Revert "SERVER-47603 Rewrite db.currentOp() shell helper in terms of $currentOp aggregation stage"

This reverts commit 30fd64abd177d11362f3b3460897eff1f8b7ce53.

1 files changed, 15 insertions, 49 deletions

diff --git a/src/mongo/shell/db.js b/src/mongo/shell/db.js
index d6a59f8100c..bcdcea166a0 100644
--- a/src/mongo/shell/db.js
+++ b/src/mongo/shell/db.js
@@ -814,24 +814,7 @@ var commandUnsupported = function(res) {
 };
 
 DB.prototype.currentOp = function(arg) {
-    try {
-        const results = this.currentOpCursor(arg).toArray();
-        let res = {"inprog": results.length > 0 ? results : [], "ok": 1};
-        Object.defineProperty(res, "fsyncLock", {
-            get: function() {
-                throw Error(
-                    "fsyncLock is no longer included in the currentOp shell helper, run db.runCommand({currentOp: 1}) instead.");
-            }
-        });
-        return res;
-    } catch (e) {
-        return {"ok": 0, "code": e.code, "errmsg": "Error executing $currentOp: " + e.message};
-    }
-};
-DB.prototype.currentOP = DB.prototype.currentOp;
-
-DB.prototype.currentOpCursor = function(arg) {
-    let q = {};
+    var q = {};
     if (arg) {
         if (typeof (arg) == "object")
             Object.extend(q, arg);
@@ -839,40 +822,23 @@ DB.prototype.currentOpCursor = function(arg) {
             q["$all"] = true;
     }
 
-    // Convert the incoming currentOp command into an equivalent aggregate command
-    // of the form {aggregate:1, pipeline: [{$currentOp: {idleConnections: $all, allUsers:
-    // !$ownOps, truncateOps: false}}, {$match: {<user-defined filter>}}], cursor:{}}.
-    let pipeline = [];
-
-    let currOpArgs = {};
-    let currOpStage = {"$currentOp": currOpArgs};
-    currOpArgs["allUsers"] = !q["$ownOps"];
-    currOpArgs["idleConnections"] = !!q["$all"];
-    currOpArgs["truncateOps"] = false;
-
-    pipeline.push(currOpStage);
-
-    let matchArgs = {};
-    let matchStage = {"$match": matchArgs};
-    for (const fieldname of Object.keys(q)) {
-        if (fieldname !== "$all" && fieldname !== "$ownOps" && fieldname !== "$truncateOps") {
-            matchArgs[fieldname] = q[fieldname];
+    var commandObj = {"currentOp": 1};
+    Object.extend(commandObj, q);
+    var res = this.adminCommand(commandObj);
+    if (commandUnsupported(res)) {
+        // always send legacy currentOp with default (null) read preference (SERVER-17951)
+        const session = this.getSession();
+        const readPreference = session.getOptions().getReadPreference();
+        try {
+            session.getOptions().setReadPreference(null);
+            res = this.getSiblingDB("admin").$cmd.sys.inprog.findOne(q);
+        } finally {
+            session.getOptions().setReadPreference(readPreference);
         }
     }
-
-    pipeline.push(matchStage);
-
-    // The legacy db.currentOp() shell helper ignored read preference. To preserve this behavior we
-    // will temporarily set the session's read preference to null.
-    const session = this.getSession();
-    const readPreference = session.getOptions().getReadPreference();
-    try {
-        session.getOptions().setReadPreference("primaryPreferred");
-        return this.getSiblingDB("admin").aggregate(pipeline);
-    } finally {
-        session.getOptions().setReadPreference(readPreference);
-    }
+    return res;
 };
+DB.prototype.currentOP = DB.prototype.currentOp;
 
 DB.prototype.killOp = function(op) {
     if (!op)