Questions tagged [fragmentation]

Fragmentation exists when indexes have pages in which the logical ordering, based on the key value, does not match the physical ordering inside the data file.

Filter by
Sorted by
Tagged with
5
votes
3answers
505 views

How likely is fragmentation on a table with 40000 products likely to affect performance

So database administration is not a strong point of mine, so I have a few questions. This all relates to the performance of a website I'm looking at, and have spent a fair bit of time researching/...
0
votes
1answer
28 views

Not lowering avg fragmentation

I have a script which iterates through all database and underlying tables. With this script i want to rebuild/reorganize the indexes and i am testing this on AdventureWorks2017 database. So after ...
7
votes
1answer
214 views

Index fragmentation problem after disabling page-level locking for an Index

I have an Index which has page level locking disabled and now I have index fragmentation issues for that index. I was aware that I won't be able to Reorganize the index, but I believed that I would ...
4
votes
2answers
95 views

Indexes getting highly fragmented during normal usage of system

I am using MS SQL Server 2014 Standard Edition in my project and recently I have encountered an issue with index fragmentation getting high during normal usage of the system by the users. Currently ...
4
votes
1answer
88 views

Huge Heap Table and table compression on SQL Server 2016

My database size is huge, and recently I noticed that a new table added few months ago is the culprit. Here is the table script. SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo]....
1
vote
1answer
113 views

Is this database fragmentation or something else? What can be done?

I have the table below in PostgreSQL (automagically generated with insertions using Marten): create table mt_doc_order ( id uuid ...
1
vote
3answers
280 views

Query to see Index Fragmentation on all databases without using SP or temp tables

I am trying to compile a index fragmentation report on all databases, in a multi-server environment. The query will be executed via an openquery command, so I would like to make it as simple as ...
1
vote
1answer
46 views

Is there any way to find information of index fragmentation, Statistics information with the help of system tables in SQL Server

I am working on a report which will give information for different segments like blocking process slow running queries disk space etc. I also want to add one more segment where I can get ...
2
votes
1answer
235 views

Table Fragmentation

If I execute the following: SELECT dbschemas.[name] as 'Schema', dbtables.[name] as 'Table', dbindexes.[name] as 'Index', indexstats.alloc_unit_type_desc, indexstats.avg_fragmentation_in_percent as ...
2
votes
1answer
304 views

Fragmentation Level for Heaps

I am currently using scripts provided by Mr. Ola Hallengren for executing maintenance job and of-late I have been noticing that there are many tables (heaps) fragmentation level is alarmingly high and ...
0
votes
2answers
97 views

Will frequent creation and deletion of TABLE (not indexes) cause fragmentation in database?

Does frequent creation and deletion of physical table in database causes fragmentation? I am frequently creating and deleting database for loading data warehouse load. I am using these table to hold ...
0
votes
1answer
222 views

MariaDB defragmenting with new option innodb-defragment=1

I try to defragment table using innodb-defragment=1 https://mariadb.com/kb/en/library/defragmenting-innodb-tablespaces/ But it was a bad experience : - locks on table - no a good defragmentation ...
0
votes
1answer
81 views

use DBCC SHRINKDATABASE after rebuild / reindex [duplicate]

I have little free disk space. Why shouldn't you use DBCC SHRINKDATABASE (DBName, TRUNCATEONLY) after every rebuild/reindex operation?
3
votes
2answers
130 views

SQL Server one-to-many and index fragmentation

I'm currently writing code to update an entities child collection (one-to-many relationship), and while thinking about how to write code to determine which entities have been added/removed/modified, I ...
3
votes
3answers
6k views

Table and Index fragmentation

Is there any way to check whether a table or index has been fragmented? How to check if table is fragmented or not? How to check if index is fragmented? I searched Google but didn't get ...
0
votes
1answer
117 views

Index Maintenance - Reorganize After BIG SQL Server Shrink

I'm planning to execute the below index maintenance created by Ola Hallengren in a 1TB Database. EXECUTE [dbo].[IndexOptimize] @Databases = 'USER_DATABASES', @FragmentationLow = NULL, @...
1
vote
0answers
56 views

Fragmentation of indexes with small a database

I'm trying to figure out whether its worth defragging a 2GB mssql database. indexs are above 70% fragmented but queries don't appear to be talking too along. That being said I am having a delay when ...
2
votes
2answers
497 views

How to Limit DTU Percentage Consumption for a Given Session in Azure SQL Database?

