MongoDB : Why should we close the cursor after it is used? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern) Data science time! April 2019 and salary with experience The Ask Question Wizard is Live!Does MongoCursor always need explictly closing?Cursor leak in MongoDBCreate a list from DbCursor in MongoDB and JavaMongoDB or CouchDB - fit for production?MongoDB vs. CassandraNoSQL (MongoDB) vs Lucene (or Solr) as your databaseHow to query MongoDB with “like”?What did MongoDB not being ACID compliant before v4 really mean?How do I drop a MongoDB database from the command line?Why shouldn't I use mysql_* functions in PHP?“Large data” work flows using pandasWhat is a Cursor in MongoDB?Close a MongoDB Tailable Cursor in JAVA
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MongoDB : Why should we close the cursor after it is used?
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)
Data science time! April 2019 and salary with experience
The Ask Question Wizard is Live!Does MongoCursor always need explictly closing?Cursor leak in MongoDBCreate a list from DbCursor in MongoDB and JavaMongoDB or CouchDB - fit for production?MongoDB vs. CassandraNoSQL (MongoDB) vs Lucene (or Solr) as your databaseHow to query MongoDB with “like”?What did MongoDB not being ACID compliant before v4 really mean?How do I drop a MongoDB database from the command line?Why shouldn't I use mysql_* functions in PHP?“Large data” work flows using pandasWhat is a Cursor in MongoDB?Close a MongoDB Tailable Cursor in JAVA
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I have seen that people close the cursor after it has been used. I also read in documentation that server closes the cursor after 10 minutes of inactivity.
I searched the net but didn't find proper answer. I am new to both database and MongoDB.
Why is it necessary to close the cursor?
mongodb memory-leaks cursor mongodb-query database
edited Sep 22 '17 at 17:57
Community♦
11
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
add a comment |
I have seen that people close the cursor after it has been used. I also read in documentation that server closes the cursor after 10 minutes of inactivity.
I searched the net but didn't find proper answer. I am new to both database and MongoDB.
Why is it necessary to close the cursor?
mongodb memory-leaks cursor mongodb-query database
edited Sep 22 '17 at 17:57
Community♦
11
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
add a comment |
I have seen that people close the cursor after it has been used. I also read in documentation that server closes the cursor after 10 minutes of inactivity.
I searched the net but didn't find proper answer. I am new to both database and MongoDB.
Why is it necessary to close the cursor?
mongodb memory-leaks cursor mongodb-query database
edited Sep 22 '17 at 17:57
Community♦
11
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
I have seen that people close the cursor after it has been used. I also read in documentation that server closes the cursor after 10 minutes of inactivity.
I searched the net but didn't find proper answer. I am new to both database and MongoDB.
Why is it necessary to close the cursor?
mongodb memory-leaks cursor mongodb-query database
mongodb memory-leaks cursor mongodb-query database
edited Sep 22 '17 at 17:57
Community♦
11
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
edited Sep 22 '17 at 17:57
Community♦
11
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
edited Sep 22 '17 at 17:57
Community♦
11
edited Sep 22 '17 at 17:57
Community♦
11
edited Sep 22 '17 at 17:57
Community♦
11
11
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
asked Jun 17 '14 at 9:50
Pratik PatelPratik Patel
7311133
7311133
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
Closing the cursor is only really required when you do not "exhaust" the results. Or in other terms, iterate over all the possible results returned by the cursor.
Leaving a "cursor" open is like leaving an open connection that never gets re-used. These things are not free. In fact the standard connection cost is 1MB (approx). So if you are leaving a lot of "partially iterated" cursors hanging around there is a general overhead in terms of an active connection and it's memory usage.
If in fact you actually always iterate "all" of the results (and that includes a "limit" which is a "cursor modifier") then the cursor will close and all is okay.
General usage will be that you actually exhaust/deplete the cursor by going through all of the results. Therefore there is no explicit need to destroy.
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
It depends on your usage, but at least in my web application - the client handles the closing.
Why? because my web application follows the pattern of short & stateless request handling (you get a request from the browser, build an HTTP response quickly - less than a second - and this response relies on mongo data). So my client only needs the connection for 1 second.
Now, consider what if I have (say) 50 requests per minute... my server handles them comfortably. But it would have crashed if each request were to hold on to resources for 10 minutes... E.g. after 9 minutes I would have 450 unnecessary open resources...
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
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2 Answers
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2 Answers
2
active
oldest
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oldest
votes
Closing the cursor is only really required when you do not "exhaust" the results. Or in other terms, iterate over all the possible results returned by the cursor.
