.
In Space C, I have 20 images (Images C1-C20) which I would like to change every 20 days.
Therefore, let's say for instance I wanted my site to start based on Jan 1, 2000.
Spaces A,B,&C would have the following images based on the date:
1/1 - A1,B1,C1
1/2 - A2,B1,C1
1/3 - A3,B1,C1
...
1/12 - A12,B1,C1
1/13 - A13,B1,C1
1/14 - A14,B2,C1
1/15 - A15,B2,C1
...
1/20 - A20,B2,C1
1/21 - A1,B2,C2
1/22 - A2,B2,C2
1/23 - A3,B2,C2
...
1/26 - A6,B2,C2
1/27 - A7,B3,C2
1/28 - A8,B3,C2
etc.
Therefore, I think I need a DateTime program that finds the number of elapsed days between the starting date (Jan 1, 2000), and the date listed on the computer, divides by the appropriate number (20,260,400), uses the remainder or fraction to determine which picture is appropriate and picks it to display, but haven't a clue how to write it / where to start.
Suggestions appreciated.
Thanks, NP
If you've been looking for a reason to learn php or perl or similar, this is it. If not, then try rent-a-coder or similar. There's a lot more to getting your first program working than just the code--you need to figure out how to get the software loaded and working correctly on your server.
The good news is that you seem to know your problem statement well. I'd go to a bookstore and look at the php or perl books until you see one that seems helpful, then go for it. And we here at SO stand ready to answer all questions from true seekers...
ps. For your problem, php would be a good starting bet if you're using a Linux web server.
Larry K is correct in that you have the problem pretty well defined and will need some sort of program to do this. PHP and Perl would be good choices, but there are ways in which you could do this with virtually any language: Python, C, Ruby, .... One technique would be to run a cron job (assuming Linux or another Unix variant) to re-write your HTML file every day (at midnight or thereabouts). Another would be to write a CGI script to determine the proper images when the page is requested. The PHP way (or Perl or Python if using mod_perl or mod_python) would embed (or pull in) the code directly in the web page and execute when the page is requested. I suggest you play around and pick what works best for you and your situation.
FWIW, if it were me, and I could do it any way I liked, I'd probably write a Python script to run as a cron job. Python just because that's currently my favorite language, and doing it by a cron job minimizes the processing required to do the job by doing it just once per day. However, some web hosting companies don't provide cron (or Python :-( ); if that were the case, I'd do it with PHP embedded in the web page, assuming I could use PHP (which seems ubiquitous with web hosting companies).