Add estimateRowCount(), to support changes made in r21071

diff --git a/includes/DatabasePostgres.php b/includes/DatabasePostgres.php
index c280f48..6af0c02 100644 (file)
--- a/includes/DatabasePostgres.php
+++ b/includes/DatabasePostgres.php
@@ -558,6 +558,30 @@ class DatabasePostgres extends Database {
                return pg_affected_rows( $this->mLastResult );
        }
 
+       /**
+        * Estimate rows in dataset
+        * Returns estimated count, based on EXPLAIN output
+        * This is not necessarily an accurate estimate, so use sparingly
+        * Returns -1 if count cannot be found
+        * Takes same arguments as Database::select()
+        */
+       
+       function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
+               $options['EXPLAIN'] = true;
+               $res = $this->select( $table, $vars, $conds, $fname, $options );
+               $rows = -1;
+               if ( $res ) {
+                       $row = $this->fetchRow( $res );
+                       $count = array();
+                       if( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
+                               $rows = $count[1];
+                       }
+                       $this->freeResult($res);
+               }
+               return $rows;
+       }
+
+
        /**
         * Returns information about an index
         * If errors are explicitly ignored, returns NULL on failure