| -> Limit: 100 row(s) (cost=14.62 rows=1) (actual time=1.252..1.252 rows=0 loops=1) -> Gather (merge sort; slice: 1; workers: 1; nodes: 2) (cost=14.62 rows=1) (actual time=1.250..1.250 rows=0 loops=1) -> Limit: 100 row(s) (cost=4.52 rows=1) (actual time=0.084,0....
Sort is used to sort data in ascending order (ASC) or descending order (DESC), which is usually used with the ORDER BY clause. In this example, data in the l_shipdate column of the TPC-H lineitem table is sorted. EXPLAIN SELECT l_shipdate FROM public.lineitem ORDER BY l_shipdat...
INSERT INTO users (name, email, password) VALUES ('张三', 'zhangsan@example.com', 'password123'), ('李四', 'lisi@example.com', 'password123'), ('王五', 'wangwu@example.com', 'password123'), ('赵六', 'zhaoli@example.com', 'password123'), ('钱七', 'qianqi@example.com', 'p...
If this columnis NULL, there are no relevant indexes. In this case, you may be able toimprove the performance of your query by examining the WHERE clause to checkwhether it refers to some column or columns that would be suitable forindexing. If so, create an appropriate index and check t...
Only 41 rows were returned (rows=41) but a sequential scan (Seq Scan on kvstore) was performed on all the rows (Storage Rows Scanned: 10000). Also, the data had to be sorted (viaSort Method: quicksort) on value (viaSort Key: value). You can improve this execution by modifying the...
In this case, you may be able to improve the performance of your query by examining the WHERE clause to check whether it refers to some column or columns that would be suitable for indexing. If so, create an appropriate index and check the query with EXPLAIN again. See Section 13.1.8, ...
In this case, you may be able to improve the performance of your query by examining the WHERE clause to check whether it refers to some column or columns that would be suitable for indexing. If so, create an appropriate index and check the query with EXPLAIN again. See Section 15.1.9, ...
The diagram below shows typical API designs with a shopping cart example. Note that API design is not just URL path design. Most of the time, we need to choose the proper resource names, identifiers, and path patterns. It is equally important to design proper HTTP header fields or to desi...
static void show_sort_keys(SortState *sortstate, List *ancestors, ExplainState *es);static void show_merge_append_keys(MergeAppendState *mstate, List *ancestors, ExplainState *es);static void show_agg_keys(AggState *astate, List *ancestors, ExplainState *es);static void show_grouping_sets...
(circa) 96-page manual around here actually all in English, if I search but it's likely something that came with a '90s operating system. Itself a climb-down from the... <hastilly grabs nearest suitable example> ...BBC Microcomputer manual which is a 500+ page (250+ leaf, if you ...