Questions tagged [index-statistics]

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Analyzing TCB Index Status for DB2

The Following is the TCB index that I could get using a command for my DB2 database. I don't know how to analyze it. Which columns are important? What do they mean? TCB Index Stats: Address ...
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0answers
1k views

Update Statistics Maintenance Plan - Ambiguous column name error

Microsoft SQL Server 2008 R2 Web Edition (RTM) - 10.50.1600.1 (Intel X86) Windows 2003 R2 SP2 I am in the process of setting up a maintenance plan to update statistics on a daily basis for all user ...
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2answers
236 views

How to retrieve the definition behind statistics added to tables

Is there a way to programmatically retrieve the definition of each STATISTICS added to table columns and indexes. For both user added and system created indexes. There are many STATISTICS like '...
12
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3answers
17k views

MySQL status variable Handler_read_rnd_next is growing a lot

In MYSQL status, Handler_read_rnd_next value is very high. I am aware that, this value will be incremented when a query is executed which is not having proper indexes. But, even when we execute ...
13
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7answers
7k views

Reasons for disabling statistics auto update?

I just learned that a client company I work for has decided to keep the auto update statistics options off for some of their SQL Servers, and the DBAs manually troubleshooting performance issues when ...
2
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1answer
175 views

Is this Index checking logic ok?

I am writing a script to quickly check the indexes in a given database. I think I have the script written ok but to remove duplicate rows I have done alot of SUM functions and I am unsure whether this ...
3
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2answers
303 views

dm_db_missing_index_details - does the order of equality_columns matter

I've been investigating some databases using the dm_db_missing_index_group_stats DMV, and have a question about the equality_columns field in the dm_db_missing_index_details view. MSDN says that this ...
16
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3answers
10k views

From where does the MySQL Query Optimizer read index statistics?

I'm trying to determine from where the MySQL optimizer obtains the list of indexes that are available for a table when it estimates the cost of (prepares) a query from.

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