Questions tagged [page-splits]
The process of splitting a physical storage page in two or more pages to accommodate new or changed rows.
Page split where existing rows are moved to different page occurs only for updates and non-sequential inserts?
Suppose page is full, and an item is inserted in order, then that item will get added to the next page. There will never be page split such that some rows are placed on a page and some rows move to ...
Updating rows in Azure SQL Server causing unexpected page splits
I'm getting a lot of page splits in a live environment using Azure SQL Server PAAS that I don't understand. The update that's occurring should not increase the size of the row and therefore never ...
Can lowering fill factor result in more page splits? [closed]
We've been having a problem with page splits on a table that is a particular nuisance - its an audit log of activities in the database and has grown over 1TB. The main indexes are on the record type, ...
How to find if my innodb row uses overflow/off pages?
I use INNODB engine. My row format is Dynamic. For variable-length columns like TEXT, BLOB and varchar etc. , data is stored in off page and not in the same page itself. Do I have a way to ...
Need some insights on 'index_page' variables in Innodb_Metrics Table
I was experimenting with page-split behaviour for sequencial vs random ordered inserts in Mysql,Innodb. For sequencial Inserts I got: index_page_splits: 3199 index_page_merge_attempts: 0 ...
How are page splits determined internally in MySQL?
Going through this answer for a stack-overflow question, I found a fact that In The physical structure of InnoDB index pages I describe the Last Insert Position, Page Direction, and Number of ...
Can an InnoDB page contain data from different indexes?
(In this question, I assume that the data of a table is acťually an index (PRIMARY), so I don't differentiate between table data and column indexes) I've compacted an "old" InnoDB table (via null ...
Page splits on an empty table
I have a monitoring tool that alerted me to high page splits, 50% of new allocations. I found the following query to look and see: SELECT IOS.index_id, O.NAME AS ...
MSSQL Page Split Spike on AlwaysOn Readable Secondary
Recently I caught a massive page-split spike on an AlwaysOn Secondary instance that was not mimicked in any way by the active primary. I'm interested in what might cause this on a readable secondary ...
Is it possible to get a "pages touched" statistic from PostgreSQL?
With PostgreSQL one can measure disk reads and cache hits. Is it possible to have a clearer statistic of how many index pages were "touched" to run a query? If so, how?
Finding reason for page splits
So normally we have 20-85 Page splits/s but sometimes this spikes up the 700 - 2500 range. So to figure out what was happening i created a Extended Event with the following: CREATE EVENT SESSION ...
Index Pages (page type 2)
I trying to understand page splits in SQL Server, reading WHAT IS A PAGE SPLIT? WHAT HAPPENS? WHY DOES IT HAPPEN? WHY WORRY? by Tony Rogerson CREATE TABLE mytest ( something_to_see_in_data CHAR(...
MS SQL Page split confusion
I am a bit confused about page splits in MS SQL and I'm looking for a definitive answer. There seem to be two versions of the story: 1 - Fillfactor only affects how full pages are at the time the ...
Is there a way to track page splits on an InnoDB table?
Is there a way to track the number of page splits on an InnoDB table? I've inherited a couple high-volume tables with integer primary keys in which values are often inserted out of order and I'd like ...
Refactoring 80 GB table that stores massive amount of calculated results
Trying to evaluate architectural changes to improve the performance of an app that calculates a lot of individual values and stores each of these results as a row. The storage size for one of the ...
Merits of inserting to temp table and renaming versus just adding/removing columns
If I add or drop columns from a SQL Server table I presume I get page splits or gaps. Since the size of the row has changed. When I use RedGate SQL Compare to create conversion scripts its strategy ...
SQL Server 2000 Page Splits per second higher han 12 million?
I was reading about index fill factors & performance, and out on a whim I tried the query given by the webpage on the company's production SQL Server 2000 server: SELECT * FROM MASTER.dbo....
Analyse what caused a pagesplit afterwards?
Ok normally we have 0-20 page splits per second, but last night it spiked to ~500. Now is there any way to figure out what caused it? I know i can run the following to find mid page splits but it ...
Why only 8kb per page?
I just want to know how they came to 8kb when striking a balance between: smaller page = more page splits bigger page = longer to look through to find value I expect there are many more pros and cons ...
Page Break is splitting in the middle of a single row in SSRS
I have an SSRS report for an Invoice and it generally works perfectly but occasionally it will page break in the middle of a row in the main Tablix. The row will split and leave part of the text on ...
Page Split Timing
So, imagine I have a page that I intend to cause to split. USE master ; GO IF DATABASEPROPERTYEX (N'Pages', N'Version') > 0 BEGIN ALTER DATABASE Pages SET SINGLE_USER WITH ROLLBACK IMMEDIATE; ...
B-tree node split strategy in SQL Server for monotonically increasing value
Consider a B-tree index on a value that will always increase monotonically, e.g. a column of type IDENTITY. With a conventional B-tree implementation, whenever a node is full, it will be split 50%/50% ...