使用了连接缓存:Block Nested Loop,连接算法是块嵌套循环连接;Batched Key Access,连接算法是批量索引连接 Impossible where 该WHERE子句始终为false,不能选择任何行。 Select tables optimized away 在没有GROUP BY子句的情况下,基于索引优化MIN/MAX操作,或者对于MyISAM存储引擎优化COUNT(*)操作,不必等到执行阶段再进行...
1) Comma (,) as separator While declaration multiple variables and providing multiple arguments in a function, comma works as a separator. Example: int a,b,c; In this statement,comma is a separator and tells to the compiler that these (a, b, and c) are three different variables. 2) C...
(cost=103382.56 rows=1029632) -> Nested loop inner join (cost=409.36 rows=4022) -> Filter: (nation.N_NAME = 'IRAN') (cost=2.29 rows=3) -> Table scan on nation (cost=2.29 rows=25) -> Parallel index lookup on supplier using SUPPLIER_FK1 (S_NATIONKEY=nation.N_NATIONKEY), with ...
Using Loops in Programming In most of the programming languages, three looping structures 'for', 'while', and 'do-while' are used to perform the statements that need to be executed repetitively until a given condition is satisfied. For example, the 'for' loop can be implemented (in C) as...
In this case the leaves of the tree are implemented using a full table scans of the PRODUCTS and the SALES tables. The rows produced by these table scans will be consumed by the join operator. Here the join operator is a hash-join (other alternatives include nested-loop or sort-merge ...
C# Syntax: Breaking out of two nested foreach loops C# System.Configuration.ApplicationSettingsBase Mystery C# System.Drawing.Image and System.Drawing.Bitmap + (how to) Explicit Conversion + GetPixel C# System.OutOfMemoryException: 'Out of memory.' C# TCP Listener on External IP address - C...
For example, if the scan is the outer of a nested loop join). 'FAST' indicates that the scan is expected to progress with higher speed. This information is used to group scans together for efficient sharing of bufferpool records. SPILLED INTEGER Estimated number of pages in SORT spill. ...
This is how many blocks you processed in "consistent read" mode. This will include counts of blocks read from the rollback segment in order to roll back a block. This is the mode you read blocks in with a SELECT, for example. Also, when you do a searched UPDATE/DELETE, you read the...
28 1C BINARY(4) Format value. Used to highlight or format output data. For example, all header lines within the data attributes will have a format value associated with them. This identifies all the header records and allows users the option to format these specific records in the same man...
I could keep this section short by telling you that we have already seen an example for this: the function composition operator (.). It accepts two functions as arguments and returns a new one as in:squareAfterDouble :: Integer -> Integer squareAfterDouble = square . double...