Requirement:
To count the number of times a procedure has executed
From what I understand so far, sys.dm_exec_procedure_stats can be used for approximate count but that's only since the last service restart. I found this link on this website relevant but I need count to be precise and that should not flush off after the service restart.
Can I have some pointers on this, please?
Hack: The procedure I need to keep track of has a select statement so returns some rows that are stored in a permanent table called Results. The simplest solution I can think of is to create a column in Results table to keep track of the procedure execution, select the maximum value from this column before the insert and add one to it to increment the count. This solution seems quite stupid to me as well but the best I could think of.
What I thought is you could create a sequence object, assuming you're on SQL Server 2012 or newer.
CREATE SEQUENCE ProcXXXCounter
AS int
START WITH 1
INCREMENT BY 1 ;
And then in the procedure fetch a value from it:
declare #CallCount int
select #CallCount = NEXT VALUE FOR ProcXXXCounter
There is of course a small overhead with this, but doesn't cause similar blocking issue that could happen with using a table because sequences are handled outside transaction.
Sequence parameters: https://msdn.microsoft.com/en-us/library/ff878091.aspx
The only way I can think of keeping track of number of executions even when the service has restarted , is to have a table in your database and insert a row to that table inside your procedure everytime it is executed.
Maybe add a datetime column as well to collect more info about the execution. And a column for user who executed etc..
This can be done, easily and without Enterprise Edition, by using extended events. The sqlserver.module_end event will fire, set your predicates correctly and use a histogram target.
http://sqlperformance.com/2014/06/extended-events/predicate-order-matters
https://technet.microsoft.com/en-us/library/ff878023(v=sql.110).aspx
To consume the value, query the histogram target (under the reviewing target output examples).
Related
I have an API that i'm trying to read that gives me just the updated field. I'm trying to take that and update my tables using a stored procedure. So far the only way I have been able to figure out how to do this is with dynamic SQL but i would prefer to not do that if there is a way not to.
If it was just a couple columns, I'd just write a proc for each but we are talking about 100 fields and any of them could be updated together. One ticket might just need a timestamp updated at this time, but the next ticket might be a timestamp and who modified it while the next one might just be a note.
Everything I've read and have been taught have told me that dynamic SQL is bad and while I'll write it if I have too, I'd prefer to have a proc.
YOU CAN PERHAPS DO SOMETHING LIKE THIS:::
IF EXISTS (SELECT * FROM NEWTABLE NOT IN (SELECT * FROM OLDTABLE))
BEGIN
UPDATE OLDTABLE
SET OLDTABLE.OLDRECORDS = NEWTABLE.NEWRECORDS
WHERE OLDTABLE.PRIMARYKEY= NEWTABLE.PRIMARYKEY
END
The best way to solve your problem is using MERGE:
Performs insert, update, or delete operations on a target table based on the results of a join with a source table. For example, you can synchronize two tables by inserting, updating, or deleting rows in one table based on differences found in the other table.
As you can see your update could be more complex but more efficient as well. Using MERGE requires some proficiency, but when you start to use it you'll use it with pleasure again and again.
I am not sure how your business logic works that determines what columns are updated at what time. If there are separate business functions that require updating different but consistent columns per function, you will probably want to have individual update statements for each function. This will ensure that each process updates only the columns that it needs to update.
On the other hand, if your API is such that you really don't know ahead of time what needs to be updated, then building a dynamic SQL query is a good idea.
Another option is to build a save proc that sets every user-configurable field. As long as the calling process has all of that data, it can call the save procedure and pass every updateable column. There is no harm in having a UPDATE MyTable SET MyCol = #MyCol with the same values on each side.
Note that even if all of the values are the same, the rowversion (or timestampcolumns) will still be updated, if present.
With our software, the tables that users can edit have a widely varying range of columns. We chose to create a single save procedure for each table that has all of the update-able columns as parameters. The calling processes (our web servers) have all the required columns in memory. They pass all of the columns on every call. This performs fine for our purposes.
The question in short:
Can I call a stored procedure that has an output parameter in a data flow?
In long:
I have many tables to extract, transform, and load from one db to another one.
