scan table

基本解釋

For example if we want to know the gender ration in employee or customer pool, the bitmap index will help a lot without a full-table scan.
比如在雇員表的“性別”列上衹有“男”與“女”兩個不同值，因此就無必要建立索引。
For multiple index push-downs, multi-index scan is used to combine RIDs from different index scans, then skip-scan on the fact table is performed.
對於多索引下推，多索引掃描用於組郃來自不同索引掃描的 RID，然後就可以執(zhí)行對事實表的跳躍式掃描了。
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.
實際上，對內(nèi)存中的表進(jìn)行表掃描要比通過索引搜索同一表快得多，尤其是在使用 Informix 輕型掃描機(jī)制時。