Date range queries going too slow for you? SQL Performance got you down? I have one weird trick that might just help you out! (SQL Developers hate this!)*

If you have a class that records timestamps when the data is added, then that data will be in sequence with your IDKEY values - that is, TimeStamp1 < TimeStamp2 if and only if ID1 < ID2 for all IDs and TimeStamp values in table - then you can use this knowledge to increase performance for queries against TimeStamp ranges. Consider the following table:

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Article
Peter Steiwer · Mar 2, 2020 2m read
SQL -99 error while viewing a listing

This error is sometimes seen while viewing a listing in InterSystems IRIS Business Intelligence:
ERROR #5540: SQLCODE: -99 Message: User <USERNAME> is not privileged for the operation (4)

As the error suggests, this is due to a permission error. To figure out which permissions are missing/needed, we can take a look at the SQL query that is generated. We will use a query from SAMPLES as an example.

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It has been noticed that some customers running JAVA programs (for example, FOP) on AIX would see the server eventually running low then out of memory. Customer would notice the system pages heavily and user experience becomes bad. And the server would crash when out of memory.

When the problem happens, we can see in ipcs a lot of shared memory segment marked for deletion (Capital D at the beginning of MODE section). This means they will not disappear until the last process attached to the segment detaches it.

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Article
Peter Everett · Sep 22, 2016 3m read
Windows write caching

(This article was reviewed in February 2021. It is still relevant to Caché-based installations and similarly applies to IRIS-based installations.)

This article discusses the Windows write caching setting which can leave systems vulnerable to data loss or corruption in the event of power loss or operating system crash. The setting is on by default in some Windows configurations.

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Article
Leo Makowski · Jul 15, 2016 5m read
Zinsert and friends: Coding in terminal

While Studio and Atelier are useful development interfaces, there are occasionally situations where a quick edit needs to be made to code and only terminal access is available. A useful set of tools to do this are the zload, zprint, zinsert, zremove, and zsave commands. These are abbreviated to zl, zp, zi, zr, and zs respectively. While each of these commands has its own page in documentation, this article will synthesize that information with examples to provide instruction for their combined use.

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Article
John Paladino · Dec 7, 2015 1m read
Welcome everyone!

I'm very proud of the Worldwide Response Center - an excellent group of men and women - and I am interested to hear from you about your experience using the WRC. There are always better ways for us to serve you.

I'm also very excited about the Developer Community which we're bringing to you to give you an opportunity to connect with groups and individuals in the InterSystems community. Let us know what you think and how we can improve it in order to serve you better.

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