full table scan中文，full table scan的意思，full table scan翻译及用法

2026-04-13 06:45 浏览次数 14

full table scan

Full table scan (also known as sequential scan) is a scan made on the database where each row of the table under scan is read in a sequential (serial) order and the columns encountered are checked for the validity of a condition. Full table scans are usually the slowest method of scanning a table due to the heavy amount of I/O reads and writes required from the disk which consists of multiple seeks as well as costly disk to memory transfers.

full table scan 例句

英汉例句

  • this report query requires a full table scan of the fact table.

    这个报表查询需要该事实表的一个全表扫描。

  • using an index for the former case is optimal while a full table scan for the latter case is optimal.

    前者使用索引更好，而后者则最好使用全表扫描。

  • currently, a full table scan is performed whenever runstats on table is run.

    目前，要运行表上的runstats，就要执行全表扫描。

  • the optimizer is more likely to choose a full table scan over an index if the value of this parameter is high.

    为什么设置高了，优化器会选择全表扫描而不选择索引？

  • 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。

  • this is a lot cheaper than a full table scan that reads every row.

    这远远低于全部表扫描（即读取每行）的开销。

  • if there is no index on name, the dbms does a full table scan and applies the toupper function on the name column for each tuple.

    如果没有为名称建立索引，那么dbms 将执行全表扫描并对每个元组（tuple）的name列应用toupper函数。

  • the benefit of system page-level sampling over a full table scan or bernoulli sampling is the savings in i/o.

    系统页级抽样优于全表扫描或贝努里（bernoulli）抽样的地方是它节省了i/o。

相关热词