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  1. C Driver
  2. CDRIVER-2389

Deprecate minPoolSize and log a warning if it's used

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    • Type: Icon: Improvement Improvement
    • Resolution: Fixed
    • Priority: Icon: Major - P3 Major - P3
    • 1.9.0
    • Affects Version/s: None
    • Component/s: libmongoc, network
    • Labels:
      None
    • Environment:
      Windows 10 x64

      Summary: minPoolSize does not do what anyone expects, and it's inconsistent with other drivers' options that have the same or similar names. What it actually does is not useful. Deprecate it, remove it from the main mongoc_uri_t documentation, and log a warning if it's used.

      —

      Original report: Setting minPoolSize in the URL to a non-zero value causes frequent connects/disconnects in a threaded environment. That is not the behavior that one would expect from this setting.

      Steps to reproduce:

      #include <iostream>
#include <thread>
#include <vector>
#include <bsoncxx/builder/stream/document.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/client.hpp>
#include <mongocxx/pool.hpp>

using namespace bsoncxx::builder::stream;
using namespace std;

int main() {
  mongocxx::instance inst;
  mongocxx::uri uri("mongodb://localhost/test?minPoolSize=1");
  mongocxx::pool pool(uri);
  pool.acquire()->database("test").collection("test").drop();
  vector<thread> thr;
  for (int j = 0; j < 3; ++j) {
    thr.emplace_back([&pool] {
      for (int i = 0; i < 2000; ++i) {
        auto conn = pool.acquire();
        auto db = conn->database("test");
        db.collection("test").insert_one(document{} << "idx" << i << finalize);
      }
    });
  }
  for (auto& t : thr) {
    if (t.joinable())
      t.join();
  }
}

      Results:

      minPoolSize=0

      2017-11-17T09:40:25.295+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54264 #1 (1 connection now open)
2017-11-17T09:40:25.296+0100 I NETWORK  [conn1] received client metadata from 127.0.0.1:54264 conn1: { driver: { name: "mongoc / mongocxx", version: "1.7.0-dev / 3.1.1-pre" }, os: { type: "Windows", name: "Windows", version: "6.2 (9200)", architecture: "x86_64" }, platform: "cfg=0x200c9 CC=MSVC 1900 CFLAGS=" /DWIN32 /D_WINDOWS /W3" LDFLAGS=" /machine:x64"" }
2017-11-17T09:40:25.297+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54265 #2 (2 connections now open)
2017-11-17T09:40:25.306+0100 I COMMAND  [conn2] CMD: drop test.test
2017-11-17T09:40:25.311+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54266 #3 (3 connections now open)
2017-11-17T09:40:25.311+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54267 #4 (4 connections now open)
2017-11-17T09:40:25.608+0100 I -        [conn3] end connection 127.0.0.1:54266 (4 connections now open)
2017-11-17T09:40:25.608+0100 I -        [conn2] end connection 127.0.0.1:54265 (4 connections now open)
2017-11-17T09:40:25.608+0100 I -        [conn4] end connection 127.0.0.1:54267 (4 connections now open)
2017-11-17T09:40:25.608+0100 I -        [conn1] end connection 127.0.0.1:54264 (2 connections now open)

      minPoolSize=1

      2017-11-17T09:43:34.750+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54237 #1 (1 connection now open)
2017-11-17T09:43:34.761+0100 I NETWORK  [conn1] received client metadata from 127.0.0.1:54237 conn1: { driver: { name: "mongoc / mongocxx", version: "1.7.0-dev / 3.1.1-pre" }, os: { type: "Windows", name: "Windows", version: "6.2 (9200)", architecture: "x86_64" }, platform: "cfg=0x200c9 CC=MSVC 1900 CFLAGS=" /DWIN32 /D_WINDOWS /W3" LDFLAGS=" /machine:x64"" }
2017-11-17T09:43:34.762+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54238 #2 (2 connections now open)
2017-11-17T09:43:34.763+0100 I COMMAND  [conn2] CMD: drop test.test
2017-11-17T09:43:34.769+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54239 #3 (3 connections now open)
2017-11-17T09:43:34.769+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54240 #4 (4 connections now open)
2017-11-17T09:43:34.820+0100 I -        [conn4] end connection 127.0.0.1:54240 (4 connections now open)
2017-11-17T09:43:34.820+0100 I -        [conn2] end connection 127.0.0.1:54238 (4 connections now open)
2017-11-17T09:43:34.822+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54241 #5 (3 connections now open)
2017-11-17T09:43:34.822+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54242 #6 (4 connections now open)
2017-11-17T09:43:34.873+0100 I -        [conn6] end connection 127.0.0.1:54242 (4 connections now open)
2017-11-17T09:43:34.874+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54243 #7 (4 connections now open)
2017-11-17T09:43:34.874+0100 I -        [conn5] end connection 127.0.0.1:54241 (3 connections now open)
2017-11-17T09:43:34.874+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54244 #8 (4 connections now open)
2017-11-17T09:43:34.880+0100 I -        [conn3] end connection 127.0.0.1:54239 (4 connections now open)
2017-11-17T09:43:34.880+0100 I -        [conn8] end connection 127.0.0.1:54244 (4 connections now open)
2017-11-17T09:43:34.881+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54245 #9 (3 connections now open)
2017-11-17T09:43:34.881+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54246 #10 (4 connections now open)
2017-11-17T09:43:34.892+0100 I -        [conn7] end connection 127.0.0.1:54243 (4 connections now open)
2017-11-17T09:43:34.892+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54247 #11 (4 connections now open)
2017-11-17T09:43:34.974+0100 I -        [conn9] end connection 127.0.0.1:54245 (4 connections now open)
2017-11-17T09:43:34.975+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54248 #12 (4 connections now open)
2017-11-17T09:43:35.061+0100 I -        [conn10] end connection 127.0.0.1:54246 (4 connections now open)
2017-11-17T09:43:35.062+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54249 #13 (4 connections now open)
2017-11-17T09:43:35.083+0100 I -        [conn12] end connection 127.0.0.1:54248 (4 connections now open)
2017-11-17T09:43:35.083+0100 I NETWORK  [thread1] connection accepted from 127.0.0.1:54250 #14 (4 connections now open)
2017-11-17T09:43:35.091+0100 I -        [conn13] end connection 127.0.0.1:54249 (4 connections now open)
2017-11-17T09:43:35.110+0100 I -        [conn11] end connection 127.0.0.1:54247 (3 connections now open)
2017-11-17T09:43:35.130+0100 I -        [conn14] end connection 127.0.0.1:54250 (2 connections now open)
2017-11-17T09:43:35.130+0100 I -        [conn1] end connection 127.0.0.1:54237 (1 connection now open)

            Assignee:
            jesse@mongodb.com A. Jesse Jiryu Davis
            Reporter:
            rustyx Rustam Abdullaev
            Votes:
            0 Vote for this issue
            Watchers:
            3 Start watching this issue

              Created:
              Updated:
              Resolved: