From: Sage Weil <sage@redhat.com>
Date: Fri, 7 Jun 2019 15:57:53 +0000 (-0500)
Subject: mon/OSDMonitor: make {removed,purged}_snap storage more efficient
X-Git-Tag: v15.1.0~2308^2~27
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=acd7e903d3eb7745e92dbcbf2b851a77d0dc1929;p=ceph.git

mon/OSDMonitor: make {removed,purged}_snap storage more efficient

Merge adjacent extents to keep the database smaller and lookups more
efficient.

Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/mon/OSDMonitor.cc b/src/mon/OSDMonitor.cc
index 982b92acfc52..ce60ac187ae4 100644
--- a/src/mon/OSDMonitor.cc
+++ b/src/mon/OSDMonitor.cc
@@ -6275,10 +6275,54 @@ void OSDMonitor::insert_snap_update(
   epoch_t epoch,
   MonitorDBStore::TransactionRef t)
 {
-  bufferlist v;
-  string k = _make_snap_key_value(purged, pool, start, end - start,
-				  pending_inc.epoch, &v);
-  t->put(OSD_SNAP_PREFIX, k, v);
+  snapid_t before_begin, before_end;
+  snapid_t after_begin, after_end;
+  int b = _lookup_snap(purged, pool, start - 1,
+		      &before_begin, &before_end);
+  int a = _lookup_snap(purged, pool, end,
+		       &after_begin, &after_end);
+  if (!b && !a) {
+    dout(10) << __func__ << (purged ? " (purged)" : " (removed)")
+	     << " [" << start << "," << end << ") - joins ["
+	     << before_begin << "," << before_end << ") and ["
+	     << after_begin << "," << after_end << ")" << dendl;
+    // erase only the begin record; we'll overwrite the end one.
+    t->erase(OSD_SNAP_PREFIX, _make_snap_key(purged, pool, before_end - 1));
+    bufferlist v;
+    string k = _make_snap_key_value(purged, pool,
+				    before_begin, after_end - before_begin,
+				    pending_inc.epoch, &v);
+    t->put(OSD_SNAP_PREFIX, k, v);
+  } else if (!b) {
+    dout(10) << __func__ << (purged ? " (purged)" : " (removed)")
+	     << " [" << start << "," << end << ") - join with earlier ["
+	     << before_begin << "," << before_end << ")" << dendl;
+    t->erase(OSD_SNAP_PREFIX, _make_snap_key(purged, pool, before_end - 1));
+    bufferlist v;
+    string k = _make_snap_key_value(purged, pool,
+				    before_begin, end - before_begin,
+				    pending_inc.epoch, &v);
+    t->put(OSD_SNAP_PREFIX, k, v);
+  } else if (!a) {
+    dout(10) << __func__ << (purged ? " (purged)" : " (removed)")
+	     << " [" << start << "," << end << ") - join with later ["
+	     << after_begin << "," << after_end << ")" << dendl;
+    // overwrite after record
+    bufferlist v;
+    string k = _make_snap_key_value(purged, pool,
+				    start, after_end - start,
+				    pending_inc.epoch, &v);
+    t->put(OSD_SNAP_PREFIX, k, v);
+  } else {
+    dout(10) << __func__ << (purged ? " (purged)" : " (removed)")
+	     << " [" << start << "," << end << ") - new"
+	     << dendl;
+    bufferlist v;
+    string k = _make_snap_key_value(purged, pool,
+				    start, end - start,
+				    pending_inc.epoch, &v);
+    t->put(OSD_SNAP_PREFIX, k, v);
+  }
 }
 
 bool OSDMonitor::try_prune_purged_snaps()