clustered-index

问题 I am using SQL Server 2008. I know if a table has no clustered index, then it is called heap, or else the storage model is called clustered index (B-Tree). I want to learn more about what exactly means heap storage, what it looks like and whether it is organized as "heap" data structure (e.g. minimal heap, maximum heap). Any recommended readings? I want to more a bit more internals, but not too deep. :-) thanks in advance, George 回答1: Heap storage has nothing to do with these heaps. Heap just

问题 I have a quite huge existing partitioned table in bigquery. I want to make the table clustered, at least for the new partition. From the documentation: https://cloud.google.com/bigquery/docs/creating-clustered-tables, it is said that we are able to Creating a clustered table when you load data and I have tried to load a new partition using clustering fields: job_config.clustering_fields = ["event_type"] . The load finished successfully, however it seems that the new partition is not clustered

问题 I have a quite huge existing partitioned table in bigquery. I want to make the table clustered, at least for the new partition. From the documentation: https://cloud.google.com/bigquery/docs/creating-clustered-tables, it is said that we are able to Creating a clustered table when you load data and I have tried to load a new partition using clustering fields: job_config.clustering_fields = ["event_type"] . The load finished successfully, however it seems that the new partition is not clustered

问题 You can create a clustered index on a column other than primary key column if a nonclustered primary key constraint was specified. http://msdn.microsoft.com/en-us/library/ms186342.aspx So the above told me: I can create a clustered index on columns other than primary key. I think it also conveys that a primary key should either be a nonclustered primary key or clustered key. Is it possible a primary key is not indexed? What's more: When you create a UNIQUE constraint, a unique nonclustered

问题 I'm adding a new index to a SQL Azure database as recommended by the query insights blade in the Azure portal, which uses the ONLINE=ON flag. The SQL looks something like this: CREATE NONCLUSTERED INDEX [IX_MyIndex] ON [Customers].[Activities] ([CustomerId]) INCLUDE ([AccessBitmask], [ActivityCode], [DetailsJson], [OrderId], [OperationGuid], [PropertiesJson], [TimeStamp]) WITH (ONLINE = ON)" However, we also need to add this same index to our local development databases, which are just

问题 I'm adding a new index to a SQL Azure database as recommended by the query insights blade in the Azure portal, which uses the ONLINE=ON flag. The SQL looks something like this: CREATE NONCLUSTERED INDEX [IX_MyIndex] ON [Customers].[Activities] ([CustomerId]) INCLUDE ([AccessBitmask], [ActivityCode], [DetailsJson], [OrderId], [OperationGuid], [PropertiesJson], [TimeStamp]) WITH (ONLINE = ON)" However, we also need to add this same index to our local development databases, which are just

问题 I'm adding a new index to a SQL Azure database as recommended by the query insights blade in the Azure portal, which uses the ONLINE=ON flag. The SQL looks something like this: CREATE NONCLUSTERED INDEX [IX_MyIndex] ON [Customers].[Activities] ([CustomerId]) INCLUDE ([AccessBitmask], [ActivityCode], [DetailsJson], [OrderId], [OperationGuid], [PropertiesJson], [TimeStamp]) WITH (ONLINE = ON)" However, we also need to add this same index to our local development databases, which are just

来源： https://stackoverflow.com/questions/64287967/propagation-of-bigquery-parition-cluster-keys-to-a-cte-table-performance

来源： https://stackoverflow.com/questions/64287967/propagation-of-bigquery-parition-cluster-keys-to-a-cte-table-performance

问题 In MySQL, how can we tell if an index of a table is clustered or not? We can use show index from table-name to get information about the table's indexes. But I don't find it shows whether each index is clustered or nonclustered. This is for the purpose of If a table in MySQL has any index, must the table have a clustered index? 回答1: In the default storage engine, InnoDB, the PRIMARY KEY index is always the clustered index. If you don't have a PRIMARY KEY, it's the first UNIQUE KEY index on