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| author | Paul J. Davis <paul.joseph.davis@gmail.com> | 2018-06-18 12:34:02 -0500 |
|---|---|---|
| committer | Paul J. Davis <paul.joseph.davis@gmail.com> | 2018-06-19 09:28:14 -0500 |
| commit | f040d7531273ce77754ab29e08506951ee228fd6 (patch) | |
| tree | d69a58219f2180aab9cea396fa5a81032fff6049 | |
| parent | 3c9838528972ec55165fdd98bc70cec0bff4db3d (diff) | |
| download | couchdb-f040d7531273ce77754ab29e08506951ee228fd6.tar.gz | |
Add set_mqd_off_heap utility function
In Erlang VMs starting with version 19.0 have a new process_flag to
store messages off the process heap. This is extremely useful for
processes that can have huge numbers of messages in their mailbox. For
CouchDB this is most usually observed when couch_server backs up with a
large message queue which wedges the entire node.
This utility function will set a process's message_queue_data flag to
off_heap in a way that doesn't break builds of CouchDB on older Erlang
VMs while automatically enabling the flag on VMs that do support it.
| -rw-r--r-- | src/couch/src/couch_util.erl | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/couch/src/couch_util.erl b/src/couch/src/couch_util.erl index f3a9249f7..af1c0ef87 100644 --- a/src/couch/src/couch_util.erl +++ b/src/couch/src/couch_util.erl @@ -37,6 +37,7 @@ -export([unique_monotonic_integer/0]). -export([check_config_blacklist/1]). -export([check_md5/2]). +-export([set_mqd_off_heap/0]). -include_lib("couch/include/couch_db.hrl"). @@ -639,6 +640,15 @@ check_md5(Sig, Sig) -> ok; check_md5(_, _) -> throw(md5_mismatch). +set_mqd_off_heap() -> + try + erlang:process_flag(message_queue_data, off_heap), + ok + catch error:badarg -> + ok + end. + + ensure_loaded(Module) when is_atom(Module) -> case code:ensure_loaded(Module) of {module, Module} -> |