The index-statistics tag has no wiki summary.
2
votes
1answer
84 views
Query requires 'Update statistics' very often in SQL Server
We have a few tables in our database. Since most of our queries are date based, we have constructed clustered index on 'date + primary key (surrogate)' combination and we enforce joins on date as well ...
4
votes
1answer
65 views
Index Evaluation
I have been doing some index evalaution on a table and this is the first time I have ever looked at how well indexes are performing so and would like some advice on a certain index.
The non ...
0
votes
2answers
60 views
Indexing is not working
Following is the table and index information for which I have the queries at the end.
Create Table: CREATE TABLE `food` (
`id` int(10) unsigned NOT NULL DEFAULT '0',
`page_no` int(11) DEFAULT ...
3
votes
3answers
125 views
What is a good guideline for sampling for statistics updates
Scope: A billion record table that is indexed in 10 ways. Rate of change per day is 1/2 a percent.
Some of the indexes are monotonously increasing (datetime/timestamp), yet the common queries most ...
3
votes
1answer
182 views
Check Index Fragmentation on SQL Server Audit Queues
I've read this excellent article, http://rusanu.com/2010/03/09/dealing-with-large-queues/, and seem to be having the same issue, due to a low space issue, the service broker was turned off on a ...
3
votes
1answer
183 views
Difference between idx_tup_read and idx_tup_fetch on Postgres
On Postgres 8.4 when you do:
select * from pg_stat_all_indexes where relname = 'table_name';
It returns the fields idx_tup_read and idx_tup_fetch, what is the difference?
1
vote
1answer
171 views
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 ...
0
votes
0answers
289 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 ...
1
vote
2answers
96 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 ...
6
votes
3answers
3k 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 ...
7
votes
6answers
770 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
votes
1answer
140 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 ...
1
vote
2answers
187 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 ...
5
votes
3answers
2k 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.
