SQL server linked server to oracle 8000 limit - oracle

I have a query that is longer than 8000 in length I tried to execute it following way but it wouldn't. I used this link for help.
Declare #query1 As varchar(8000)
Declare #query2 As varchar(8000)
SELECT TOP 1000 *
FROM OPENQUERY(OPTIMA,#query1+#query2)
The Error:
Msg 102, Level 15, State 1, Line 74
Incorrect syntax near '#query1'.
I am not allowed to create view or stored procedure in remote server.

OPENQUERY() has a builtin limitation of 8KB on your #query, you also are not allowed to use variables for the inputs (in attempt to circumvent the 8KB limit).
I will still recommend creating a stored proc on your target server and calling it with OPENQUERY() that way.
Reference: http://msdn.microsoft.com/en-us/library/ms188427.aspx

Make a new view to the Oracle DB of the your query so you can decrease query length.

I had the same problem a couple of days ago, basically i was using 'UNION ALL' to union multiple queries inside the openquery.
My solution to this was to union on the local server instead of the remote server, it didn't increase the number of rows being pulled thought the wire because i was using union all anyway, it just forced me to use multiple openquery statements instead of a single one.
It did the job (since I'm not authorized to do anything on the remote server).
If you can, both hkf and Jokke Heikkilä have the correct answers, just do an sp or view on the remote server.

Related

Oracle Data Integrator and odiRef.getSession

I'm having some troubles with ODI logs.
I'm trying to get the logs from the Snp_session, using the session number from this:
select <%=odiRef.getSession("SESS_NO")%> from dual
Unfortunately, it's not always right, and actualy it get the wrong session number quite often, like 1 every 10 times.
Is it an expected behaviour, or is there another way to get the right session?
Edit:
Corrected mistyping error
Not sure why this is working at all… Last time I checked (ODI 11g) this syntax required extra = character (passing over output from ODI Substitution API directly). Can you try:
SELECT <%=odiRef.getSession("SESS_NO")%> FROM dual
?

After upgrading from Sql Server 2008 to Sql Server 2016 a stored procedure that was fast is now slow