Leaving a "cursor" open is like leaving an open connection that never gets re-used. These things are not free. In fact the standard connection cost is 1MB (approx). So if you are leaving a lot of "partially iterated" cursors hanging around there is a general overhead in terms of an active connection and it's memory usage.
If in fact you actually always iterate "all" of the results (and that includes a "limit" which is a "cursor modifier") then the cursor will close and all is okay.
General usage will be that you actually exhaust/deplete the cursor by going through all of the results. Therefore there is no explicit need to destroy.
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
Closing the cursor is only really required when you do not "exhaust" the results. Or in other terms, iterate over all the possible results returned by the cursor.
Leaving a "cursor" open is like leaving an open connection that never gets re-used. These things are not free. In fact the standard connection cost is 1MB (approx). So if you are leaving a lot of "partially iterated" cursors hanging around there is a general overhead in terms of an active connection and it's memory usage.
If in fact you actually always iterate "all" of the results (and that includes a "limit" which is a "cursor modifier") then the cursor will close and all is okay.
General usage will be that you actually exhaust/deplete the cursor by going through all of the results. Therefore there is no explicit need to destroy.
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
Closing the cursor is only really required when you do not "exhaust" the results. Or in other terms, iterate over all the possible results returned by the cursor.
Leaving a "cursor" open is like leaving an open connection that never gets re-used. These things are not free. In fact the standard connection cost is 1MB (approx). So if you are leaving a lot of "partially iterated" cursors hanging around there is a general overhead in terms of an active connection and it's memory usage.
If in fact you actually always iterate "all" of the results (and that includes a "limit" which is a "cursor modifier") then the cursor will close and all is okay.
General usage will be that you actually exhaust/deplete the cursor by going through all of the results. Therefore there is no explicit need to destroy.
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
Closing the cursor is only really required when you do not "exhaust" the results. Or in other terms, iterate over all the possible results returned by the cursor.
Leaving a "cursor" open is like leaving an open connection that never gets re-used. These things are not free. In fact the standard connection cost is 1MB (approx). So if you are leaving a lot of "partially iterated" cursors hanging around there is a general overhead in terms of an active connection and it's memory usage.
If in fact you actually always iterate "all" of the results (and that includes a "limit" which is a "cursor modifier") then the cursor will close and all is okay.
General usage will be that you actually exhaust/deplete the cursor by going through all of the results. Therefore there is no explicit need to destroy.
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
answered Jun 17 '14 at 10:21
Neil LunnNeil Lunn
102k23181189
102k23181189
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
It depends on your usage, but at least in my web application - the client handles the closing.
Why? because my web application follows the pattern of short & stateless request handling (you get a request from the browser, build an HTTP response quickly - less than a second - and this response relies on mongo data). So my client only needs the connection for 1 second.
Now, consider what if I have (say) 50 requests per minute... my server handles them comfortably. But it would have crashed if each request were to hold on to resources for 10 minutes... E.g. after 9 minutes I would have 450 unnecessary open resources...
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
It depends on your usage, but at least in my web application - the client handles the closing.
Why? because my web application follows the pattern of short & stateless request handling (you get a request from the browser, build an HTTP response quickly - less than a second - and this response relies on mongo data). So my client only needs the connection for 1 second.
Now, consider what if I have (say) 50 requests per minute... my server handles them comfortably. But it would have crashed if each request were to hold on to resources for 10 minutes... E.g. after 9 minutes I would have 450 unnecessary open resources...
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
It depends on your usage, but at least in my web application - the client handles the closing.
Why? because my web application follows the pattern of short & stateless request handling (you get a request from the browser, build an HTTP response quickly - less than a second - and this response relies on mongo data). So my client only needs the connection for 1 second.
Now, consider what if I have (say) 50 requests per minute... my server handles them comfortably. But it would have crashed if each request were to hold on to resources for 10 minutes... E.g. after 9 minutes I would have 450 unnecessary open resources...
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
It depends on your usage, but at least in my web application - the client handles the closing.
Why? because my web application follows the pattern of short & stateless request handling (you get a request from the browser, build an HTTP response quickly - less than a second - and this response relies on mongo data). So my client only needs the connection for 1 second.
Now, consider what if I have (say) 50 requests per minute... my server handles them comfortably. But it would have crashed if each request were to hold on to resources for 10 minutes... E.g. after 9 minutes I would have 450 unnecessary open resources...
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
answered Jun 17 '14 at 10:19
Pelit MamaniPelit Mamani
1,6012911
1,6012911
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
Thank you for the answer.
– Pratik Patel
Jun 17 '14 at 10:49
add a comment |
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