WebMay 16, 2024 · The primary spool (the topmost operator in the plan) is fairly mundane. Like any other lazy spool, it reads each input row, inserts the row into the spool, and returns the row to the client. The secondary spool (below the nested loops join) is where all the interesting action is. Each time the nested loops join requests a row from the secondary ... WebJun 8, 2011 · Spooling doesn't have anything to do with your temporary tables. Spooling is effectively internal temporary tables used by the query planner. In fact it's quit e possible that if you use a few more summary temporary tables, it won't spool anymore. Wait... this was asked in 2009?! – Nick.McDermaid Mar 31, 2024 at 9:03 3
SQL Server Table Spool Operator (Lazy Spool) – Part2
WebOn the first execution, a lazy spool reads a row, counts it, and immediately returns an empty row for each read request. Subsequent executions return empty rows on each request up to the number of rows previously counted on the input, unless a rebind is issued. Consumer: Primary Node ID is present. WebJul 6, 2010 · The Row Count Spool operator is a simple component in an execution plan that can make an enormous difference to SQL query plans that would otherwise read a table on every row of the inner input to a nested loop. As this is a common type of query, it illustrates the power that a knowledge of your showplan operators can give you. central line introducer sheath
SQL Query Optimization: How to Tune Performance of SQL Queries
WebJan 7, 2014 · Even though Table Spool operator is shown in the execution plan multiple times, it is essential the same spool/cache. SQL Server builds it the first time and using its data later. Technically speaking, there are two different logical spool operators – Eager Spool and Lazy Spool.The only difference between them are how data is populated. WebDec 18, 2024 · 1 It's very hard to say what the problem is with just a plan and no real knowledge of the database. I'd also challenge that the problem is the lazy spool. One thing … WebAug 19, 2024 · Why are you worried about the lazy spool (I/O cost = 0.1)? It is more than 10,000 times cheaper than the sort (and is only there because of DISTINCT ). Have you … central line in right neck