Almost all of the tables require one transformation which is fixing the country codes (from 3 letters to two). So my idea is as follows:
for each row: call the stored procedure, pass the wrong country code, replace the wrong code with the correct one (the output of the stored procedure)
There are at least two solutions for this:
Look-Up component: configuring it in advance mode and make sure the last sentence of the SProc is the Select statement that returns the good country code (e.g. SELECT #good_country_code)
Using an OLEDB Command
The latter (OLEDB Command) is actually quite simple, you need to configure it with:
EXEC ? = dbo.StoredProc #param1 = ?, #param2 = ?
As a consequence a #RETURN_VALUE will appear on the Available Destination Columns which you can then map to an existing column in the pipeline. Remember to create a new pipeline field/column (e.g. Good_Country_Code) using a Derived Column component before the OLEDB component and you'll have the chance to have both values, or replace the wrong one using another Derived Column component after OLEDB Command.
No, natively there isn't a component that is going to handle that. You can accomplish it with a Script Component but you don't want to.
What you're describing is a Lookup. The Data Flow Task has a Lookup Component but you'll be better served, especially for a finite list of values like Countries to push your query into the component.
SELECT T.Country3, T.Country2 FROM dbo.Table T;
Then you drag your SourceCountry column and match to Country3. Check Country2 and for all the rows that match, you'll get the 2 letter abbreviation.
A big disadvantage of trying to use your stored procedure is efficiency. The default Lookup is going to cache all those values. With the Script Version, say you have 10k rows come through, all with CAN. That's 10k invocations of your stored procedure where the results never change.
You do pay a startup cost as the default Lookup mode is Full Cache which means it's going to run your query and keep all those values local. This is great with your data set: 1000 countries max, 5 or 10 byte per row. That's nothing.
Yes, you can. You'll want to use a couple Execute SQL Tasks to do this.
Use an Execute SQL Task to gather a Result Set of Wrong_Country_Codes.
Add a ForEach Container as a successor to the previous Execute SQL Task. Pass the Result Set to this Container.
Inside that ForEach container, you will have another Execute SQL Task that will call your sproc, using each row (e.g. Wrong_Country_Code) as a variable parameter.
That should work. Only select the columns necessary to pass to your stored procedure.
Edit
In acknowledgement to the other answer, performance is going to be an issue. Perhaps rather than have the stored procedure produce an output, alter the sproc to do the updates for you.
I'm looking to create a simple web service that will make a call to a ms sql server. The database should then return a number that is simply incremented by 1 each time its called.
Notice that I'm not doing any insert or update, I just want the database to return a number every time the web service is called.
Can anyone provide the code for the stored procedure.
Thanks,
Samr
You could store the number in a table and UPDATE it, then SELECT (return) it, each time. If you decide to do this then you would first create the table, then create a stored procedure.
You should at least attempt to create the stored procedure (having created the table).
Sql server has a Create Sequence capability which is a single object that increments each time you query it. Read the fine print, it increments even though your transaction roles back.
I have a SQL Server 2005 stored proc which returns two result sets which are different in schema.
Another stored proc executes it as an Insert-Exec. However I need to insert the first result set, not the last one. What's a way to do this?
I can create a new stored proc which is a copy of the first one which returns just the result set I want but I wanted to know if I can use the existing one which returns two.
Actually, INSERT..EXEC will try to insert BOTH datasets into the table. If the column counts match and the datatype can be implicitly converted, then you will actually get both.
Otherwise, it will always fail because there is no way to only get one of the resultsets.
The solution to this problem is to extract the functionality that you want from the called procedure and incorporate it into the (formerly) calling procedure. And remind yourself while doing it that "SQL is not like client code: redundant code is more acceptable than redundant data".
In case this was not clear above, let me delineate the facts and options available to anyone in this situation:
1) If the two result sets returned are compatible, then you can get both in the same table with the INSERT and try to remove the ones that you do not want.
2) If the two result sets are incompatible then INSERT..EXEC cannot be made to work.
3) You can copy the code out of the called procedure and re-use it in the caller, and deal with the cost of dual-editing maintenance.