We have a stored procedure that returns all of the records that fall within a geospatial region ("geography"). It uses a CTE (with), some unions, some inner joins and returns the data as XML; nothing controversial or cutting edge but also not trivial.
This stored procedure has served us well for many years on SQL Server 2008. It has been running within 1 sec on a relatively slow server. We have just migrated to SQL Server 2016 on a super fast server with lots of memory and a super fast SDDs.
The entire database and associated application is going really fast on this new server and we are very happy with it. However this one stored procedure is running in 16 sec rather than 1 sec - against exactly the same parameters and exactly the same dataset.
We have updated the indexes and statistics on this database. We have also changed the compatibility level of the database from 100 to 130.
Interesting, I have re-written the stored procedure to use a temporary table and 'insert' rather than using the CTE. This has brought the time down from 16 sec to 4 sec.
The execution plan does not provide any obvious insights into where a bottleneck may be.
We are a bit stuck for ideas. What should we do next? Thanks in advance.
--
I have now spent more time on this problem than i care to admit. I have boiled down the stored procedure to the following query to demonstrate the problem.
drop table #T
declare #viewport sys.geography=convert(sys.geography,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
declare #outputControlParameter nvarchar(max) = 'a value passed in through a parameter to the stored that controls the nature of data to return. This is not the solution you are looking for'
create table #T
(value int)
insert into #T
select 136561 union
select 16482 -- These values are sourced from parameters into the stored proc
select
[GeoServices_Location].[GeographicServicesGatewayId],
[GeoServices_Location].[Coordinate].Lat,
[GeoServices_Location].[Coordinate].Long
from GeoServices_Location
inner join GeoServices_GeographicServicesGateway
on GeoServices_Location.GeographicServicesGatewayId = GeoServices_GeographicServicesGateway.GeographicServicesGatewayId
where
(
(len(#outputControlParameter) > 0 and GeoServices_Location.GeographicServicesGatewayId in (select value from #T))
or (len(#outputControlParameter) = 0 and GeoServices_Location.Coordinate.STIntersects(#viewport) = 1)
)
and GeoServices_GeographicServicesGateway.PrimarilyFoundOnLayerId IN (3,8,9,5)
GO
With the stored procedure boiled down to this, it runs in 0 sec on SQL Server 2008 and 5 sec on SQL Server 2016
http://www.filedropper.com/newserver-slowexecutionplan
http://www.filedropper.com/oldserver-fastexecutionplan
Windows Server 2016 is choking on the Geospatial Intersects call with 94% of the time spent there. Sql Server 2008 is spending its time with with a bunch of other steps including Hash Matching and Parallelism and other standard stuff.
Remember this is the same database. One has just been copied to a SQL Server 2016 machine and had its compatibility level increased.
To get around the problem I have actually rewritten the stored procedure so that Sql Server 2016 does not choke. I have running in 250msec. However this should not have happened in the first place and I am concerned that there are other previously finely tuned queries or stored procedures that are now not running efficiently.
Thanks in advance.
--
Furthermore, I had a suggestion to add the traceflag -T6534 to start up parameter of the service. It made no difference to the query time. Also I tried adding option(QUERYTRACEON 6534) to the end of the query too but again it made no difference.
From the query plans you provided I see that spatial index is not used on newer server version.
Use spatial index hint to make sure query optimizer chose the plan with spatial index:
select
[GeoServices_Location].[GeographicServicesGatewayId],
[GeoServices_Location].[Coordinate].Lat,
[GeoServices_Location].[Coordinate].Long
from GeoServices_Location with (index ([spatial_index_name]))...
I see that the problem with the hint is OR operation in query predicate, so my suggestion with hint actually won’t help in this case.
However, I see that predicate depends on #outputControlParameter so rewriting query in order to have these two cases separated might help (see my proposal below).
Also, from your query plans I see that query plan on SQL 2008 is parallel while on SQL 2016 is serial. Use option (recompile, querytraceon 8649) to force parallel plan (should help if your new superfast server has more cores then the old one).
if (len(#outputControlParameter) > 0)
select
[GeoServices_Location].[GeographicServicesGatewayId],
[GeoServices_Location].[Coordinate].Lat,
[GeoServices_Location].[Coordinate].Long
from GeoServices_Location
inner join GeoServices_GeographicServicesGateway
on GeoServices_Location.GeographicServicesGatewayId = GeoServices_GeographicServicesGateway.GeographicServicesGatewayId
where
GeoServices_Location.GeographicServicesGatewayId in (select value from #T))
and GeoServices_GeographicServicesGateway.PrimarilyFoundOnLayerId IN(3,8,9,5)
option (recompile, querytraceon 8649)
else
select
[GeoServices_Location].[GeographicServicesGatewayId],
[GeoServices_Location].[Coordinate].Lat,
[GeoServices_Location].[Coordinate].Long
from GeoServices_Location with (index ([SPATIAL_GeoServices_Location]))
inner join GeoServices_GeographicServicesGateway
on GeoServices_Location.GeographicServicesGatewayId = GeoServices_GeographicServicesGateway.GeographicServicesGatewayId
where
GeoServices_Location.Coordinate.STIntersects(#viewport) = 1
and GeoServices_GeographicServicesGateway.PrimarilyFoundOnLayerId IN (3,8,9,5)
option (recompile, querytraceon 8649)
check the growth of the data/log files on the new server (DBs) vs old server (DBs) configuration: the DB the query is running on + tempdb
check the log for I/O buffer errors
check recovery model of the DB's - simple vs full/bulk
is this a consistent behavior? maybe a process is running during the execution?
regarding statistics/indexes - are you sure it's running on correct data sample? (look at the plan)
many more things can be checked/done - but there is not enough info in this question.

How to have sysdate result remoted across database link?

I'm running a query across a database link to a Sybase server from Oracle.
In it's where clause is a restriction on date, and I want it tied to sysdate, so something like this:
select * from some_remote_view where some_numeric_key = 1 and
some_date > sysdate+2
The problem is, when I do explain plan, only the condition some_numeric_key = 1 shows up in the actual sql that is getting remoted to the sybase server. Oracle is expecting to perform the date filter on its side.
This is causing a performance nightmare - I need that date filter remoted across to have this query working quickly
Even if I try something like casting the sysdate to a charcater string like this:
to_char(sysdate-2,'YYYY-MM-DD')
It still does not remote it.
Is there anything I can do to get Oracle to remote this date filter across the db link to Sybase?
Doing integration between Oracle and other platforms I often run into this problem, not just with SYSDATE but with other non-standard functions as well.
There are two methods to work around the issue, the first being the most reliable in my experience.
First, you can create a view on the remote db with the filters you need, then on the Oracle side you just select from the new view without additional filters.
Second, if you are not allowed to create objects on the remote side, try using bind variables (of the correct data type!) in your Oracle SELECT statement, e.g.:
declare
v_some_date constant date := sysdate + 2;
begin
insert into oracle_table (...)
select ...
from remote_table#db_link t
where t.some_numeric_key = 1
and t.some_date > v_some_date;
commit;
end;
/

