Questions tagged [heap]
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55 questions
3 votes
2 answers
551 views
Partitioning heaps - Why?
I know, at least theoretically, that heap tables can be partitioned. As I learn more about table partitioning, I realise that the use case is very limited. Similarly, the use case for heaps in SQL ...
- 1,322
2 votes
1 answer
110 views
Why same query is less performant on better machine?
Background I have two virtual machines set up on Azure: Standard E48ds v5 Standard E16ds v5 Both machines are running SQL Server 2019, and I have a specific query that retrieves data from a view. ...
- 487
3 votes
2 answers
553 views
Understanding pages in relation to heaps
I believe I am a little confused about what exactly a database page actually is, and perhaps also database heaps, and how they relate to each other. From my understanding; A database heap is a table ...
- 143
0 votes
1 answer
68 views
Are joins to heaps a performance concern if we can always force a hash join?
I clearly have a misconception, but no amount of consulting documentation has solved it. Consider the following argument: We generally worry about joining to heaps, because sorting them is often more ...
- 1,322
0 votes
1 answer
87 views
sys.indexes contains a row per index or heap of a tabular object - what does it mean?
I know a HEAP is a table without a clustered index. But I'm not quite clear on the following definition from sys.indexes. I understand that this system view contains row per index of a tabular object. ...
- 525
2 votes
1 answer
903 views
Does sql server lock entire table and keep it locked when the table is heap?
Irrespective of the where clause; When table is heap (no clustered indexes) then does a select query make sql server to lock all rows until it has finished reading all the rows? Where as in case of ...
- 3,602
5 votes
2 answers
1k views
What happens when you change a heap into a clustered table in SQL Server?
As I understand, a heap is an unordered object. When you insert a record, SQL Server use IAM page to get the pages that belong to this heap, and use PFS page to find a particular one which has enough ...
- 2,126
1 vote
0 answers
769 views
Understanding Heap Index in Postgresql
On Postgresql 12, given: postgres=# \d bip Table "public.bip" Column | Type | Collation | Nullable | Default --------+---------+-----------+----------+--------- a |...
- 591