4) You can change the called procedure to work more compatibly with your other procedures.
Thats it. Those are your choices in T-SQL for this situation. There are some additional tricks that you can play with SQLCLR or client code but they will involve going about this a little bit differently.
Is there a compelling reason why you can't just have that first sproc return only one result set? As a rule, you should probably avoid having one sproc do both an INSERT and a SELECT (the exception is if the SELECT is to get the newly created row's identity).
Oo to prevent code from getting out of synch between the two processes, why not write a proc that does what you want to for the insert, call that in your process and have the orginal proc call that to get the first recordset and then do whatever else it needs to do.
Depending on how you get to this select, it is possible it might be refactored to a table-valued function instead of a proc that both processes would call.
In Oracle there is a mechanism to generate sequence numbers e.g.;
CREATE SEQUENCE supplier_seq
MINVALUE 1
MAXVALUE 999999999999999999999999999
START WITH 1
INCREMENT BY 1
CACHE 20;
And then execute the statement
supplier_seq.nextval
to retrieve the next sequence number.
How would you create the same functionality in MS SQL Server ?
Edit: I'm not looking for ways to automaticly generate keys for table records. I need to generate a unique value that I can use as an (logical) ID for a process. So I need the exact functionality that Oracle provides.
There is no exact match.
The equivalent is IDENTITY that you can set as a datatype while creating a table. SQLSERVER will automatically create a running sequence number during insert.
The last inserted value can be obtained by calling SCOPE_IDENTITY() or by consulting the system variable ##IDENTITY (as pointed out by Frans)
If you need the exact equivalent, you would need to create a table and then write a procedure to retun the next value and other operations. See Marks response on pitfalls on this.
Edit:
SQL Server has implemented the Sequence similar to the Oracle. Please refer to this question for more details.
How would you implement sequences in Microsoft SQL Server?
Identity is the best and most scalable solution, BUT, if you need a sequence that is not an incrementing int, like 00A, 00B, 00C, or some special sequence, there is a second-best method. If implemented correctly, it scales OK, but if implemented badly, it scales badly. I hesitate to recommend it, but what you do is:
You have to store the "next value" in a table. The table can be a simple, one row, one column table with just that value. If you have several sequences, they can share the table, but you might get less contention by having separate tables for each.
You need to write a single update statement that will increment that value by 1 interval. You can put the update in a stored proc to make it simple to use and prevent repeating it in code in different places.
Using the sequence correctly, so that it will scale reasonably (no, not as well as Identitiy :-) requires two things: a. the update statement has a special syntax made for this exact problem that will both increment and return the value in a single statement; b. you have to fetch the value from the custom sequence BEFORE the start of a transaction and outside the transaction scope. That is one reason Identity scales -- it returns a new value irrespective of transaction scope, for any attempted insert, but does not roll back on failure. That means that it won't block, and also means you'll have gaps for failed transactions.
The special update syntax varies a little by version, but the gist is that you do an assignment to a variable and the update in the same statement. For 2008, Itzik Ben-Gan has this neat solution: http://www.sqlmag.com/Articles/ArticleID/101339/101339.html?Ad=1
The old-school 2000 and later method looks like this:
UPDATE SequenceTable SET #localVar = value = value + 5
-- change the tail end to your increment logic
This will both increment and return you the next value.
If you absolutely cannot have gaps (resist that requirement :-) then it is technically possible to put that update or proc in side the rest of your trnsaction, but you take a BIG concurrency hit as every insert waits for the prior one to commit.
I can't take credit on this; I learned it all from Itzik.
make the field an Identity field. The field will get its value automatically. You can obtain the last inserted value by calling SCOPE_IDENTITY() or by consulting the system variable ##IDENTITY
The SCOPE_IDENTITY() function is preferred.
As DHeer said there is absolutely no exact match. If you try to build your own procedure to do this you will invariably stop your application from scaling.
Oracle's sequences are highly scalable.
OK, I take it back slightly. If you're really willing to focus on concurrency and you're willing to take numbers out of order as is possible with a sequence, you have a chance. But since you seem rather unfamiliar with t-sql to begin with, I would start to look for some other options when (porting an Oracle app to MSSS - is that what you're doing)
For instance, just generate a GUID in the "nextval" function. That would scale.
