[DOCS-12262] Do we / should we document $pull performance considerations? Created: 12/Dec/18 Updated: 30/Oct/23 |
|
| Status: | Closed |
| Project: | Documentation |
| Component/s: | manual, Server |
| Affects Version/s: | None |
| Fix Version/s: | Server_Docs_20231030 |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | James Wahlin | Assignee: | Unassigned |
| Resolution: | Won't Do | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
|
||||||||||||
| Participants: | |||||||||||||
| Days since reply: | 1 year, 14 weeks, 2 days ago | ||||||||||||
| Epic Link: | DOCSP-1769 | ||||||||||||
| Description |
DescriptionScope of changesImpact to Other DocsMVP (Work and Date)Resources (Scope or Design Docs, Invision, etc.) |
| Comments |
| Comment by Education Bot [ 31/Oct/22 ] |
|
Hello! This ticket has been closed due to inactivity. If you believe this ticket is still important, please reopen it and leave a comment to explain why. Thank you! |
| Comment by Brian Samek [ 13/Dec/18 ] |
That works for me. A note: I don't think it's just the array's size on disk that can trigger this. What matters is both the array's size and the number of update operations. |
| Comment by Asya Kamsky [ 13/Dec/18 ] |
|
This used to be something that we explicitly mentioned in some of the training ... Don't know if we still do...
|
| Comment by Ravind Kumar (Inactive) [ 13/Dec/18 ] |
|
So based on comments in HELP-8388 and
We'd need to do some testing to figure out which array operators would exhibit this behavior. I'm also concerned about how to define 'large' - it seems like we'd need to be specific that it's not the number of elements in the array, but the size on disk of those elements that cause an issue. Exactly where that marker is also might depend on the host hardware, e.g. one with more memory might better withstand the memory pressure of those kinds of operations. The simplest solution is a general purpose warning that performing update operations on large arrays (i.e. an array whose size on disk is > `n`) may result in large oplog entries for each document modified, which in turn can create memory pressure as those entries sit in memory. This effect may be pronounced on systems which are already close to capacity on memory usage. The bigger task would be to add some notes to the Production Notes section (possibly) about large size arrays and their consequences, possibly pulling from AskAsya -> Large Embedded Arrays brian@mongodb.com asya I'd appreciate your thoughts on the above.
|