I'd like to give my users the ability to change their slugs and have their old slugs redirect.
But after some time, I'd like to have the old slugs become available.
Is there an official or recommended way to do this?
I suppose it's as simple as running a nightly job which deletes records older than X days.
I don't think it's a great idea to do that because URL's stop being URL's anymore if you do that.
However a solution would be to go through FriendlyId history table every day and remove records which are older that given threshold.
Related
I am trying to get a historical list of the S&P500 underlying stocks mix. all tickers the dates were added to the S&P500 index mix and the dates tickers were removed from the list. and throughout the years for each period what is the mix. I did some search, doesn't seems to have any luck.
if anyone can provide some good search keywords, or suggest a place to look for would be appreciated
this is something very specific.
I currently use backtrader to work on some data. if there is a systematic way to get the data, please let me know as well.
many thanks.
You can access this data systematically in QuantRocket, via data provider Sharadar:
https://www.quantrocket.com/data/?filter=sharadar
Which is the best way to implement visitor's logic?
Create visitors table |ip|resource_type|resource_id|
Create serialize field in records (Post, Pet, Event, Ad, etc...)
Use nosql solutions
Any other idea
In the 1st case, we have extended the table size for every visit.
In the 2nd, we have a long field.
In the 3nd, I have trouble with mongoid at production (centOS).
Not sure I'm answering, but I would not implement that myself, but rather take a look at existing solutions. For basic counting :
Vanity
Google Analytics
For more detailed metrics about what each user does, I would go toward cohort.
A totally other option could be using just the log and something like lograge to log each request. It is very easy to add fields (such as the IP). You can then extract all the informations from your logs.
I want to build a data model which supports:
Data history - store every change of data. This is not a problem: http://en.wikibooks.org/wiki/Java_Persistence/Advanced_Topics#History
Data planning - user should be able to prepare a record with validity sometime in the future (for example, I know that customer name changes from May so I prepare record with validity of 1st of May).
How can I do point 2?
How can I do these things together (points 1 & 2)
If you really need point 2 - and I would think very hard about this, because in my experience users will never use it, and you will be spending a lot of effort to support something no one will ever use - anyway, if you really need it, then:
Make no changes at all directly in the table. All changes go through history.
Behind the scenes, periodically you will run a batch updater. This goes through history, finds all unapplied changes (set a status flag in the history to be able to rapidly find them), and applies them, and it checks the date to make sure it is time to apply the change.
You are going to have to deal with merges. What if the user says: In one month my name changes. Then goes in a and changes their name effective today. You have a conflict. How do you resolve it? You can either prevent any immediate changes, until past ones are done (or at least all new changes have a date after the last unapplied one). Or you can change it now, and change it again in a month.
I think storing the change of data is handled in the background, Look into data warehousing and slowly changing dimensions http://en.wikipedia.org/wiki/Slowly_changing_dimension in a Stored Procedure to handle new records and predecessors of those new records which will be known as "expired records". Once you allowed for SCD it's quite easy to find those historic expired records that you're after.
I'm a 'caching beginner' and I was looking at Spring's alternatives to solve the following requirements:
I have some time based data that is inserted into the database every minute. Once the data is inserted it will never be modified or deleted. Also, data will never be inserted in any days prior to the current one (no insertions 'in the past').
Users frequently request past data between a starting date and the current one. I would like their requests to be fulfilled by a mixed cache/database solution.
E.G. If an user requests last week of data once a day every day, I would like to access the cache for the first 6 days and the database for the last one. The cache would then be updated and I would have the same behavior the day after.
Is there a way to configure/implement this in a clean way using any of Spring's caching alternatives?
Thank you.
EHCache support all of this and more and it integrates with Spring nicely.
[update] - If I am reading your question right, you need to configure timeToLive and timeToIdle on your cache. All of this is documented in the main configuration page.
Here is the issue.
On a site I've recently taken over it tracks "miles" you ran in a day. So a user can log into the site, add that they ran 5 miles. This is then added to the database.
At the end of the day, around 1am, a service runs which calculates all the miles, all the users ran in the day and outputs a text file to App_Data. That text file is then displayed in flash on the home page.
I think this is kind of ridiculous. I was told they had to do this due to massive performance issues. They won't tell me exactly how they were doing it before or what the major performance issue was.
So what approach would you guys take? The first thing that popped into my mind was a web service which gets the data via an AJAX call. Perhaps every time a new "mile" entry is added, a trigger is fired and updates the "GlobalMiles" table.
I'd appreciate any info or tips on this.
Thanks so much!
Answering this question is a bit difficult since there we don't know all of your requirements and something didn't work before. So here are some different ideas.
First, revisit your assumptions. Generating a static report once a day is a perfectly valid solution if all you need is daily reports. Why hit the database multiple times throghout the day if all that's needed is a snapshot (for instance, lots of blog software used to write html files when a blog was posted rather than serving up the entry from the database each time -- many still do as an optimization). Is the "real-time" feature something you are adding?
I wouldn't jump to AJAX right away. Use the same input method, just move the report from static to dynamic. Doing too much at once is a good way to get yourself buried. When changing existing code I try to find areas that I can change in isolation wih the least amount of impact to the rest of the application. Then once you have the dynamic report then you can add AJAX (and please use progressive enhancement).
As for the dynamic report itself you have a few options.
Of course you can just SELECT SUM(), but it sounds like that would cause the performance problems if each user has a large number of entries.
If your database supports it, I would look at using an indexed view (sometimes called a materialized view). It should support allows fast updates to the real-time sum data:
CREATE VIEW vw_Miles WITH SCHEMABINDING AS
SELECT SUM([Count]) AS TotalMiles,
COUNT_BIG(*) AS [EntryCount],
UserId
FROM Miles
GROUP BY UserID
GO
CREATE UNIQUE CLUSTERED INDEX ix_Miles ON vw_Miles(UserId)
If the overhead of that is too much, #jn29098's solution is a good once. Roll it up using a scheduled task. If there are a lot of entries for each user, you could only add the delta from the last time the task was run.
UPDATE GlobalMiles SET [TotalMiles] = [TotalMiles] +
(SELECT SUM([Count])
FROM Miles
WHERE UserId = #id
AND EntryDate > #lastTaskRun
GROUP BY UserId)
WHERE UserId = #id
If you don't care about storing the individual entries but only the total you can update the count on the fly:
UPDATE Miles SET [Count] = [Count] + #newCount WHERE UserId = #id
You could use this method in conjunction with the SPROC that adds the entry and have both worlds.
Finally, your trigger method would work as well. It's an alternative to the indexed view where you do the update yourself on a table instad of SQL doing it automatically. It's also similar to the previous option where you move the global update out of the sproc and into a trigger.
The last three options make it more difficult to handle the situation when an entry is removed, although if that's not a feature of your application then you may not need to worry about that.
Now that you've got materialized, real-time data in your database now you can dynamically generate your report. Then you can add fancy with AJAX.
If they are truely having performance issues due to to many hits on the database then I suggest that you take all the input and cram it into a message queue (MSMQ). Then you can have a service on the other end that picks up the messages and does a bulk insert of the data. This way you have fewer db hits. Then you can output to the text file on the update too.
I would create a summary table that's rolled up once/hour or nightly which calculates total miles run. For individual requests you could pull from the nightly summary table plus any additional logged miles for the period between the last rollup calculation and when the user views the page to get the total for that user.
How many users are you talking about and how many log records per day?