i'm writing a django app that features a timer like in a game.
lets say that the game is a basketball game and i have 4 quarters of 10 min.
i need that in the end of each of the 10 min the db will be changed.
to set a timer that will change the db won't work for me because the quarter
won't always be of 10 min, and it will be changed while the app is on
production, i.e i save the quarter time in the db so i can change it whenever
i want.
i thought to use signals but i just could't find a way to make it work.
any help will be good
thx
one way to think about it would be to say it doesn't matter what state the db is in when nobody is looking at it... in other words you don't have to update the db after exactly 10 minutes
instead: as each request comes in first check if you are past the limit of the timer, if so then update the db before continuing with the usual view code
Related
I have asked a few questions related to this personal project of mine already on this platform, and this should be the last one since I am so close to finishing. Below is the link to a mock example spreadsheet I've created, which mimics what my actual project does but it contains less sensitive information and is also smaller in size.
Mock Spreadsheet
Basic rundown of the spreadsheet:
Pulls data from a master schedule which is controlled/edited by another party into the Master Schedule tab.
In the columns adjacent to the imported data, an array formula expands the master schedule by classroom in case some of the time slots designate multiple rooms. Additional formulas adjust the date, start time, and end time to be capped within the current day's 24-hour period. The start time of each class is also made to be an hour earlier.
In the Room Schedule tab, an hourly calendar is created based on the room number in the first column, and only corresponds to the current day.
I have tested the spreadsheet extensively with multiple scenarios, and I'm happy with how everything works except for the calculation time. I figured the two volatile functions I use would take some processing time just by themselves, and I certainly didn't expect this to be lightning-fast especially without using a script, but the project that I am actually implementing this method for is much larger and takes a very long time to update. The purpose of this spreadsheet is to allow users to find an open room and "reserve" it by clicking the checkbox next to it (which will consequently color the entire row red) allowing everyone else to know that it is now taken.
I'd like to know if there is any way to optimize / speed up my spreadsheet, or to not update it every time a checkbox is clicked and instead update it "manually", similar to what OP is asking here. I am not familiar with Apps Script nor am I well-versed in writing code overall, but I am willing to learn - I just need a push in the right direction since I am going into this blind. I know the number of formulas in the Room Schedule tab is probably working against me yet I am so close to what I wanted the final product to be, so any help or insight is greatly appreciated!
Feel free to ask any questions if I didn't explain this well enough.
to speed up things you should avoid usage of the same formulae per each row and make use of arrayformulas. for example:
=IF(AND(TEXT(K3,"m/d")<>$A$1,(M3-L3)<0),K3+1,K3+0)
=ARRAYFORMULA(IF(K3:K<>"",
IF((TEXT(K3:K, "m/d")<>$A$1)*((M3:M-L3:L)<0), K3:K+1, K3:K+0), ))
=IF(AND(TEXT(K3,"m/d")=$A$1,(M3-L3)<0),TIMEVALUE("11:59:59 PM"),M3+0)
=ARRAYFORMULA(IF(K3:K<>"",
IF((TEXT(K3,"m/d")=$A$1)*((M3-L3)<0), TIMEVALUE("11:59:59 PM"), M3:M+0), ))
I have a project that uses an event hub to receive data, this is sent every second, the data is received by a website using SignalR, this is all working fine, i have been storing the data in to blob storage via a Stream Analytics Job, but this is really slow to access, and with the amount of data i am receiving off just 6 devices, it will get even slower as this increases, i need to access the data to display historical data on via graphs on the website, and then this is topped up with the live data coming in.
I don't really need to store the data every second, so thought about only storing it every 30 seconds instead, but into a SQL DB, what i am trying to do, is still receive the data every second but only store it every 30, i have tried a tumbling window, but from what i can see, this just dumps everything every 30 seconds instead of the single entries.
am i miss understanding the Tumbling, Sliding and Hopping windows, i am guessing i cannot use them in this way ? if that is the case, i am guessing the only way to do it, would be to have the output db as an input, so i can cross reference the timestamp with the current time ?
unless anyone has any other ideas ? any help would be appreciated.
Thanks
am i miss understanding the Tumbling, Sliding and Hopping windows
You are correct that this will put all events within the Tumbling/Sliding/Hopping window together. However, this is only valid within a group by case, which requires a aggregate function over this group.
There is a aggregate function Collect() which will create an array of the events within a group.
I think this should be possible when you group every event within a 30 second tumbling window using Collect(), then in the next step, CROSS APPLY each record, which should output all received events within the 30 seconds.