Oracle accessing multiple databases

I'm using Oracle SQL Developer version 4.02.15.21.
I need to write a query that accesses multiple databases. All that I'm trying to do is get a list of all the IDs present in "TableX" (There is an instance of Table1 in each of these databases, but with different values) in each database and union all of the results together into one big list.
My problem comes with accessing more than 4 databases -- I get this error: ORA-02020: too many database links in use. I cannot change the INIT.ORA file's open_links maximum limit.
So I've tried dynamically opening/closing these links:
SELECT Local.PUID FROM TableX Local
UNION ALL
----
SELECT Xdb1.PUID FROM TableX#db1 Xdb1;
ALTER SESSION CLOSE DATABASE LINK db1
UNION ALL
----
SELECT Xdb2.PUID FROM TableX#db2 Xdb2;
ALTER SESSION CLOSE DATABASE LINK db2
UNION ALL
----
SELECT Xdb3.PUID FROM TableX#db3 Xdb3;
ALTER SESSION CLOSE DATABASE LINK db3
UNION ALL
----
SELECT Xdb4.PUID FROM TableX#db4 Xdb4;
ALTER SESSION CLOSE DATABASE LINK db4
UNION ALL
----
SELECT Xdb5.PUID FROM TableX#db5 Xdb5;
ALTER SESSION CLOSE DATABASE LINK db5
However this produces 'ORA-02081: database link is not open.' On whichever db is being closed out last.
Can someone please suggest an alternative or adjustment to the above?
Please provide a small sample of your suggestion with syntactically correct SQL if possible.
If you can't change the open_links setting, you cannot have a single query that selects from all the databases you want to query.
If your requirement is to query a large number of databases via database links, it seems highly reasonable to change the open_links setting. If you have one set of people telling you that you need to do X (query data from a large number of tables) and another set of people telling you that you cannot do X, it almost always makes sense to have those two sets of people talk and figure out which imperative wins.
If we can solve the problem without writing a single query, then you have options. You can write a bit of PL/SQL, for example, that selects the data from each table in turn and does something with it. Depending on the number of database links involved, it may make sense to write a loop that generates a dynamic SQL statement for each database link, executes the SQL, and then closes the database link.
If you want need to provide a user with the ability to run a single query that returns all the data, you can write a pipelined table function that implements this sort of loop with dynamic SQL and then let the user query the pipelined table function. This isn't really a single query that fetches the data from all the tables. But it is as close as you're likely to get without modifying the open_links limit.

Same stored procedure acts differently on two/(three) different IDEs

I just created a stored procedure in MS SQL DB using TOAD.
what it does is that it accepts an ID wherein some records are associated with, then it inserts those records to a table.
next part of the stored procedure is to use the ID input to search on the table where the items got inserted and then return it as the result set to the user just to confirm that the information got inserted.
IN TOAD, it does what is expected. It inserts date and returns information using just the stored procedure.
IN Oracle SQL developer however, it does the insert and it ends at that. It seems to not execute the 2nd part of the stored procedure which is a select stmt.
I just have a feeling that this is because of the jdbc adapter. Also why I'm asking is because I'm using a reporting tool Pentaho Report Designer and it would really make it easier if I can do 2 things at the same time. Pentaho Report Designer is also using jdbc adapters, not a coincidence maybe?
But if there are other things that I can tweak I'd really appreciate it.
This is a guess, but worth considering...
There are things called "Batches", where are sets of SQL Statements that are all sent to the server at once, and executed by the server as one set of statements, within a single server-side session. Sending a set of sql statements to the server as a batch will often result in different results than if you sent them one at a time, where each statement is executed in its own session.
I haven't used Toad (or Oracle) in a while, but as I recall, it dealt with batches differently than the other ide I used. If the second statement in your set is relying on being in the same session as the first, and in one ide it is in a separate session, then this might explain what is happening.

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