Table 2 summarizes how the performance of this table scan query has benefited from two of our design decisions: atom site separation and compression.
表2总结了此次表扫描的性能如何能从我们的两个设计决策中受益：原子站点分离和压缩。
Deterministic function calls can be extracted from the WHERE clause to avoid unnecessary table scan.
可以从WHERE子句中提取确定性函数调用，避免不必要的表扫描。
It looks like we are doing a sequential scan (of an entire table) to satisfy the SQL command, whatever it is.
好像我们正在进行顺序扫描(对整个表)来满足SQL命令的需求，不管它是什么。
When DB2 performs an index or table scan, DB2 will block on a row lock when it comes across an uncommitted row which another transaction has exclusively (X) locked.
DB2在执行索引或表扫描时，如果遇到一个被另一个事务独占 (X) 锁定的未提交行，那么 DB2将阻塞在行锁上。
Thus, DB2 cannot use those indexes and resorts to a table scan to ensure a correct query result.
因此，DB 2不能使用那些索引，而是会采取表扫描来确保正确的查询结果。
Most often, you want only a small subset of the data in the table, so a full table scan wastes a lot of disk I/O and therefore time.
通常来说，您可能只希望获得表中数据的一个子集，因此全表扫描会浪费大量的磁盘I/O，因此也就会浪费大量时间。
If the table in your query are pretty small (usually fewer than 1,000 rows) or clustered tables, and your query is not selective at all, it would be beneficial to use a table scan.
如果查询中的表极其小(通常少于1,000行)或者是群集表，而且查询根本没有选择性的话，那么使用表扫描会更好一些。
Since only one row is expected in the result set from this SELECT statement, the table scan here is considered an expensive operation.
因为该select语句的结果集中只期望一行，所以表扫描在这里被认为是代价较高的操作。
Therefore, when deciding which join method to choose, the optimizer balances the sort cost and the performance benefit for the inner table scan to drive the decision.
因此，在决定选择哪种联接方法时，优化器为内部表扫描平衡排序成本和性能优势以便促进决策。
Basically, it's weighing the choice of using the index to walk through the selected rows or doing a table scan.
基本上，它会权衡使用索引来遍历选择的行或者对表进行扫描这两种方式。
We found a bigger difference for queries that touch a large number of rows, such as a table scan over all 20,000 XML documents with string comparison on every document.
我们发现涉及大量行的查询的性能差异比较大，比如对所有20,000个XML文档进行全表扫描并对每个文档比较字符串。
This guideline specifies that a single XML index scan be used to access the given table.
该准则指定一个单一的xml索引扫描，将用于访问给定的表。
Then for each row from the fact table scan, the foreign key is also hashed and probed into the bit vector to determine whether the current fact table row is filtered out.
然后针对事实表扫描的每一行，外键也被散列并探测到位向量中，从而判断当前的事实表行是否被过滤掉了。
The simplest way is to read the table's data sequentially, performing a table scan as we usually call it.
最简单的方法是连续读取表中的数据，就是按照我们通常调用它的方法来执行表扫描。
The optimizer, in the absence of current statistics, is choosing to do a table scan on both tables involved in the join.
在缺少当前统计的情况下，优化器选择对参与联接的两个表进行表扫描。
The optimizer normally chooses a table scan if no appropriate index has been created or if an index scan would be more costly.
如果没有创建合适的索引，或者如果索引扫描的成本更高一些，优化器通常就选择表扫描。
If a table scan is used, the clustering would not really be beneficial because DB2 still has to read all rows and then the physical ordering is not very important.
如果使用表扫描，那么聚集就不会真正有益，因为DB 2仍然必须读取所有的行，那么物理排序不很重要了。
Indexes improve query performance by avoiding a full table scan.
索引能够避免全表扫描，从而能够提高查询性能。
However since it is a leading table and will be accessed by the table scan only once, it may cause some performance problems, but it should not be a disaster.
尽管如此，由于它是主表，而且只用表扫描访问一次，因此会引发一些性能问题，但不会太严重。
What is wrong with the bills table that the optimizer thinks it should sequentially scan the entire table?
账单表出了什么问题，使得优化程序认为需要顺序扫描整个表？
XSCAN is not an "XML table scan" but it can appear in an execution plan after a table scan to process each of the documents.
XSCAN不是 “XML表扫描”，但在表扫描之后，它可以出现在执行计划中，用来处理每个文档。
This means that a sequential scan of the table will be faster than an indexed read, and we cannot play with the filter criteria.
这意味着对表的顺序扫描比索引读取更快，我们无法遵循指示器标准。
The number of rows selected from each dimension table is less than the number of rows selected from the fact table after all scan filters are applied.
所有的扫描过滤器都应用后，每个维度表选出的行数少于事实表选出的行数。
Limited partition scan is a method that allows DB2 to limit the scan of data in a partitioned table space.
限定分区扫描允许DB 2将数据扫描限制在一个分区表空间中。
The outer table can be accessed by an index scan or by a table scan, depending on the table.
通过索引扫描还是表扫描来访问外部表则取决于该表。
Since there is no COMMIT between the INSERT and SELECT statement, potentially the deadlock is caused by a table scan.
由于INSERT和select语句之间没有COMMIT，死锁可能是由表扫描引起的。
Table scan (TBSCAN) with partition pruning.
使用分区修剪的表扫描(TBSCAN)。
If there is no index on ucname, the DBMS still does a full table scan, but it need not do any further processing on the data to determine whether or not it satisfies the query.
如果没有为ucname创建索引，DBMS仍然执行全表扫描，但是不会对数据进行进一步处理来判断其是否满足查询。
In this case, a table scan is very expensive, because the Informix engine has to access data randomly.
该例中，表扫描极其昂贵，因为Informix引擎必须随机地访问数据。
Next, contestants needed to add appropriate indexes to each table, so that Informix would not scan the whole table to find the row it needed to update.
接下来，参赛者需要向每个表添加合适的索引，以便Informix无需扫描整个表即可找到它需要更新的行。
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