These are just basic storage features we’re testing, so no concerns about using either of these. Both are hosted in the cloud.
Main translations that will be required for this session
The Page Splits/sec counter is one of the "piece of string" counters for which no absolute value should be assumed a breaking point for performance challenges. The counter can vary depending on table size, density, index depth, workload and workload type. Page Splits are an occurance on clustered indexes, which are an advanced feature for indexing as a whole and a standard feature for SQL Server.
A split happens, as shown here, when there isn’t enough room in a page and the data needs to write to the beginning of a new page. SQL Server needs to hold a latch for an extended period of time to alocate the new latch, copy data from the old page to the new page and then write the new data to the new page. SQL Server can also take additional latches on the intermediate index pages while in wait. This is the reason that rebuilds of indexes is still a common task in MSSQL. This is a higher latency wait when concurrency is added to the mix.
From the power dynamic mgmnt view, dm_db_index_usage, we can locate when there are indexes that are fragmented and impact performance in MSSQL.
Remember that Oracle leaves "dead" index nodes in the index when rows are deleted.
Create table, primary key on C1 to be populated by a sequence and trigger and index on C2
Create Sequence and Trigger to insert before each row.
Insert in 7 rows to fill up one block.
As expected, it’s now using 8 leaf blocks and is using only 1% to ensure that there is space left in each blog, (98%!)
Take care on large varchar2- only to 900 bytes. Now, does anyone know what the limit is on Oracle Varchar2 indexes? We’d use an Oracle Text index instead.
Insert 1 million rows
This is the first 8 rows from the initial test and the 1 million from the second test. Now delete rows where c2 includes the value of 200
With Different fillfactors on indexes
War of the Indices- SQL Server and Oracle
War of the Indices- SQL Server vs. Oracle
Index Power Between Platforms
Kellyn Pot’Vin-Gorman | Technical Intelligence Manager for the Office of CTO, Delphix