CS411 - Query Processing2 Final Scribe

Buffer manager query execution plan page commands

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ur exploration of Relational and Non- relational. The figure depicts a fine grain model of query execution. If we were to run a query, then we follow the path shown: Query Execution User/ Application Query or update Query compiler Execution engine Record, index requests Read/write pages Index/record mgr. Buffer manager Query execution plan Page commands Storage manager storage 4 An SQL command goes into a query complier. This will be processed by the execution engine, which runs on every operator. The index then comes in to give you the appropriate value (B- tree, Hash etc are the index types we are referring to). Following that, they will come into the buffer manager. This is the virtual manager where it is decided what will come to the memory (This is the pin index to the memory). And finally, it goes to the storage manager that gets us the final output. Query is simply a structure of “lego” operators, thus all queries boil down to operators. Logical v.s. Physical Operators • Logical operators • what they do • e.g., union, selection, project, join, grouping Logical operators: has input and output. • Physical operators • how they do it • e.g., nested loop join, sort- merge join, hash join, index join Physical operator: defined by method Logical/Physical Operators: more info. 5 Given several building blocks, we get the alternative of having multiple ways of performing a task. This means that given a set of methods to perform a task, an optimal method may exist. The diagram to the left shows a breakdown of the query listed. Query...
View Full Document

Ask a homework question - tutors are online