We have an Azure SQL Database tier S4 (200 DTU), and there is one big table inside When I run a "alter index rebuild..." statement, it takes about 18 mins to complete This particular nonclustered ...
0
votes
2answers
79 views

Is Ola Hallengrens Stored Procedure what we need and safe to use [closed]

I stumbled across a stored procedure and wanted to clarify a few things first as I’ve been told it needs “rigorous review before being executed on any server”, and “testing before we run it on a ...
3
votes
1answer
264 views

Is high index fragmentation an issue on performance

Below is a small sample (top 20ish) from over 8000 indexes in avg_fragmentation_in_percent descending order. Will this cause any performance issues?
0
votes
1answer
287 views

Fragmentation in InnoDB tables: dump all data together reduced size, but fragmentation got worse

I have a question about tables and fragmentation in MySQL My starting point is this question: How find and fix fragmented MySQL tables I have a table with 1 million of rows and 128MB of space. This ...
1
vote
3answers
128 views

DataBase Performance Issues with Indexes

I'm reviewing a production database with over 400 tables and 658 indexes. I have determined that only 440 of these indexes are being used. Of these, many have fragmentation approaching 100% so I will ...
1
vote
2answers
256 views

Should I defragment InnoDB table with fixed-length fields?

I am running MariaDB 10.2.13 on Linux (Debian). I am setting up an InnoDB table that will record a lot of data but I will keep only the last one-hour rows. Thus, the number of rows will remain ...
0
votes
1answer
380 views

test data to generate high index fragmentation level

I want to test the rebuild and reorganize operations for the indexes in sql server and for that I need to populate the db with test data that generates high fragmentation levels/percentages. Does ...
2
votes
1answer
88 views

defragment SQL server database

I have deleted some tables on a SQL server. Suddenly the size of the database jumped by 100Gb (whereas the deleted tables were taking 10% of that..). I have read good and bad things about SHRINK ...
1
vote
1answer
2k views

Fragmentation in PostgreSQL 9.1

How can I check for fragmentation in PostgreSQL 9.1?
3
votes
1answer
1k views

Non-Unique Clustered Indexes Administration

I have been recently assigned to administer a database in SQL Server 2016 and I have discovered that there are many tables in the database with Non-Unique Clustered indexes resulting in Non-Clustered ...
5
votes
2answers
367 views

Determining what objects SHRINKDATABASE will free space from

First off, yes, shrink is bad. Don't use it, ever. I understand. Unfortunately, it's kind of SOP and I'm not in a position to argue since it's usually a stopgap until we can get a maintenance window ...
0
votes
1answer
750 views

MSSQL: High number of logical reads when inserting into fragmented heap

I'm inserting a batch of rows - using INSERT INTO tblUploadBanking SELECT FROM ... - into a table, which is a heap and have 3 narrow NC indexes. When I execute the query from SSMS with SET ...
2
votes
1answer
1k views

Is there a way to get index fragmentation without using dm_db_index_physical_stats? [duplicate]

I am using SQL Server 2016 SP1 standard edition. The view dm_db_index_physical_stats is very slow on big databases. Even if I specify the 'LIMITED' option. I use the view to get index fragmentation, ...
1
vote
0answers
142 views

Does disk fragmentation affect DB performance?

In one of the recent interviews I was asked DB question - There is a DB with ta table having million rows. Over time will it's performance degrade. Why and how? My answer was due to fragmentation (We ...
2
votes
2answers
533 views

Online & Offline Index Rebuild

I had this weird case today. Inside a database I had about 50 (1000+ pages, most of them 50000+ pages) tables which had their indexes fragmented above 70% even though I am running a nightly rebuild ...
2
votes
2answers
86 views

Are there any (functional or nuanced) differences between rebuilding an index and a full drop/create? If so, what are they?

I have been working on index fragmentation for indexes that are heavily used and causing performance decreases. Our standard job checks fragmentation levels and reorgs if >5% and <30%, and rebuilds ...
1
vote
0answers
328 views

Extreme high index fragmentation in MS SQL Server

I have a problem with CLUSTERED INDEX, every one of my table have extemely high total fragmentation, around 92% with having page fullness in the same time at around 99%. So in my understanding pages ...
4
votes
1answer
2k views

How can I *actually* defragment my InnoDB tables?

