分析: 给定的sql查询在 idx_track_source_id_created_at_len_parse_result_list 索引上使用了索引查找。要判断是否还存在回表操作,需要检查 Extra 字段。 判断标准: 如果Extra 中包含usingIndex 或 Using Index Condition,则不需要回表。 如果Extra 中包含 Using where 且未出现
通过EXPLaiN 判断查询是否回表 要判断查询是否存在回表操作,可以使用 EXPLAIN 分析查询计划。以下是如何通过 EXPLAIN 输出的 Extra 字段判断: usingIndex:表示出现索引覆盖,查询所需的字段都在索引中,不需要回表。 Using Index Condition:表示使用了索引查找,但需要过滤,因为要过滤的字段不在索引中。不回表。 Using Inde...
Description: Suppose query_connection is executing a SQL with subquery, and stops at sync point BEFORE_RESET_QUERY_PLAN. Then we explain it in another explain_connection: ``` explain format=tree for connection <query_connection id>; ``` mysqld will crash: Assertion `current_thd->lex->using...
Even though volunteers and parents differed in several aspects regarding implementation, process features and tutor characteristics, these differences cannot explain the differential effects. The difficulty uncovering the components responsible for the efficacy of the method is discussed, and implications for ...
32 bit app - how to get 'C:\program files" directory using "Environment.GetFolderPath" 32 bit Application calling 32 bit DLL "An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)" 4 digit precision- String format 405 method not allowed(p...
And yes - I further believe you need to use the newer UEFI mode in order to allow boot from VHD. Older legacy MBR style boot method had no way of specifying a VHD file on an NTFS partition as a boot device I guess... You do not need to create or mount a VHD file... Once ...
induction of NEIs. In addition, they revealed the subtle effect of the infection method, e.g., RetroNectin versus spinoculation, on virus uptake in CD4-deficient cells (Supplementary Fig.12, see below). To assess whether the novel VOR complex-dependent pathway and the impact of drugs on it...
There's even a precedent in some of the papers PlasmaSphere listed: David Russell, a co-author of at least one of the 'Arp et al.' papers has no professional affiliation; if he can get stuff published, in mainstream astronomy journals, based upon research using those databases (and...
Method The study was co-led by an autistic researcher and a parent of an autistic person. Moreover, the study (hypothesis and terminology) was consulted with nonbinary autistic individuals. Preliminary analyses Non-binary participants, on average, scored higher on the AQ scale (M = 27.73; SD...
(473 out of 676) of the grid intersections were randomly selected for extended sampling. The extended sampling method followed [59]: for these selected grid intersections, one direction out of the eight possible directions (east, west, south, north, southeast, southwest, northwest, and northeast...