Changes between Version 1 and Version 2 of BinarySearch

Timestamp:

May 6, 2010, 8:35:32 AM (15 years ago)

Author:

mmadia

Comment:

--

BinarySearch

@@ -6 +6 @@
 As you repeat this test, the range of possible revisions shrinks by half each time. To note, some version control systems such as hg and git call it 'bisect'. 
 
-Here is an example: revision 38000 fails to boot, last known good revision is 34000.
+Here is an example: revision 38000 fails to boot, last known good revision is 34000. That's a whopping 4,000 revisions to consider!
 
  1. Pass One
@@ -12 +12 @@
    * boot = success
    * the issue is somewhere between 36000 and 38000
-   * you eliminated 2,000 possible revisions
+   * you just eliminated 2,000 possible revisions with a single test!
  1. Pass Two
    * middle = 37000
    * boot = success
-   * the  is somewhere between 37000 and 38000
+   * the offending changeset is somewhere between 37000 and 38000
    * you eliminated another 1,000 possible revisions as not-containing the error.
  1. Pass Three
    * middle = 37500
    * boot = failure
-   * the  is somewhere between 37000 and 37500
+   * the problem is somewhere between 37000 and 37500
    * another 500 revisions (3,500 in total) are now known to be "good"
  1. Pass Four
    * middle = 37250
    * boot = success
-   * the  is somewhere between 37250 and 37500
+   * the error is somewhere between 37250 and 37500
    * Diminishing returns starts kicking in; only an extra 250 revisions were eliminated
  1. Pass Five
    * middle = 37375
    * boot = failure
-   * the  is somewhere between 37250 and 37375
-By testing 5 revisions, the range has been reduced from 4,000 to a more manageable 125!
+   * the issue is somewhere between 37250 and 37375
+
+By testing 5 revisions, the range has been reduced from 4,000 to a more manageable 125! If you wanted, you could keep repeating this to narrow the range to 63, 32, or even 16 revisions. Depending on the error and the neighboring commits, you may need to reduce it even further.