Package org.intermine.sql.query

Class ExplainResult

  • Direct Known Subclasses:
    DummyExplainResult, PostgresExplainResult
    public class ExplainResult
extends java.lang.Object
    Represents a result from an EXPLAIN request to a database.
    Author:
    Matthew Wakeling, Andrew Varley

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected long complete  
      protected long estimatedRows  
      protected long rows  
      protected long start  
      protected long width  

    • Constructor Summary

      Constructors 
      Constructor Description
      ExplainResult()  

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean equals​(java.lang.Object o)
      long getComplete()
      Returns the number of page requests before the query is completed, estimated by the database for this query.
      long getEstimatedRows()
      Returns the best current estimate for the number of rows for this query.
      static ExplainResult getInstance​(java.lang.String query, java.sql.Connection database)
      Constructs an instance of ExplainResult for a given query String and database Connection.
      static ExplainResult getInstance​(java.sql.PreparedStatement stmt)
      Constructs an instance of ExplainResult given a PreparedStatement object.
      static ExplainResult getInstance​(Query query, java.sql.Connection database)
      Constructs an instance of ExplainResult for a given Query and database Connection.
      long getRows()
      Returns the number of rows estimated by the database for this query.
      long getStart()
      Returns the number of page requests before the first row is returned, estimated by the database for this query.
      long getTime()
      Returns an estimate of the time it will take to complete the query.
      long getWidth()
      Returns the width of the data returned by the database for this query.
      int hashCode()
      void setEstimatedRows​(long estimatedRows)
      Use this to provide the object with a "better" estimate of the number of rows in the results of this Query.
      java.lang.String toString()

      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    • Field Detail

      • rows

        protected long rows

      • start

        protected long start

      • complete

        protected long complete

      • width

        protected long width

      • estimatedRows

        protected long estimatedRows

    • Constructor Detail

      • ExplainResult

        public ExplainResult()

    • Method Detail

      • getInstance

        public static ExplainResult getInstance​(java.lang.String query,
                                        java.sql.Connection database)
                                 throws java.sql.SQLException
        Constructs an instance of ExplainResult for a given query String and database Connection.
        Parameters:
        query - the String query to be explained. It need not start with "EXPLAIN"
        database - a java.sql.Connection by which to access the database. The particular subclass of ExplainResult returned depends on the type of this Connection
        Returns:
        an instance of ExplainResult
        Throws:
        java.sql.SQLException - if the query cannot be explained by that database

      • getInstance

        public static ExplainResult getInstance​(Query query,
                                        java.sql.Connection database)
                                 throws java.sql.SQLException
        Constructs an instance of ExplainResult for a given Query and database Connection.
        Parameters:
        query - the org.intermine.sql.query.Query to be explained
        database - a java.sql.Connection by which to access the database. The particular subclass of ExplainResult returned depends on the type of this Connection
        Returns:
        an instance of ExplainResult
        Throws:
        java.sql.SQLException - if the query cannot be explained by that database

      • getInstance

        public static ExplainResult getInstance​(java.sql.PreparedStatement stmt)
                                 throws java.sql.SQLException
        Constructs an instance of ExplainResult given a PreparedStatement object. Assumes that sql string already has EXPLAIN at beginning
        Parameters:
        stmt - the PreparedStatement to be explained
        Returns:
        an instance of ExplainResult
        Throws:
        java.sql.SQLException - if the query cannot be explained by that database

      • getRows

        public long getRows()
        Returns the number of rows estimated by the database for this query.
        Returns:
        estimated number of rows

      • getStart

        public long getStart()
        Returns the number of page requests before the first row is returned, estimated by the database for this query.
        Returns:
        estimated number page requests before the first row

      • getComplete

        public long getComplete()
        Returns the number of page requests before the query is completed, estimated by the database for this query.
        Returns:
        estimated number page requests before query completion

      • getWidth

        public long getWidth()
        Returns the width of the data returned by the database for this query.
        Returns:
        width in characters

      • setEstimatedRows

        public void setEstimatedRows​(long estimatedRows)
        Use this to provide the object with a "better" estimate of the number of rows in the results of this Query.
        Parameters:
        estimatedRows - the better estimate, in rows

      • getEstimatedRows

        public long getEstimatedRows()
        Returns the best current estimate for the number of rows for this query.
        Returns:
        estimated number of rows

      • getTime

        public long getTime()
        Returns an estimate of the time it will take to complete the query. The estimate is based on information from the EXPLAIN database call, and possibly a better estimate of how many rows will be returned.
        Returns:
        estimate of time in milliseconds

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • equals

        public boolean equals​(java.lang.Object o)
        Overrides:
        equals in class java.lang.Object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object