I am trying to create a sequence in snowflake with max value and cycle.
However I am not able to find any document where it says how to provide the max value.
But again I see in doc it says Snowflake will throw error if threshold is reach.
Can somebody please suggest how to create the below sequence in snowflake.
create or replace sequence myseq as bigint
start with 10000
increment by 1
no min value
maxvalue 2000000
no cycle;
And If any body can suggest what is the max value of sequence in snowflake. If I create it without datatype.
The answer is here:
A sequence value can represent a 64-bit two’s complement integer (-2^63 to 2^63 - 1). If the internal representation of a sequence’s next value exceeds this range (in either direction) an error results and the query fails. Note that this may result in losing these sequence values.
This is mentioned on Snowflake docs here.
Snowflake doesn't support cycling of sequences
Related
I have a design problem that I'm looking for an efficient way to solve:
I have three instances of a single service running. Each instance is totally stateless and exposes a single endpoint /token. When the /token endpoint is called by a client, a random number is returned. The random number is generated by a non-repeating pseudo-random number generator which generates a unique random integer for the first n-times it is called and then repeat the same sequence the next n-times it is called. In other words, it's a repeating cycle of n values. So say n = 20, it'll return unique values within the range of 0 to 20 for the first 20 times it is called.
The problem here is: given that I have three instances of this service running, how do I avoid duplicating random integers since any of the services can't know what random value has been generated by either of them.
Here's what I've done:
I have passed as enviroment variable, a seed value that ensures that all the services are generating the same random sequence.
I have setup a database that each of these services can access remotely. It has a table with a single column map set to a default value of 0
When the client calls the /token endpoint of a service, the service increases the value in the map column by 1 and fetches the resulting value.
I then return the random number this resulting value maps to in the random sequence
Is the above approach efficient ?
Could the services experience a race condition when trying to access the database row ?
Could this problem be solved without a database ?
Suggestions would be really appreciated.
Thanks in advance
Sounds like snowflake could be used -
Instead of regular integers, well they will be integers again but you will need to encode a bit of information inside them, you can construct them so they encode the information bitwise.
So let's say your integers will be 64 bits. You can leave x bits for service, you can leave y bits for seed and z bits for the "real" id.(for example datetime ticks).
Doing this you will have something like 0001 (serviceid) (x=4) 1010 (z=4) (your n=20) 0101....0 (56 bits for datetime ticks).
So now you can identify your generated numbers by serviceId, give them some seed (maybe configuration) and some "real" part.
More on snowflake you can probably find from here.
So I'm trying to create a new variable column of ''first differences'' by subtracting values in the SAME column but have no clue how to do so on SPSS. For example, in this picture:
1st value - 0 = 0 (obviously). 2nd value - 1st value =..., 3rd value - 2nd value =..., 4th value - 3rd value =... and so on.
Also, if there is a negative number, does SPSS allow me to log it/regress it? Once I find the first difference, I'm going to LOG it & then regress it. For context, the reason I'm doing this is part of a bigger equation to find out how economic growth and a CHANGE in economic growth (hence the first difference and log) will affect the variable im studying.
Thanks.
To calculate differences between values in consecutive rows use this:
if $casenum>1 diffs = FinalConsumExp - lag(FinalConsumExp).
execute.
If you need help with additional problems please start a separate question for each problem.
HTH.
I know that similar questions have been asked again in the past, but I think my case is slightly different. I have a column which has Logarithmic values and I'm trying to invert them using the following formula:
SELECT POWER(10,CAST(9.695262723 AS NUMERIC(30,15)))
Let's say the value 9.695262723 is one of the values of that column.
When trying to run this query I get an Arithmetic overflow error for type int, value = 4957500001.400178.
On the other hand, the same query works fine for smaller values e.g. SELECT POWER(10,CAST(8.662644523 AS NUMERIC(30,15)))
How could I overcome that error and calculate the inverse values of the log10 entries I have? Just for information the greater value that exists in the table (in log10 scale) is 12.27256096.
The problem here is your first input parameter (10) which SQL server will, by default, treat as the datatype int.int has a maximum value of 2^31-1 (2,147,483,647), and the number 4,957,500,001 is far larger than this, so you need to use a bigint:
SELECT POWER(CONVERT(bigint,10),CONVERT(numeric(30,15),9.695262723));
Edit: If you need to retain the decimal places, then use a numeric with a large enough scale and precision, instead of bigint.
Recently, I came across an anomaly that while dividing two integers, I am getting only the quotients and reminders are simply ignored.
SELECT 12/8,12%8
The above query gives 1 and 4 respectively, which is similar to Java/C programming. Again applying Java/C programming methods used below calculations to obtain the expected value.
SELECT 12.0/8,12/8.0
The answer is 1.5000 and 1.5000 respectively.
Working on my task I got a situation to obtain percentage value across two counted values (integers) and I stuck up with the results similar to the former query. Then I worked out through the same by multiplying one of the value with 1.0 . This solved my issue.
But later on, going through few scripts, used in my project (developed long back), I noticed in certain cases the decimal values are returned from the query even though two counted values (whole numbers) are divided.
I first noticed this in Netezza. But same holds true in SQL Server as well.
Please advise on what basis the datatypes of returned values are decided.
When dividing both integers, it will perform integer division, which returns an integer. To perform floating point division, you must either cast one or both of the operands to float/decimal/double.
SELECT cast(12 as float)/8
SELECT 12/cast(8 as float)
SELECT cast(12 as float)/cast(8 as float)
SELECT cast(12/8 as float)
Note that the last query is different since the integer division is performed first before casting to float,that is why the decimal value was already lost.
I have a table with IDs and locales. The same ID can be listed more than once with a different locale:
ID Locale
123456 EN_US
234567 EN_US
234567 EN_CA
345678 EN_US
I need to create an unique identifier in the form of an numeric ID (Integer) for each record, while maintaining the ability to reverse engineer the original components.
I was thinking bit shifting might work: assign a numerical value to each locale, but I'm not quite sure how to implement. Has anyone faced this challenge before? Also, I have 75 locales so I'm not sure if that would be an issue with bit shifting.
Lastly, I'm using SQL Server with a Linked Server connection to Teradata (that's my data source). I don't think Teradata supports bitwise out-of-the-box so I'm assuming I'll have to do it in MSSQL.
Thank you.
You can create a composite numeric key, mapping your 75 unique values into the last 2 digits of the numeric key. You can parse into components with simple modulus 100 arithmetic or just a substring. If you will ever exceed 100 values, use 3 digits instead. 9 digits total will fit int an int, 10-18 will fit in a bigint.
Converting 234567-EN_US into an integer is easy. Just use CHECKSUM on the concatenated string value. It would not be reversible, however.
You could store this CHECKSUM value on the original table, however, and then use it to backtrack from whatever table you're going to store the integer in.
Another solution would be to assign each locale an Integer value (as Marc B suggested). Call that X. Then call your existing integer ID (234567) as Y. Your final key would be (X * 1,000,000) + Y. You could then reverse the formula to get the values back. This would only work, of course, if your existing integer IDs are well below 1,000,000, and also if your final integer can be a BigInt.