copr_cache_hit_ratio: 0.62, distsql_concurrency: 15} | data:TableFullScan_24 | 58.6 MB | N/A | | └─TableFullScan_24 | 90000.00 | 90000 | cop[tikv] | table:t2 | tikv_task:{proc max:31ms, min:0s, avg: 13ms, p80:19ms, p95:26ms, iters:181, tasks:24}, scan_detail: ...
sql="SELECT `L_ORDERKEY`, COUNT(*) AS `count(*)` FROM `lineitem` AS `lineitem` GROUP BY `L_ORDERKEY`"): rowcount =2508.0, cumulativecost=value=2.4860068E7, cpu =105038.0, memory =29796.0, io =201.0, net =4.75, id =109|
In static RAM, a form of flip flop holds each bit of memory. A flip-flop for a memory cell takes four or six transistors along with some wiring, but never has to be refreshed. This makes static RAM significantly faster than dynamic RAM. However, because it has more parts, a...
/* default behavior: look it up in the catalogs */ result = get_rel_name(indexId); if (result == NULL) elog(ERROR, "cache lookup failed for index %u", indexId); } return result;}/* * Show buffer usage details. */static voidshow_buffer_usage(ExplainState *es, const BufferUsage ...
copr_cache_hit_ratio:cop task 请求的 Coprocessor Cache 缓存命中率。Coprocessor Cache 配置。 rpc_info:按照向 TiKV 发送 RPC 请求的类型统计总数量和总时间。 backoff:包含不同类型的 backoff 以及等待总耗时。 Insert Insert 算子可能包含以下执行信息: ...
If the duration is long, the cache may not be hit. Create split reader cost: the duration that is taken to open a file. If the duration is long, the metadata of the file does not hit the cache. If this occurs, the I/O overhead is high. Get result cost: the duration from ...
In-memory package cache Package cache event monitor name The procedure searches for the section in the given location. An executable ID uniquely and consistently identifies a section. The executable ID is an opaque, binary token generated at the data server for each section that has been executed...
evaluated only once for each set of differentvalues of the variables from its outer context. For UNCACHEABLE SUBQUERY, thesubquery is re-evaluated for each row of the outer context. Cacheability ofsubqueries is subject to the restrictions detailed in Section 7.9.3.1, “How theQuery Cache ...
configure-memory-usage.md configure-placement-rules.md configure-store-limit.md configure-time-zone.md constraints.md control-execution-plan.md coprocessor-cache.md correlated-subquery-optimization.md cost-model.md credits.md daily-check.md data-type-date-and-time.md data-type-...
个人认为,项目上线,标志着一个项目真正的开始。从运维,到反馈,到再分析,再版本迭代,再优化… 这是一个漫长且考验耐心的过程。在这个过程中,作为数据存储的关键–>数据库的优化起到尤为重要的作用。 语文学的不好,废话也不多说,下面结合实例咱们说说MYSQL需要从哪些方面进行优化。