In MongoDB serverStatus(), what is the meaning of “connection data handles currently active”?





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When running db.serverStatus() in the MongoDB shell (3.4, WiredTiger), the results contain the following data:



{
"connection data handles currently active" : 94862,
"connection sweep candidate became referenced" : 0,
"connection sweep dhandles closed" : 91885,
"connection sweep dhandles removed from hash list" : 648514,
"connection sweep time-of-death sets" : 1514067,
"connection sweeps" : 40077,
"session dhandles swept" : 110175,
"session sweep attempts" : 710643
}


What is the meaning of "connection data handles currently active"? Does it have an impact on the instance's performance?










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  • Good question... Checking wiredTiger source code from GitHub I could found only one hit /*! data-handle: connection data handles currently active */ #define WT_STAT_CONN_DH_CONN_HANDLE_COUNT 1131 no code lines what would explain how that value is count.

    – JJussi
    Sep 19 '17 at 11:09


















0















When running db.serverStatus() in the MongoDB shell (3.4, WiredTiger), the results contain the following data:



{
"connection data handles currently active" : 94862,
"connection sweep candidate became referenced" : 0,
"connection sweep dhandles closed" : 91885,
"connection sweep dhandles removed from hash list" : 648514,
"connection sweep time-of-death sets" : 1514067,
"connection sweeps" : 40077,
"session dhandles swept" : 110175,
"session sweep attempts" : 710643
}


What is the meaning of "connection data handles currently active"? Does it have an impact on the instance's performance?










share|improve this question














bumped to the homepage by Community 3 mins ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
















  • Good question... Checking wiredTiger source code from GitHub I could found only one hit /*! data-handle: connection data handles currently active */ #define WT_STAT_CONN_DH_CONN_HANDLE_COUNT 1131 no code lines what would explain how that value is count.

    – JJussi
    Sep 19 '17 at 11:09














0












0








0








When running db.serverStatus() in the MongoDB shell (3.4, WiredTiger), the results contain the following data:



{
"connection data handles currently active" : 94862,
"connection sweep candidate became referenced" : 0,
"connection sweep dhandles closed" : 91885,
"connection sweep dhandles removed from hash list" : 648514,
"connection sweep time-of-death sets" : 1514067,
"connection sweeps" : 40077,
"session dhandles swept" : 110175,
"session sweep attempts" : 710643
}


What is the meaning of "connection data handles currently active"? Does it have an impact on the instance's performance?










share|improve this question














When running db.serverStatus() in the MongoDB shell (3.4, WiredTiger), the results contain the following data:



{
"connection data handles currently active" : 94862,
"connection sweep candidate became referenced" : 0,
"connection sweep dhandles closed" : 91885,
"connection sweep dhandles removed from hash list" : 648514,
"connection sweep time-of-death sets" : 1514067,
"connection sweeps" : 40077,
"session dhandles swept" : 110175,
"session sweep attempts" : 710643
}


What is the meaning of "connection data handles currently active"? Does it have an impact on the instance's performance?







mongodb mongodb-3.4 wiredtiger






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asked Sep 19 '17 at 10:46









TzachTzach

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bumped to the homepage by Community 3 mins ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.







bumped to the homepage by Community 3 mins ago


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  • Good question... Checking wiredTiger source code from GitHub I could found only one hit /*! data-handle: connection data handles currently active */ #define WT_STAT_CONN_DH_CONN_HANDLE_COUNT 1131 no code lines what would explain how that value is count.

    – JJussi
    Sep 19 '17 at 11:09



















  • Good question... Checking wiredTiger source code from GitHub I could found only one hit /*! data-handle: connection data handles currently active */ #define WT_STAT_CONN_DH_CONN_HANDLE_COUNT 1131 no code lines what would explain how that value is count.

    – JJussi
    Sep 19 '17 at 11:09

















Good question... Checking wiredTiger source code from GitHub I could found only one hit /*! data-handle: connection data handles currently active */ #define WT_STAT_CONN_DH_CONN_HANDLE_COUNT 1131 no code lines what would explain how that value is count.

