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11
votes
1answer
184 views

stats_column_id and index_column_id do not update with physical order of clustered index is changed

Unless I'm misunderstanding the purpose of the column, the following code indicates that a change of the structure of the clustered index does not change the ordinal position (stats_column_id)of the ...
9
votes
1answer
122 views

Why can my index seek estimate the right number of rows and the sort operator can't?

I've a query that uses a function on the predicate, something like this: commentType = 'EL' AND commentDateTime >= DATEADD(month,datediff(month,0,getdate()) - 13,0) I have a filtered index on ...
0
votes
1answer
26 views

Data impact on analyzing mysql table stats

I have a MySQL database that appears to be getting slower over time. After some googling, I determine that the database probably needs to be analyzed. This is because innodb_stats_on_metadata is set ...
18
votes
1answer
301 views

Statistics disappear after incremental update

We have a large partitioned SQL Server database utilizing incremental statistics. All of the indexes are partitioned aligned. When we try to rebuild a partition online by partition all of the ...
9
votes
1answer
141 views

Why does SQL Server refuse to update these statistics with anything but fullscan?

I noticed a relatively long running (20 min+) auto update statistics operation in a daily datawarehouse build. The table involved is CREATE TABLE [dbo].[factWebAnalytics]( [WebAnalyticsId] ...
6
votes
1answer
120 views

What is more appropriate sp_updatestats or UPDATE STATISTICS?

In a system there is a nightly data load process where all the foreign keys are dropped, all tables are truncated, repopulated from an external source, and the foreign keys are put back in place. At ...
0
votes
1answer
219 views

How to configure postgresql-9.2 to know blk_write_time in pg_stat_database

Interested in the procedure for collecting block write statistics of PostgreSQL 9.2. Steps followed for configuration, could get blk_read time but not blk_write_time CREATE EXTENSION adminpack; and ...
2
votes
1answer
563 views

Oracle 11g bug ? not returning the record until I triggered index to invisible and then to visible

We are using Oracle 11g, 11.2.0.3. We know a record exists in a table but a select is not returning it for some odd reason. The execution plans the general query, not forcing any index, shows that ...
0
votes
1answer
523 views

How to organize the tables of a MySQL database with several statistics data of several years?

I am developing an app that must provide statistics information about the distribution of the money that a person spends each year in taxes in the city where he lives. The user should select the ...
1
vote
3answers
56 views

What procedure can be used to change system statistics in a production environment

System statistics aren't required but highly recommended by Oracle. From my own experience, it produced a huge improvement on the total user IO waits of our production environment when first ...
3
votes
1answer
101 views

PostgreSQL + query planner + amount of entities

I'm working on a college assignment about how the query planner uses statistics and makes the most optimal query plan. I have read the 57.1. Row Estimation Examples article and I know how PostgreSQL ...
10
votes
2answers
5k views

Tracking stored procedure usage

Besides using SQL Server Profiler, is there any way to track which stored procedures are being used, or at least when they were last executed?
0
votes
0answers
38 views

Large differences between estimated and actual row counts but stats are OK

I'm having a problem with a Function which is taking 10 times longer to run than it used to and high CPU usage. And I'm puzzled by what I'm seeing in the execution plan with some index seek operators ...
1
vote
1answer
38 views

Understanding rows count computation

PostgreSQL 9.4 I have a table called customers which has a column income integer. After runnig ANALYZE against it I got the following statistic for the column: most_common_vals ...
2
votes
2answers
57 views

What parts make up pg_database_size?

I'm trying to write a munin plugin to graph DB sizes. Alongside using pg_database_size I want to graph the components thereof as well. So far, I've come up with the following: SELECT ...
26
votes
1answer
660 views

Is sys.stats_columns incorrect?

