Table scan (TBSCAN) with partition pruning.
使用分区修剪的表扫描(TBSCAN)。
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。
The method may be a table scan , or may be scanning one or more indexes if they exist.
可能采用的方法包括扫描表和扫描一个或多个索引（如果有） 。
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。
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。
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。
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。
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。
Gather counts for base accesses (an index scan or a table scan of a table) that are not dependent on a join.
收集不依赖于连接(JOIN)的基本访问(表的索引扫描和表扫描)的计数。
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。
The preceding query requires MySQL to perform a full table scan, the slowest type of query for a large table.
上面的那个查询会执行一个全表扫描，对于一个大表来说这是最慢的一种查询方式。
The number of rows read (7700000) versus the number of rows written (77) show that a table scan is likely happening.
行读取的数目（77）表明很可能发生表扫描。
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。
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 predicates in the query in Listing 7 are weakly selective so that a full table scan of the PDBXML table is required.
清单7中查询的谓词选择性较弱，因此需要对pdbxml表进行全表扫描。
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。
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。
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。
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。
The plan shows a table scan over the aggregate_sales MQT. Moreover, the details of the operator table scan shows the following details.
该计划展示了aggregate_salesMQT上的一个表扫描。
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。
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。
Actually, a table scan of an in-memory table is much faster than searching the same table through an index, especially with the Informix light scan mechanism.
实际上，对内存中的表进行表扫描要比通过索引搜索同一表快得多，尤其是在使用 Informix轻型扫描机制时。
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。
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。
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。
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。
The earlier access plan shows that the total cost of the SELECT statement is 3420.41 timerons, which is from the table scan operator (TBSCAN) against the ACCOUNT table.
前面的访问计划显示select语句的总成本是3420.41timerons，这来自于表扫描操作符(TBSCAN)对ACCOUN t表进行的操作。
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。
Since Query 1 expresses the join predicate on the books table, DB2 9.1 and 9.5 perform a table scan on authors and then use the index AUTHORIDX1 to probe into the books table.
由于查询1表达了books表中的连接谓词，所以DB 2 9.1和9.5执行一个扫描authors的表，然后使用索引authoridx 1查找books表。
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