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 Using Index,则存在回表操作。 本例...
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...
In fact, it's not a bug that occurs only in debug builds. In release-builds, `explain format=tree for conn` at sync point BEFORE_RESET_QUERY_PLAN gives incorrect query plan. Take the same query in the test case as an example, the correct plan (from explain <query>) is: ``` ->...
In this post, I’ll outline what causes “err too many redirects,” how to troubleshoot the error, and, most importantly, how to fix it so you can get your site back up and running. Table of Contents Too Many Redirects Error How to Fix Too Ma...
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...
Personally I've always preferred to use Year-Month-Day my personal stuff. I like it because the format is written the way we write any other number: Most significant to left, least significant to right. I didn't know this was a standardized method and I've always wondered why it wasn'...
There is a meme (by Corona-is-hoax promoters and Communists-did-it-on-purpose proclaimers, mostly, so treat it with a pinch of salt rather than antivjral handwash) that doorknob-licking is a thing. Usually as a fabled method of infecting the doorknobs (by manchurin super-spreaders?) ra...
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...
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 ...
So, if you’ve got a problem with waking up in the morning and needing your two and a half cups of coffee to get going, you may want to try another method of getting ready for the day.“Caffeine stimulates your nervous system, which means too much can lead to a rapid heartbeat and...