1. Weird Stuff I Saw While ... Supporting a Java Team
Rick Lowe
@dataflowe

2. What I’m Not I am not a Java Expert I deny that I’m a developer
Probably not especially knowledgeable about using MSSQL from Java …
I am interested in starting a conversation about these issues
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10/10/2015
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3. Example 1 : Looking for the cache
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10/10/2015
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4. SelectMethod Options
“SelectMethod = full” : client retrieves entire result set
“SelectMethod = cursor” : server side cursor
“responseBuffering=adaptive” : Results retrieved as they are needed
Some are unaware of adaptive buffering.
Adaptive buffering is default in JDBC 2.0 and later
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10/10/2015
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5. Server Side Cursors Works much like a normal cursor
Cursor is created from a query and opened
Results are read back row-by-agonizing-row
Every single one of these steps involves a trip across the network
One row at a time minimizes memory requirements on the client
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10/10/2015
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6. Removing server side cursors
Not just annoying - potential performance issue
In recent JDBC versions, simply remove “SelectMethod=cursor” from URL
Evaluate on test system first
Workloads do exist where cursors are appropriate from a client side perspective
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10/10/2015
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7. Example 2 : Conversion to CRUD
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10/10/2015
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8. How things work in ADO.Net
try { mySqlCommand.executeUpdate(); } catch ….
executeUpdate() is not actually void, it returns # of rows imapacted.
… except we usually use NOCOUNT which means the return is always 0
And errors are more interesting than counts
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10/10/2015
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9. How things work in Java
PreparedStatement.executeUpdate() returns the number of rows impacted
… and it often actually gets paid attention to
When inserting, often check for return == 1
Quick fix is to remove “SET NOCOUNT ON” from Create stored procedures
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10/10/2015
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10. Example 3 : OUTPUT parameters
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10/10/2015
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11. It all seemed so easy…
PreparedStatement.executeUpdate() will not allow you to simply ignore parameters
PreparedStatement does not understand output parameters
Must use PreparedCall instead
To add confusion, there’s a new weird syntax you can use
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10/10/2015
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12. Windows Authentication
Doesn’t work.
Just kidding, it works. It just doesn’t work by default.
Setup depends on version
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10/10/2015
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13. Prior to JDBC 4
Copy sqljdbc_auth.dll from <jdbc>\sqljdbc_version\<language>\auth\<arch> to windows\system32
Be sure to grab the correct architecture – x86 vs x64
Then integratedSecurity=SSPI will work as expected.
Alternately, use the –Djava.library.path
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10/10/2015
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14. Starting With JDBC 4 Can still use sqljdbc_auth
Alternately, can use Java Kerberos
authenticationScheme=JavaKerberos
integratedSecurity=true
Must now specify FQDN for server name
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10/10/2015
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15. V1 Enterprise Java Beans
Enterprise Java Beans help encapsulate DB code
Developers implement methods to Create, Update, and Delete records
Called automatically as code works with objects
Issue with early versions – update method can be called whether or not data changes
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10/10/2015
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16. The Talk
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10/10/2015
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17. Query Hints In .Net shops, the NOLOCK wars rage on
Abusing hints is a bad habit …
… So we shouldn’t expect that getting folks to stop using NOLOCK just because we tell them the 101st time.
We usually settle for making our personal sandbox a “no smoking zone”
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10/10/2015
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18. Query Hints Contd.
Java people typically aren’t used to the Microsoft stack
This may be a new discussion for them
There is still room to change habits in this community
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10/10/2015
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