Deduplicating at query time can be achieved by grouping the data on the fields, which uniquely identify a row, and using the argMax function with a date field to identify the last value for other fields. ReplacingMergeTree allows rows with the same sorting key (ORDER BY key) to be deduplicated on merges. Note this is "best effort" only: sometimes parts will not be merged with the merge process scheduled at non-deterministic intervals. It, therefore, does not guarantee the absence of duplicates. Users can also utilize the FINAL modifier to force this deduplication at SELECT time. While FINAL does add overhead, it has received significant performance improvements in recent versions including multi-threaded processing, and is suitable for many production workloads.
Deals on premium gaming mice do pop up pretty often, but it’s a lot less common to see one of Logitech’s flagship esports models sitting at a low price from two major retailers at the same time.
。雷电模拟器是该领域的重要参考
另一个窗户纸则是热效率。增程市场热衷于卷热效率这个纸面参数。友商动辄44%、45%的数据很唬人，但他们没告诉车主，这个“最高”往往只有一个点，只有在实验室那个特定的转速和负载下才能跑出漂亮数据，一旦脱离“最佳工况”，热效率就哗哗往下掉。有媒体把这形容为“一根缝衣线——窄得可怜”。
다카이치 “독도는 일본땅, 국제사회에 확실히 알리겠다” 망언