This hinders parallel scanning of data 從而延緩了數(shù)據(jù)的并行掃描。
Used to synchronize access to a range generator during parallel scans 用于同步在并行掃描期間對(duì)范圍生成器的訪問。
Used to synchronize access to read - ahead operations during key range parallel scans 用于同步在關(guān)鍵范圍并行掃描期間對(duì)預(yù)讀操作的訪問。
A table scan running on node n1 will only fill the memory associated with node n1 unless the scan is being run in parallel on cpus from multiple nodes 除非在cpu上對(duì)多個(gè)節(jié)點(diǎn)執(zhí)行并行掃描,否則,對(duì)節(jié)點(diǎn)n1執(zhí)行的表掃描僅填充與節(jié)點(diǎn)n1關(guān)聯(lián)的內(nèi)存。
If the tables are located on different servers , or on a computer that uses multiple processors , each table involved in the query can also be scanned in parallel 如果表位于不同服務(wù)器上,或者位于一臺(tái)使用多個(gè)處理器的計(jì)算機(jī)上,則還可以并行掃描該查詢所涉及的每個(gè)表。