When you run a query that references more than one table, HP Vertica may need to do one or both of the following operations to join the tables together: 1) Sort the data 2) Resegment the data
Local resegment groups are formed by resegmenting the data during the query execution with a node so that more parallelism can be exploited by each core can work on each of the small segment of the data.
Could you please explain for "LOCAL RESEGMENT GROUPS" and reason for joins in Plan with SQL involves one Table .
EXPLAIN SELECT COUNT(distinct customer_key) AS cntd_cust store_key,
COUNT(DISTINCT product_key) AS cntd_prod, COUNT(DISTINCT promotion_key) AS cntd_promo, SUM(sales_dollar_amount) AS sum_sales_dollar, SUM(cost_dollar_amount) AS sum_cost_dollar FROM store.store_sales_fact GROUP BY store_key ORDER BY cntd_cust DESC LIMIT 25;
Comments
When you run a query that references more than one table, HP Vertica may need to do one or both of the following operations to join the tables together:
1) Sort the data
2) Resegment the data
Local resegment groups are formed by resegmenting the data during the query execution with a node so that more parallelism can be exploited by each core can work on each of the small segment of the data.
I hope this answers your question.
Regards
Rahul
Could you please explain for "LOCAL RESEGMENT GROUPS" and reason for joins in Plan with SQL involves one Table .
EXPLAIN SELECT COUNT(distinct customer_key) AS cntd_cust store_key, https://my.vertica.com/docs/7.0.x/HTML/index.htm#Authoring/AdministratorsGuide/EXPLAIN/PartiallySort...