Here is the query to list object_id and object related informations using a below query. Once the table named tExample1 is created, an unique object_id will be assigned to the table object. Object_id would be the reference in most of the system views. Once the table is created, table related informations will immediately reflect in many system views like sys.objects, sys.indexes, sys.indexes, sys.columns etc. Lets examine that by creating a simple table (with record size less than 8000 and with no LOB data types). If record size of a table is less than 8000 and there is no LOB data type is present, all records are placed in IN_ROW_DATA pages. 16 byte pointer in data page will be used to refer LOB_DATA page. LOB data is stored in special pages called LOB_DATA pages. LOB_DATA : LOB data like text not stored along with data pages. In simple terms, ROW_OVERFLOW_DATA pages will come in to picture only when the row size exceed page maximum limit.ģ. Whenever user inserts a record with size greater than 8000 (page size is 8K), then the excess data is moved to ROW_OVERFLOW_DATA pages. ROW_OVERFLOW_DATA : assume that a table is created with record size 12000 bytes having 4 varchar data types of size 4000 bytes. IN_ROW_DATA (default) : If a table is relatively simple in desin (meaning record size is less than 8000 and no LOB data types are present), all records are stored in a pages refered as IN_ROW_DATA pages.Ģ. These page groups are in other term called allocation units.ĭifference among IN_ROW_DATA, ROW_OVERFLOW_DATA and LOB_DATA Pagesġ.
Whenever non clustered indexes are added, partitions are framed for each non clustered index and all index pages related to non clustered indexes are logically assigned to respective partitions.īased on data it holds, a partition can have 3 kind of page groups like IN_ROW_DATA pages, ROW_OVERFLOW_DATA pages and LOB_DATA Pages. Partition is a unit of data organization. When a table is created (Heap), by default all its pages are aligned in one partition. system_internals_allocation_units system views.Ĭase 1 (simple table with record size less than 8000 bytes and no LOB data) : Before moving on to see anatomy of different types of pages, lets spend some time to understand
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