Oh and DO NOT use a table for all the values, just to persist your max value in the cache. You'd have to lock it to ensure you give unique values and this is where you'll stop scaling. You'll have to figure out if there's a way to cache values in memory and programmatic access to some sort of lightweight locks- memory locks, not table locks.
I wish that SQL Server had this feature. It would make so many things easier.
Here is how I have gotten around this.
Create a table called tblIdentities. In this table put a row with your min and max values and how often the Sequence number should be reset. Also put the name of a new table (call it tblMySeqNum). Doing this makes adding more Sequence Number generators later fairly easy.
tblMySeqNum has two columns. ID (which is an int identity) and InsertDate (which is a date time column with a default value of GetDate()).
When you need a new seq num, call a sproc that inserts into this table and use SCOPE_IDENTITY() to get the identity created. Make sure you have not exceeded the max in tblIdentities. If you have then return an error. If not return your Sequence Number.
Now, to reset and clean up. Have a job that runs as regularly as needed that checks all the tables listed in tblIdentites (just one for now) to see if they need to be reset. If they have hit the reset value or time, then call DBCC IDENT RESEED on the name of the table listed in the row (tblMySeqNum in this example). This is also a good time to clear our the extra rows that you don't really need in that table.
DON'T do the cleanup or reseeding in your sproc that gets the identity. If you do then your sequence number generator will not scale well at all.
As I said, it would make so many things easier of this feature was in SQL Server, but I have found that this work around functions fairly well.
Vaccano
If you are able to update to SQL Server 2012 you can use SEQUENCE objects. Even SQL Server 2012 Express has support for sequences.
CREATE SEQUENCE supplier_seq
AS DECIMAL(38)
MINVALUE 1
MAXVALUE 999999999999999999999999999
START WITH 1
INCREMENT BY 1
CACHE 20;
SELECT NEXT VALUE FOR supplier_seq
SELECT NEXT VALUE FOR supplier_seq
SELECT NEXT VALUE FOR supplier_seq
SELECT NEXT VALUE FOR supplier_seq
SELECT NEXT VALUE FOR supplier_seq
Results in:
---------------------------------------
1
(1 row(s) affected)
---------------------------------------
2
(1 row(s) affected)
---------------------------------------
3
(1 row(s) affected)
---------------------------------------
4
(1 row(s) affected)
---------------------------------------
5
(1 row(s) affected)
Just take care to specify the right data type. If I hadn't specified it the MAXVALUE you've provided wouldn't be accepted, that's why I've used DECIMAL with the highest precision possible.
More on SEQUENCES here: http://msdn.microsoft.com/en-us/library/ff878091.aspx
This might have already been answered a long time ago... but from SQL 2005 onwards you can use the ROW_NUMBER function... an example would be:
select ROW_NUMBER() OVER (ORDER BY productID) as DynamicRowNumber, xxxxxx,xxxxx
The OVER statement uses the ORDER BY for the unique primary key in my case...
Hope this helps... no more temp tables, or strange joins!!
Not really an answer, but it looks like sequences are coming to SQLServer in 2012.
http://www.sql-server-performance.com/2011/sequence-sql-server-2011/
Not an exact answer but addition to some existing answers
SCOPE_IDENTITY (Transact-SQL)
SCOPE_IDENTITY, IDENT_CURRENT, and ##IDENTITY are similar functions
because they return values that are inserted into identity columns.
IDENT_CURRENT is not limited by scope and session; it is limited to a
specified table. IDENT_CURRENT returns the value generated for a
specific table in any session and any scope. For more information, see
IDENT_CURRENT (Transact-SQL).
It means two different sessions can have a same identity value or sequence number so to avoid this and get unique number for all sessions use IDENT_CURRENT
Exactly because of this
IDENT_CURRENT is not limited by scope and session; it is limited to a specified table.
we need to use SCOPE_IDENTITY() because scope identity will give us unique number generated in our session, and uniqueness is provided by identity itself.