I have the field named hits in my table which records user interaction with objects on my website. For example: if user views object preview field hits would be updated and increased by 1, if user enters object's page it would be increased by 3 and etc.
Everything works like a charm on my local development server. But on production server (online > 50) sometimes field hits increases by right value and then within several seconds it could be decreased by some random small value (1,2). This bug doesn't always occur. I think the solution can be related with MyISAM engine I'm currently using for this table.
Below is a code implementing table update query (codeigniter)
$this->db->set('hits', 'hits+' . (int) $count, FALSE);
$this->db->where('id', $id);
$this->db->update('gallery');
So I have 2 questions:
How to fix this bug?
How can I perform multiple queries to my table to duplicate this situation on my local development server?
Thanks to all for responses. Anyway I got useful information from your answers. The problem was at the crontask. I had a function running every minute every third month. It cutted these hits. I fixed that crontask and everything works now.
Check your crontask twice. Thanks you all for your help.
Related
I'm facing currently very, very strange behaviour.
I have an enterprise application, running on JBoss, the ORM is as you might expect hibernate and I'm doing some bulk operations.
I have a table and in that table there are all kind of fields and among the others there is a field of type DATETIME. In this field I'm saving user info, I have another field of the same type, configured with an trigger, so every time when the row is being updated the second DATETIME field is also updated.
I have a case where the first field should be increased with one second, so I'm doing bulk copy something like this:
UPDATE <TABLE_NAME> SET customerDATE = DATE_ADD(customerDATE, INTERVAL 1 SECOND)
My problem is that the query does not always work as expected.
What I see is that the second DATETIME field(the onne with the trigger) is being updated, together with some other fields, but the auto-increment with one second does not alway works(sometimes is also increased, sometimes not).
I tried searching for some known issues, but without success.
If anybody knows some problem in this direction I would really appreciate any help!
I'm testing now if there will be problems with more than an extra second.
Thanks in advance!
Ok, so what is the best practice when it comes down to paginating in mysql. Let me make it more clear, let's say that a given time I have 2000 records and there are more being inserted. And I am displaying 25 at a time, I know I have to use limit to paginate through the records. But what am I supposed to do for the total count of my records? Do I count the records every time users click to request the next 25 records. Please, don't tell me the answer straight up but rather point me in the right direction. Thanks!
The simplest solution would be to just continue working with the result set normally as new records are inserted. Presumably, each page you display will use a query looking something like the following:
SELECT *
FROM yourTable
ORDER BY someCol
LIMIT 25
OFFSET 100
As the user pages back and forth, if new data were to come in it is possible that a page could change from what it was previously. From a logical point of view, this isn't so bad. For example, if you had an alphabetical list of products and a new product appeared, then the user would receive this information in a fairly nice way.
As for counting, your code can allow moving to the next page so long as data is there to support a new page being added. Having new records added might mean more pages required to cover the entire table, but it should not affect your logic used to determine when to stop allowing pages.
If your table has a date or timestamp column representing when a record was added, then you might actually be able to restrict the entire result set to a snapshot in time. In this case, you could prevent new data from entering over a given session.
3 sugggestions
1. Only refreshing the data grid, while clicking the next button via ajax (or) storing the count in session for the search parameters opted .
2. Using memcache which is advanced, can be shared across all the users. Generate a unique key based on the filter parameters and keep the count. So you won't hit the data base. When a new record, gets added then you need to clear the existing memcache key. This requires a memache to be running.
3. Create a indexing and if you hit the db for getting the count alone. There won't be much any impact on performance.
I'm hoping this will be a rather simple question to answer, as I'm not looking for any specific code. I have a table on a classic asp page populated from an sql server. I've just set the table up so that each row is clickable and takes you to a page to edit the data in the row. My question is this: Would I be better off trying to use the recordset that populated the table or should I reconnect to the db and pull just the record I want edited.
As always; It Depends. It depends on what you need to edit about the record. It depends on How far apart your DB and site are from each other. It depends on which machine, if the DB and site are on separate machines, is more powerful.