After a recommendation by mysqltuner I've run mysqlcheck --optimize --all-databases successfully (all of the tables reported "note : Table does not support optimize, doing recreate + analyze instead" ...
3
votes
1answer
994 views

Do we have to run auto update statistics after index rebuild?

I want to rebuild one of my indexes because fragmentation has reached 97 percent. I want to know if after I rebuild my index, do I have to update the statistics as well? My auto update statistics ...
0
votes
1answer
589 views

Distributed database for worldwide LIDAR point cloud [closed]

I have an idea for a project that would build a free worldwide 3D scan of the real world. You may think of it as a high-definition version of OpenStreetMap (OSM) project. The point cloud data would ...
1
vote
1answer
505 views

Index with high fragmentation percentage

I have a very large table with enormous percentage of index fragmentation( almost 98 % !). Obviously, it needs index rebuild. Main problem is my SQL Server is in Standard edition, thats why I cannot ...
1
vote
0answers
20 views

InnoDB: in what scenarios, if any, is it okay to have random insert WRT primary key?

For now let's ignore the benefits of having a surrogate key for business logic reasons. Let's only consider performance (speed and disk usage). CREATE TABLE `person` ( `ssn` bigint(20) unsigned NOT ...
1
vote
1answer
181 views

What is Heap Fragmentation sans Indexes?

When you talk about fragmentation in a heap that has no indexes, there can't be logical order fragmentation, so does fragmentation in this instance only refer to non-contiguous pages? Edit: no. Is ...
3
votes
2answers
572 views

SQL Server heap tables fragmentation monitoring

As a SQL Server DBA I have maintenance jobs to regularly rebuild/reorganize indexes. Recently, I ask myself about table fragmentation in SQL Server. Then I have read article regarding heap tables and ...
1
vote
1answer
97 views

Considerations for performance comparison with a high fragmented heap?

I am planning to perform some performance comparisons for different structures of one and the same table. The table I want to investigate on is a heap having ~ 1Mio rows and 123 columns. Setup: I ...
2
votes
3answers
622 views

Update statistics more often and stop defragmenting indexes

I have several vendor databases that have most (99%) of the tables clustered on GUIDs. Currently we are rebuilding the tables every weekend. Most tables are 80% or more fragmented by this time. ...
9
votes
1answer
10k views

How to lower HEAP Fragmentation in SQL Server?

i recently found out that one heap table had more than 70% fragmentation. So i decided to do a ALTER TABLE dbo.myTable REBUILD Funny enough, afterwards i had 20% fragmentation. There was no write ...
2
votes
2answers
2k views

Does Clustered Index on GUID create more fragmentation than Non Clustered Index?

I have a simple table: CREATE TABLE [dbo].[UserTestGroups]( [UserTestGroupId] [int] IDENTITY(1,1) NOT NULL, [Token] [nvarchar](100) NOT NULL, [TestId] [bigint] NOT NULL, [Group] [...
3
votes
1answer
778 views

What is the impact of temporarily setting ALLOW_PAGE_LOCKS ON

The MSDN ALTER INDEX page says "An index cannot be reorganized when ALLOW_PAGE_LOCKS is set to OFF." I'm modifying our index reorg/rebuild process to be sensitive to indexes that have ...
1
vote
1answer
352 views

Optimising file shrink and index reorganization operations

I'm archiving my SQL tables. So I am shrinking my files (because I need the free space) and re-organising my indexes(to defragment them). I know shrinking a file causes the indexes to be fragmented. ...
15
votes
2answers
3k views

Can SQL Server system tables be defragmented?

We have several databases in which a large number of tables are created and dropped. From what we can tell, SQL Server does not conduct any internal maintenance on the system base tables, meaning that ...
1
vote
1answer
116 views

Effect of logical fragmentation of range scan in SQL Server Table

To the best of my knowledge, this is what happens during a range scan of a table for some data when the table has got a clustered index: The lower range is first found out, traced to the leaf node ...
2
votes
4answers
5k views

Index fragmentation increased significantly after rebuild

I've googled this and I know that some people say index fragmentation doesn't matter, but they go on to describe scenarios where it might matter. Mine might be such a scenario. I have an index on a ...