With Grouper AS (
SELECT Collect() AS records
FROM Input TIMESTAMP BY time
GROUP BY TumblingWindow(second, 30)
)
SELECT
record.ArrayValue.FieldA AS FieldA,
record.ArrayValue.FieldB AS FieldB
INTO Output
FROM Grouper
CROSS APPLY GetArrayElements(Grouper.records) AS record
If you are trying to aggregate 30 entries into one summary row every 30 seconds then a tumbling window is a good choice. Something like the following should work:
SELECT System.TimeStamp AS OutTime, TollId, COUNT(*) as cnt, sum(TollCharge) as TollCharge
FROM Input TIMESTAMP BY EntryTime
GROUP BY TollId, TumblingWindow(second, 30)
Thanks for the response, I have been speaking to my contact at Microsoft and he suggested something similar, I had also found something like that in various examples online. what I actually want to do, is only update the database with the data every 30 seconds. so I will receive the event, store it, and I will not store it again until 30 seconds have passed. I am not sure how I can do it with and ASA job to be honest, as I need to have a record of the last time it was updated, I actually have a connection to the event hub from my web site, so in the receiver, I am going to perform a simple check, and then store the data from there.
I'm pretty sure this question has been asked several times, but either I did not find the correct answer or I didn't understand the solution.
To my current problem:
I have a sensor which measures the time a motor is running.
The sensor is reset after reading.
I'm not interested in the time the motor was running the last five minutes.
I'm more interested in how long the motor was running from the very beginning (or from the last reset).
When storing the values in an rrd, depending on the aggregate function, several values are recorded.
When working with GAUGE, the value read is 3000 (10th seconds) every five minutes.
When working with ABSOLUTE, the value is 10 every five minutes.
But what I would like to get is something like:
3000 after the first 5 minutes
6000 after the next 5 minutes (last value + 3000)
9000 after another 5 minutes (last value + 3000)
The accuracy of the older values (and slopes) is not so important, but the last value should reflect the time in seconds since the beginning as accurate as possible.
Is there a way to accomplish this?
I dont know if it is useful for ur need or not but maybe using TREND/TRENDNAN CDEF function is what u want, look at here:
TREND CDEF function
I now created a small SQLite database with one table and one column in that tabe.
The table has one row. I update that row every time my cron job runs and add the current value to the current value. So the current value of the one row and column is the cumualted value of my sensor. This is then fed into the rrd.
Any other (better) ideas?
The way that I'd tackle this (in Linux) is to write the value to a plain-text file and then use the value from that file for the RRDTool graph. I think that maybe using SQLite (or any other SQL server) just to keep track of this would be unnecessarily hard on a system just to keep track of something like this.
I was implemnting some functionaliy in which i get a set of queries on database One shouldnt loose the query for a certain time lets say some 5min unless and untill the query is executed fine (this is incase the DB is down, we dont loose the query). so, what i was thinking to do is to set a sort of timer for each query through a different thread and wait on it for that time frame, and at the end if it still exists, remove it from the queue, but, i am not happy with this solution as i have to create as many threads as the number of queries. is there a better way to design this (environment is vc++), If the question is unclear, please let me know, i will try to frame it better.
One thread is enough to check lets say every 10 seconds that you do not have queries in that queue of yours whose due time has been reached and so should be aborted / rolled back.
Queues are usually grown from one end and erased from other end so you have to check only if the query on the end where the oldest items are has not reached its due time.
I'm trialing FluentMigrator as a way of keeping my database schema up to date with minimum effort.
For the release I'm currently building, I need to run a database script to make a simple change to a large number of rows of existing data (around 2% of 21,000,000 rows need to be updated).
There's too much data for to be updated in a single transaction (the transaction log gets full and the script aborts), so I use a WHILE loop to iterate through the table, updating 10,000 rows at a time, each batch in a separate transacticon. This works, and takes around 15 minutes to run to completion.
Now I have the script complete, I'm trying to integrate it into FluentMigrator.
FluentMigrator seems to run all the migrations for a single batch in one transaction.
How do I get FM to run each migration in a separate transaction?
Can I tell FM to not use a transaction for a specific migration?
This is not possible as of now.
There are ongoing discussions and some work already in progress.
Check it out here : https://github.com/schambers/fluentmigrator/pull/178
But your use case will surely help in pushing the things in the right direction.
You are welcome to take part to the discussion!
Maybe someone will find a temporary workaround?