[couchdb] branch fix-compaction-race-condition created (now 46b124c)

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tonysun83 pushed a change to branch fix-compaction-race-condition
in repository https://gitbox.apache.org/repos/asf/couchdb.git.


      at 46b124c  fix race condition

This branch includes the following new commits:

     new 46b124c  fix race condition

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[couchdb] 01/01: fix race condition

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tonysun83 pushed a commit to branch fix-compaction-race-condition
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit 46b124c131ec812444adb2a235550a0d1aefd5eb
Author: Tony Sun <to...@gmail.com>
AuthorDate: Mon Sep 14 10:36:17 2020 -0700

    fix race condition
    
    This fixes a94e693f32672e4613bce0d80d0b9660f85275ea because a race
    condition exisited where the 'DOWN' message could be received
    before the compactor pid is spawned. Adding a synchronous call to
    get the compactor pid guarantees that the couch_db_updater process
    handling of finish_compaction has occurred.
---
 src/couch/src/couch_db.erl        | 9 +++++++++
 src/smoosh/src/smoosh_channel.erl | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/couch/src/couch_db.erl b/src/couch/src/couch_db.erl
index e1d726d..390a198 100644
--- a/src/couch/src/couch_db.erl
+++ b/src/couch/src/couch_db.erl
@@ -37,6 +37,7 @@
     get_committed_update_seq/1,
     get_compacted_seq/1,
     get_compactor_pid/1,
+    get_compactor_pid_sync/1,
     get_db_info/1,
     get_partition_info/2,
     get_del_doc_count/1,
@@ -572,6 +573,14 @@ get_compacted_seq(#db{}=Db) ->
 get_compactor_pid(#db{compactor_pid = Pid}) ->
     Pid.
 
+get_compactor_pid_sync(#db{main_pid=Pid}=Db) ->
+    case gen_server:call(Pid, compactor_pid, infinity) of
+        CPid when is_pid(CPid) ->
+            CPid;
+        _ ->
+            nil
+    end.
+
 get_db_info(Db) ->
     #db{
         name = Name,
diff --git a/src/smoosh/src/smoosh_channel.erl b/src/smoosh/src/smoosh_channel.erl
index 2a45c17..2bc98be 100644
--- a/src/smoosh/src/smoosh_channel.erl
+++ b/src/smoosh/src/smoosh_channel.erl
@@ -293,7 +293,7 @@ start_compact(State, Db) ->
 
 maybe_remonitor_cpid(State, DbName, Reason) when is_binary(DbName) ->
     {ok, Db} = couch_db:open_int(DbName, []),
-    case couch_db:get_compactor_pid(Db) of
+    case couch_db:get_compactor_pid_sync(Db) of
         nil ->
             couch_log:warning("exit for compaction of ~p: ~p",
                 [smoosh_utils:stringify(DbName), Reason]),