Let's say I have a table Foo with columns ID1, ID2 and a composite primary key defined over ID2, ID1. (I'm currently working with a System Center product that has several tables defined this way with ...
0
votes
0answers
33 views

Generate N x M random sample table from normal distribution in MySQL

Is there an easy way to produce a table of, say 10000 (rows) by 500 (columns) of numbers from normal distribution with parameters mu = 1, std.dev = 5 ?
3
votes
2answers
1k views

Which version of SQL Server 2016 supports R

Microsoft buying REvolution results (amongst other things) in the integration of R in SQL Server 2016. Looking through the features supported by the SQL Server 2016 I cannot find R-Support. Does ...
0
votes
1answer
60 views

Database modelling : Creating a model for restaurant application which gives statistics

I am working on a server-side application in which users will be able to give ratings and comments to different factors of a 'Restaurant'. What the webapp does is takes all the ratings and creates ...
19
votes
3answers
459 views

When is it better to create STATISTICS instead of creating an Index?

I have found plenty of information on what STATISTICS are: how they are maintained, how they can be created manually or automatically from queries or indexes, and so on. But, I have been unable to ...
0
votes
0answers
10 views

is there a way to see statistics on when and how often a view is being used in SQL Server? [duplicate]

I was recently handed a request to produce a report on all the views in a given database along with an indication of how frequently they are used, presumably so that the developers can remove views ...
3
votes
3answers
1k views

SQL Azure dm_exec_query_stats clearing?

I'm doing a lot of work with SQL Azure at the moment, trying to improve performance of a web app. I am using the dm_exec_query_stats view to look for poor performing queries. Does anyone know a way ...
0
votes
0answers
49 views

Is it good to gather stats in Oracle?

I have a very new database, and I have a request to gather stats for some schemas.. is it okay to gather stats without any transactions processed in the database? What are the impacts it could have if ...
2
votes
1answer
25 views

what monitor before applying changes on the server? - looking for a basic answer - starting point only

these settings were decision of our development team: there are 2 settings: 1 - max degree of parallelism 2 - optimize for ad hoc workloads On OUR_DEV_SERVER: 1. Run the following script: ...
6
votes
0answers
125 views

How to do Statistics in Partial Indexes of PostgreSQL efficiently?

This answer motivated think again my following tables but I am still uncertain how to store variables/results from data analysis for quick selection in post-processing. If stored, I think it is well ...
6
votes
1answer
119 views

PostgreSQL partial index unused when created on a table with existing data

In PostgreSQL 9.3, I am attempting to create an efficient index on a rarely-used (0.00001% of total records) boolean column. To that end, I discovered this post on SO: ...
1
vote
2answers
76 views

Partition of a table - how to minimize the time offline? How to check if all the statistics were updated?

As you ca see on the picture, I have a table called "tblsapdispatch" that has 55,707,259 records. Last sunday 30-aug-2015 they run a big update on this table, and I can see that the statistics were ...
0
votes
0answers
20 views

Howto avoid queries to get considered in statistics [duplicate]

Is it possible to run my (administrative) queries in a way that they do not get considered in Sql Server statistics like e.g. Cpu intensive queries, long running queries etc.? Is there an option like ...
7
votes
2answers
1k views

How to calculate cache misses for PostgreSQL

I'm administering a server where a tool using a PostgreSQL runs. The tool takes care of most PostgreSQL configurations by itself, but I'm observing some performance problems. I could confirm at OS ...
5
votes
1answer
192 views

Why is an additional filtered statistic being ignored (EAV schema)?

I'm trying to improve a row estimate for this sub-query (of a larger query). The estimate is showing 1266 rows. The actual is 117k rows. This particular property (EAV schema) only has two values ...
1
vote
2answers
53 views

Statistics that are neither auto_created nor user_created

So far, I was under the impression that there are two types of statistics objects in SQL Server: automatically-created statistics, which are created by SQL Server on index columns or single columns ...
1
vote
0answers
44 views

Oracle tuning strategy for columns with long tails

We have an Oracle 11g database, where the two biggest tables are Customer and Order. The order profile of our customers has a long tail: we have millions of customers, with most only having a small ...
3
votes
2answers
2k views

Executing the query “UPDATE STATISTICS [dbo].[Contact] WITH FULLSCAN …” failed

My maintenance plan fails with the following error on one of my databases does anyone know how I can fix this problem? is is a corrupt table? Executing the query UPDATE STATISTICS [dbo].[Contact] ...
13
votes
1answer
306 views