– JJussi
Sep 19 '17 at 11:09





Good question... Checking wiredTiger source code from GitHub I could found only one hit /*! data-handle: connection data handles currently active */ #define WT_STAT_CONN_DH_CONN_HANDLE_COUNT 1131 no code lines what would explain how that value is count.

– JJussi
Sep 19 '17 at 11:09










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Although I can't find any evidence for that in the documentation, it is probably the open file-handles that Mongo holds against the file storage.



I did a test that supports this idea:




  1. Creating new mongodb instance, "connection data handles currently active" minimum value is 11 (sometimes it becomes 12,13 and then back to 11).

  2. db.coll.insert({"foo":"bar"}) - "connection data handles currently active" min value = 13.


I did the same with other operations that cause mongo to create new files on disk, such as index creation, and I have noticed the same behavior.
We can conclude that this value, "connection data handles currently active" is related to the number of file-handles that mongo holds.



As for the question if it has an impact on the instance's performance, in some cases it could be true according to the next discussion at Jira:
https://jira.mongodb.org/browse/SERVER-27700






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    1 Answer
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    1 Answer
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    Although I can't find any evidence for that in the documentation, it is probably the open file-handles that Mongo holds against the file storage.



    I did a test that supports this idea:




    1. Creating new mongodb instance, "connection data handles currently active" minimum value is 11 (sometimes it becomes 12,13 and then back to 11).

    2. db.coll.insert({"foo":"bar"}) - "connection data handles currently active" min value = 13.


    I did the same with other operations that cause mongo to create new files on disk, such as index creation, and I have noticed the same behavior.
    We can conclude that this value, "connection data handles currently active" is related to the number of file-handles that mongo holds.



    As for the question if it has an impact on the instance's performance, in some cases it could be true according to the next discussion at Jira:
    https://jira.mongodb.org/browse/SERVER-27700






    share|improve this answer






























      0














      Although I can't find any evidence for that in the documentation, it is probably the open file-handles that Mongo holds against the file storage.



      I did a test that supports this idea:




      1. Creating new mongodb instance, "connection data handles currently active" minimum value is 11 (sometimes it becomes 12,13 and then back to 11).

      2. db.coll.insert({"foo":"bar"}) - "connection data handles currently active" min value = 13.


      I did the same with other operations that cause mongo to create new files on disk, such as index creation, and I have noticed the same behavior.
      We can conclude that this value, "connection data handles currently active" is related to the number of file-handles that mongo holds.



      As for the question if it has an impact on the instance's performance, in some cases it could be true according to the next discussion at Jira:
      https://jira.mongodb.org/browse/SERVER-27700






      share|improve this answer




























        0












        0








        0







        Although I can't find any evidence for that in the documentation, it is probably the open file-handles that Mongo holds against the file storage.



        I did a test that supports this idea:




        1. Creating new mongodb instance, "connection data handles currently active" minimum value is 11 (sometimes it becomes 12,13 and then back to 11).

        2. db.coll.insert({"foo":"bar"}) - "connection data handles currently active" min value = 13.


        I did the same with other operations that cause mongo to create new files on disk, such as index creation, and I have noticed the same behavior.
        We can conclude that this value, "connection data handles currently active" is related to the number of file-handles that mongo holds.



        As for the question if it has an impact on the instance's performance, in some cases it could be true according to the next discussion at Jira:
        https://jira.mongodb.org/browse/SERVER-27700






        share|improve this answer















        Although I can't find any evidence for that in the documentation, it is probably the open file-handles that Mongo holds against the file storage.



        I did a test that supports this idea:




        1. Creating new mongodb instance, "connection data handles currently active" minimum value is 11 (sometimes it becomes 12,13 and then back to 11).

        2. db.coll.insert({"foo":"bar"}) - "connection data handles currently active" min value = 13.


        I did the same with other operations that cause mongo to create new files on disk, such as index creation, and I have noticed the same behavior.
        We can conclude that this value, "connection data handles currently active" is related to the number of file-handles that mongo holds.



        As for the question if it has an impact on the instance's performance, in some cases it could be true according to the next discussion at Jira:
        https://jira.mongodb.org/browse/SERVER-27700







        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Sep 19 '17 at 17:11









        RDFozz

        9,89731531




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        answered Sep 19 '17 at 16:26









        Idan CohenIdan Cohen

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