Method of parallel trigger execution in an active database

Abstract

A method for executing after-triggers in an active database. A tree is constructed for each after-trigger and an operator tree is constructed for the statement that activates the trigger. The method joins each of the trees for the activated row-after triggers to the operator tree for pipelined execution with the operator tree. The trees for the activated row-after triggers form a group and each of the trees within the group execute in parallel with each other. The method joins trees for activated statement-after triggers to the operator tree for execution subsequent to the execution of the operator tree, the statement after trigger trees receiving rows from a temporary table that accumulates affected rows from the operator tree. Trees for activated statement after triggers form a group and each of the trees within the group execute in parallel with each other.

What is claimed is:  
     
         1 . A system, comprising: 
 a database manager coupled to a database, the data base manager: 
 joins a first trigger tree to an operator tree by interconnecting a flow operator between the first trigger tree and the operator tree; and  
 joins a second trigger tree to an operator tree by interconnecting a flow operator between a temporary table and the operator tree and interconnecting an ordered union operator between the flow operator and the second trigger tree.  
   
     
     
         2 . The system of  claim 1  wherein the temporary table stores rows of an input table that are affected by execution of an activating statement.  
     
     
         3 . The system of  claim 2  wherein the rows of the input table that are affected by execution of the activating statement are pipelined to a trigger associated with the first trigger tree.  
     
     
         4 . The system of  claim 1  wherein the database manager joins a plurality of trigger trees to an operator tree by connecting each tree to a parallel union operator and interconnecting a flow operator between the parallel union operator and the operator tree.  
     
     
         5 . The system of  claim 1  wherein the database manager joins a plurality of trigger trees to an operator tree by connecting each trigger tree to a parallel union operator, interconnecting an ordered union operator between the parallel union operator and a flow operator, and interconnecting the flow operator between the temporary table and the operator tree.  
     
     
         6 . A method, comprising: 
 executing a first type of triggers in parallel with each other;    pipelining the first type of triggers with an activating statement; and    executing a second type of triggers in parallel with each other and subsequent to the activating statement.    
     
     
         7 . The method of  claim 6  further comprising creating a temporary table, wherein the temporary table comprises rows of a input table that are affected by the activating statement.  
     
     
         8 . The method of  claim 7  further comprising providing the rows of the temporary table as input to the first type of triggers.  
     
     
         9 . The method of  claim 6  further comprising: 
 forming a plurality of execution plans associated with executing the first type of triggers, pipelining the first type of triggers with the activating statement, and executing the second type of triggers; and  
 evaluating the plans in terms of a performance metric.