fixing deadlock issue in chainmaven

[Mike McLean]

This patch works around a deadlock issue that can occasionally happen
with chainmaven builds if the hub is using an older version of postgres.

[PATCH] Avoid multiple updates to same rows in taskSetWait

[Mike McLean]

Instead of broadly clearing data by calling taskUnwait, only update the rows we need to.
Also, use UpdateProcessor in taskSetWait and taskUnwait
---
 hub/kojihub.py | 49 +++++++++++++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 20 deletions(-)

diff --git a/hub/kojihub.py b/hub/kojihub.py
index f076f02..4dc2bcf 100644
--- a/hub/kojihub.py
+++ b/hub/kojihub.py
@@ -9742,33 +9742,42 @@ class Host(object):
             raise koji.AuthError, "This method requires an exclusive session"
         return True

-    def taskUnwait(self,parent):
+    def taskUnwait(self, parent):
         """Clear wait data for task"""
-        c = context.cnx.cursor()
         #unwait the task
-        q = """UPDATE task SET waiting='false' WHERE id = %(parent)s"""
-        context.commit_pending = True
-        c.execute(q,locals())
+        update = UpdateProcessor('task', clauses=['id=%(parent)s'], values=locals())
+        update.set(waiting=False)
+        update.execute()
         #...and un-await its subtasks
-        q = """UPDATE task SET awaited='false' WHERE parent=%(parent)s"""
-        c.execute(q,locals())
+        update = UpdateProcessor('task', clauses=['parent=%(parent)s'], values=locals())
+        update.set(awaited=False)
+        update.execute()

-    def taskSetWait(self,parent,tasks):
+    def taskSetWait(self, parent, tasks):
         """Mark task waiting and subtasks awaited"""
-        self.taskUnwait(parent)
-        c = context.cnx.cursor()
-        #mark tasks awaited
-        q = """UPDATE task SET waiting='true' WHERE id=%(parent)s"""
-        context.commit_pending = True
-        c.execute(q,locals())
+
+        # mark parent as waiting
+        update = UpdateProcessor('task', clauses=['id=%(parent)s'], values=locals())
+        update.set(waiting=True)
+        update.execute()
+
+        # mark children awaited
         if tasks is None:
-            #wait on all subtasks
-            q = """UPDATE task SET awaited='true' WHERE parent=%(parent)s"""
-            c.execute(q,locals())
+            # wait on all subtasks
+            update = UpdateProcessor('task', clauses=['parent=%(parent)s'], values=locals())
+            update.set(awaited=True)
+            update.execute()
         else:
-            for id in tasks:
-                q = """UPDATE task SET awaited='true' WHERE id=%(id)s"""
-                c.execute(q,locals())
+            # wait on specified subtasks
+            update = UpdateProcessor('task', clauses=['id IN %(tasks)s', 'parent=%(parent)s'], values=locals())
+            update.set(awaited=True)
+            update.execute()
+            # clear awaited flag on any other child tasks
+            update = UpdateProcessor('task', values=locals(),
+                            clauses=['id NOT IN %(tasks)s', 'parent=%(parent)s', 'awaited=true'])
+            update.set(awaited=False)
+            update.execute()
+

def taskWaitCheck(self,parent):
         """Return status of awaited subtask

[Peter Robinson]

On Thu, Oct 8, 2015 at 7:56 PM, Mike McLean  wrote:
> This patch works around a deadlock issue that can occasionally happen
> with chainmaven builds if the hub is using an older version of postgres.

I think the patch is missing

[PATCH] Avoid multiple updates to same rows in taskSetWait

[Mike Bonnet]

On 10/8/15 2:56 PM, Mike McLean wrote:
> Instead of broadly clearing data by calling taskUnwait, only update the rows we need to.
> Also, use UpdateProcessor in taskSetWait and taskUnwait

Looks good to me, +1.
> hub/kojihub.py | 49 +++++++++++++++++++++++++++++--------------------
>   1 file changed, 29 insertions(+), 20 deletions(-)
>
> diff --git a/hub/kojihub.py b/hub/kojihub.py
> index f076f02..4dc2bcf 100644
> --- a/hub/kojihub.py
> +++ b/hub/kojihub.py
> @@ -9742,33 +9742,42 @@ class Host(object):
>               raise koji.AuthError, "This method requires an exclusive session"
>           return True
> def taskUnwait(self,parent):
> def taskUnwait(self, parent):
>      """Clear wait data for task"""
>    c = context.cnx.cursor()
>     #unwait the task
>    q = """UPDATE task SET waiting='false' WHERE id = %(parent)s"""
>    context.commit_pending = True
>    c.execute(q,locals())
>    update = UpdateProcessor('task', clauses=['id=%(parent)s'], values=locals())
>    update.set(waiting=False)
>    update.execute()
>     #...and un-await its subtasks
>    q = """UPDATE task SET awaited='false' WHERE parent=%(parent)s"""
>    c.execute(q,locals())
>    update = UpdateProcessor('task', clauses=['parent=%(parent)s'], values=locals())
>    update.set(awaited=False)
>    update.execute()
>
> def taskSetWait(self,parent,tasks):
> def taskSetWait(self, parent, tasks):
>      """Mark task waiting and subtasks awaited"""
>    self.taskUnwait(parent)
>    c = context.cnx.cursor()
>    #mark tasks awaited
>    q = """UPDATE task SET waiting='true' WHERE id=%(parent)s"""
>    context.commit_pending = True
>    c.execute(q,locals())
>    # mark parent as waiting
>    update = UpdateProcessor('task', clauses=['id=%(parent)s'], values=locals())
>    update.set(waiting=True)
>    update.execute()
>    # mark children awaited
>     if tasks is None:
>        #wait on all subtasks
>        q = """UPDATE task SET awaited='true' WHERE parent=%(parent)s"""
>        c.execute(q,locals())
>        # wait on all subtasks
>        update = UpdateProcessor('task', clauses=['parent=%(parent)s'], values=locals())
>        update.set(awaited=True)
>        update.execute()
>     else:
>        for id in tasks:
>            q = """UPDATE task SET awaited='true' WHERE id=%(id)s"""
>            c.execute(q,locals())
>        # wait on specified subtasks
>        update = UpdateProcessor('task', clauses=['id IN %(tasks)s', 'parent=%(parent)s'], values=locals())
>        update.set(awaited=True)
>        update.execute()
>        # clear awaited flag on any other child tasks
>        update = UpdateProcessor('task', values=locals(),
>                        clauses=['id NOT IN %(tasks)s', 'parent=%(parent)s', 'awaited=true'])
>        update.set(awaited=False)
>        update.execute()
> def taskWaitCheck(self,parent):
>     """Return status of awaited subtask

[Mike McLean]

On 10/08/2015 11:24 PM, Peter Robinson wrote:
> On Thu, Oct 8, 2015 at 7:56 PM, Mike McLean  wrote:
> > This patch works around a deadlock issue that can occasionally happen
> > with chainmaven builds if the hub is using an older version of postgres.
>
> I think the patch is missing

gmail breaks the thread. see: [PATCH] Avoid multiple updates to same
rows in taskSetWait
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