That being said, you should make a new call for that specific record. The reason mainly being because of a specification you made in your question:
...and takes you to a page to edit the data in the row
You should not try to pass a record set between pages. There are a few reasons for this
Only collect what you need
Make sure data is fresh
Consider how your program will scale
On point 1 there are two ways to look at this. One is that you are trying to pass the entire record set across a page when you only need 1 record. There are few situations where another DB call would cost more than this. The other is you are only passing one record which would make me question your design. Why does this record set have every item related to a record. You are selecting way too much for just a result list. Or if the record is that small then Why do you need the new page. Why can you not just reveal an edit template for the item if it is that minimal.
On point 2 consider the following scenario. You are discussing with a coworker how you need to change a customer's record. You pull up this result set in an application but then nature calls and you step away from you desk. The coworker gets called by the customer and asked why the record is not updated yet. To placate the customer your coworker makes the changes. Now you are using an old record set and may overwrite additional changes your coworker made while you were away. This all happens because you never update the record set, you always just pass the old one from page to page.
On point 3 we can look back a point 1 a bit. let us say that you are passing 5 fields now. You decide though that you need a comments field to attach to one of your existing fields. do you intend to pass 2000 characters of that comment field to the next page? How about if each of the 5 need a comment field? Do you intend to pass 10,000 characters for a properly paged record set of 10? do you not do record set paging and need to pass 10,000 characters for a full 126 records.
There are more reasons too. Will you be able to keep your records secure passing them this way? Will this effect your user's experience because they have a crummy computer and cannot build that quick of a post request quickly? Generally it is better to only keep what you need and in most situations your result set should not have everything you need to edit.
I am working on a small application in Access Services on SharePoint to log colleagues leave requests, and I need to work out a data macro to calculate how many days of leave they have remaining from their allowance.
I have a table [Colleagues] with all of the user data, for simplicity I'll reduce it to [Email] and [Allowance] in days. I have another table which stores the requests [Requests] including the number of days to deduct in each approved leave request [Days Requested].
I have set up a query that returns all approved requests for the colleague and I would like to use a data macro that is triggered to run when the colleague logs in. As you cannot use aggregate functions in Web Applications, I am currently using ForEachRecord in the query to total the number of deductible days, however I cannot work out how to return that to a field in the [Colleague] record.
According to the Access help, I should be able to set the value to a LocalVar and use it in expressions as simply as referencing [Deductible Days], however this is not working.
Any help?
I finally worked this out after much tinkering.
In my query I included the [Colleague Email] field as well as the [Days Requested] field, and then when my Application loads it navigates to a form created from the [Colleagues] table. I have modified the Data Source of the form to link the [Email] field in the query results to the [Email] field in the [Colleagues] form.
Following this I was able to create an unbound textbox with the data source =Sum([Days Requested]) referring to the relevant field in the query. Voila! I now have the value to play around with in my application.
Hope that helps, took a lot of fiddling around. No data macros needed after all, but its a method I shall remember in future, opens up a lot of possibilities.
If I understand your situation correctly, I was faced with a very similar problem.
I believe the solution used here will work for you. It involves using a query to Sum up the values (we would use Sum where he used Count), use a Data Macro to run the query and then have have an On Insert/On Update trigger the Data Macro:
http://devspoint.wordpress.com/2014/03/26/validating-data-with-data-macros-in-access-services-2013/
Let me know if this works for you. It worked for me!
When I run this line of code
Movie.increment_counter :views, #moive.id
So the column views will be incremented twice (+2, not +1). In terminal I see this ran query to database:
UPDATE `movies` SET `views` = COALESCE(`views`, 0) + 1 WHERE `movies`.`id` = 8
If I attempt to run this query direct to MySQL, co the value of views is incremented correctly once (+1).
Any tips, what am I missing or I haven't set up?
Are you tracking page views by any chance? I ran into this as well- for every page load I would see the page view counter increment by three rather than 1, but only in production.
It turned out to be Google's Adsense code loading the page remotely. I noticed that they hit the page twice for every time one of my users would hit the page, effectively resulting in 3 page views. I suspect they do this to verify that content on the page meets their guidelines and to help match ads appropriately to page content. Check your httpd logs for Mediapartners-Google. I bet that's what's going on.
General advice: use Google Analytics (or similar service) for tracking page views. In my case I still needed to track this in a DB because I implement autocomplete based on "popularity" of certain page actions, but you might not need this.