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Database Tuning

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Using the EXISTS Command in SQL
by Annem Jyothsna
Using EXISTS can improve the performance of your SQL queries.
Rebuild All Table Indexes in a SQL Server Database with One Command
by Srinath MS
An undocumented stored procedure lets you refresh all the table indexes in a SQL Server database with a single command.
Two Methods to Remove Duplicates in an ArrayList
by Vijayanandraj Amaladoss
Here are two methods that remove duplicates in an ArrayList.
Check for Duplicates in an ArrayList
by Vijayanandraj Amaladoss
Use this simple method to check for duplicates in an ArrayList.
Be Careful How You Name SQL Server Stored Procedures
by Andrew Holliday
When creating stored procedures in a database other then the Master database, avoid using the 'sp_' prefix. System stored procedures are the only ones that should use the 'sp_' prefix. The issue ...
Use WITH RECOMPILE Option for Dynamic Stored Procedures
by Andrew Holliday
When a stored procedure is first executed (and it does not have the WITH RECOMPILE option), it is optimized and a query plan is compiled and cached in SQL Server's buffer. If the same stored ...
Send Requests Via Stored Procedures
by Andrew Holliday
Whenever a client application needs to send Transact-SQL to SQL Server, send it in the form of a stored procedure instead of a script or dynamic Transact-SQL. This not only reduces network ...
Be Sure To Clear SQL Server Cache When Performing Benchmark Tests
by Andrew Holliday
When tuning SQL Server applications, a certain degree of hands-on experimenting must occur. Index options, table design, and locking options are items that can be modified to increase performance.
Watch Out For Orphan SQL Server Connections
by Andrew Holliday
Orphan SQL Server connections can decrease SQL Server performance. An orphan connection occurs when SQL Server keeps the connection open, even though it is not being used. There are two problems ...
Log Error
by DevX Pro
I am receiving this error in my log: connections rejected: no calls allowed for sqlexec. listener-thread err: = -27002 oserr: = 0 errstr = : No connections allowed in Dynamic server quiscent mode.
Informix Backups Error Message
by DevX Pro
We have Informix IDS 7.30 running under SCO 5.0.5. Backups by ontape fail with an error: "I/O read chunk 90, pagenum 2, pagecnt 1 --> errno = 9" But when we are doing normal queries, it's all fine. Any ideas?
Locking a Row
by DevX Pro
How can I lock a row in a table from a stored procedure?
Dropping a Bad Chunk
by DevX Pro
I have a bad chunk in a dbspace that is bad and marked "down" by Informix. I don't really care about the data in that chunk anyway, so I just want to drop it. But when I try to drop the chunk using "onspaces" it says I can't because it is "down". I don't want to do a restore of the whole database, and I would prefer not unload all the tables in the dbspace which this chunk resides in just to drop the entire dbspace, because that could take days. I believe Informix support can force the chunk to drop, but is there any way I can force the chunk to drop without going through Informix support?
Validation on Date Inputs
by DevX Pro
I'm using Web Datablade and IIF to develop Web pages. I need validation (other than JavaScript) on date inputs. How can I validate dates on IIF, using SPL or Web Datablade?
Committed Read Isolation Level
by DevX Pro
I've written several dynamic queries in VB importing a recordset from an Informix DB. The isolation level shows "Committed Read." Does this place locks on the DB?
NOW Function in Informix Hyperscript Tools
by DevX Pro
I am using Hyperscript Tools for Informix on a Unix platform. To receive the current date and time, the NOW() function is used to get a value between 0 and 401,768, each value representing a single day from the date Dec. 30, 1899. Unfortunately, this is returning a value of -657,186.48150463. Is this a known problem that has since been fixed or could it be a setup problem?
Queries Returning Empty Cursors on Informix
by DevX Pro
When in production (several users), my Web application starts getting empty cursors when querying the Informix server. I'm sure the 'right' results are not empty. Also, I've seen, using onmonitor, that accessing from the Web application I have two user threads tops. But I can't figure out how to correct this or what is limiting the access.
Temporary Table Creation
by DevX Pro
What is the advantage of creating temporary tables?
xp_cmdshell and Windows Apps
by DevX Pro
Why can't I run an application like ws-ftp from SQL with xp_xmdshell? ws-ftp will start, but it's not visible on the screen.
Asset Failed: Slot 1 Not Free in Page
by DevX Pro
My NT production system is down. Here's a breakdown: Update terminations, with error Inf -603, commit failed on table rfblg; RDBIF_SQL error on BSEG Running onchecks report BLOB Problems; error page; oncheck unable to correct database problem Attempted the following: 3.1 Reorganized/drop index of RFBLG 3.2 Unable to create index; error is BAD ISAM page Also unable to reorganized dbspace psapdn. Can I still salvage the database?
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