SQL Server recreating plans each day

We have this problem in our production environment. Microsoft SQL Server 2008 R2 (SP1) - 10.50.2500.0 (X64) - Enterprise Edition (64-bit) on Windows NT 6.1 (Build 7601: Service Pack 1). SQL Server ...
1
vote
1answer
42 views

Statistics needs to be captured for query analysis

What statistics are required to theoretically prove that X query work better than Y query. As per my knowledge I need to look for: Query elapsed time Logical read Logical write Physical read ...
1
vote
1answer
137 views

Does VACUUM FULL need ANALYZE

I'd be grateful for some insight into the VACUUM functionality within PostgreSQL 9.3. I read through the documentation and searched around a bit but could not find a definitive answer to this. I'm ...
1
vote
1answer
310 views

how to force oracle 12c to create histograms

I installed TPC-H on Oracle 12c and my goal is to get histograms on column groups (if anyone knows for sure that this is not possible anyway, please prove and I'll stop testing...). So I used select ...
1
vote
1answer
81 views

Count number of duplicate rows, sort from most to least (statistic) [closed]

I'm trying to make statistic of top-10 most visited URL. I have one simple table. For each URL visit, one row added with that URL as content. Most visited URL has the most number of duplicate. I've ...
9
votes
1answer
763 views

Should I disable “auto update statistics” in a data warehousing scenario?

I have 200 GB data warehouse in SQL Server. I have been experiencing really slow execution times for some queries; for example 12 hours for a simple delete query with an inner join. After doing ...
1
vote
1answer
43 views

SQL Server statistics

I have run the Database Tuning Advisor and it has suggested that some statistics are created. Whilst this is great and I understand the purpose of statistics, when I have reviewed them it has created ...
5
votes
1answer
641 views

Warning for missing statistics in execution plan

I have a situation that I cant understand. My SQL SERVER execution plan tells me that I have missing statistics on the table, but the statistics is already created. Please see the screens. But if ...
2
votes
1answer
335 views

How MySQL Queries and Questions status variables are calculated?

I have a mysql server running on 5.6.19 version and I got confused with the status variables Queries and Questions. show global status like 'Queries%'; | Queries | 28058738 | ...
5
votes
3answers
2k views

SQL Server - Varbinary Column - Extremely Slow Statistics Update

I have a table in my database that we use as a filestore, the file itself is stored in a varbinary column, which all seemed to work well until recently, we noticed one of our instances of this table ...
0
votes
0answers
60 views

Columnstore Index Scan Cardinality Estimates

In SQL Server 2012, I am seeing large cardinality estimate discrepancies for a columnstore index scan. It looks like statistics have been generated for the index, but I don't see any details in DBCC ...
3
votes
2answers
78 views

What happens with statistics when reverting to a database snapshot

Lets say I have a database FOO for which I created a snapshot (named FOO_snap). Now I'll run thousands of queries on this DB. After that I will revert DB to FOO_snap. Will I lose all of the statistics ...
3
votes
1answer
677 views

Get IO stats request sql like activity monitor

Is it possible to get the same value as in the activity monitor (SSMS) for the "Database IO" as a result of a SQL request? click to enlarge
0
votes
2answers
105 views

SQL storage sizing - How to get statistics of what data is being accessed

How can I monitor which data is being accessed and which frequency? I'm in need to migrate several (very) small SQL Server instances, each which several small databases. Current configuration is ...
3
votes
1answer
310 views

dbms_datapump API exclude statistics during import

We are using dbms_datapump to copy data between different servers or to setup new schemas quickly. However importing statistics usually takes ages and has the additional disadvantage that schema ...
18
votes
2answers
27k views

When To Update Statistics?

I've inherited a Maintenance Plans that does the following: Cleanup old data Checks DB integrity Performs Database and Transaction Log Backups Reorganizes Our indexes Updates Statistics Delete old ...
2
votes
1answer
75 views

Can statistics affect the query logic instead of performance?

Is it possible that the frequency of rebuilding indexes (which automatically triggers statistics update) can affect the query logic? One of the developers I work with claims that a stored procedure ...