[DOCS-5003] mongoexport --forceTableScan description can be misleading Created: 13/Mar/15 Updated: 11/Jan/17 Resolved: 13/Jul/15 |
|
| Status: | Closed |
| Project: | Documentation |
| Component/s: | manual |
| Affects Version/s: | None |
| Fix Version/s: | 01112017-cleanup |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Andrew Ryder (Inactive) | Assignee: | Unassigned |
| Resolution: | Done | Votes: | 0 |
| Labels: | tools | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Participants: | |
| Days since reply: | 8 years, 31 weeks, 2 days ago |
| Description |
|
RE: http://docs.mongodb.org/manual/reference/program/mongoexport/#cmdoption--forceTableScan
The above statement gives the impression that when you use mongoexport normally (without --forceTableScan) it would reflect a single point in time. Which is not true. mongoexport never reflects a single point in time (unless you stop writes to the database prior to running it), regardless of the use or non-use of --forceTableScan. --forceTableScan might cause the output to include the same document twice (representing two variants in time) but it does not affect the chances of the output representing a sheared cross-section in time - resulting in a copy of the database which never actually existed. The only reason that $snapshot (i.e not using --forceTableScan) avoids duplicates in the output is because it walks the unique immutable _id index which cannot possibly result in seeing the same document twice - this is unrelated to a point-in-time though ($snapshot is a misleading name but we're stuck with it). |
| Comments |
| Comment by Githook User [ 13/Jul/15 ] |
|
Author: {u'username': u'kay-kim', u'name': u'kay', u'email': u'kay.kim@10gen.com'}Message: |
| Comment by Githook User [ 13/Jul/15 ] |
|
Author: {u'username': u'kay-kim', u'name': u'kay', u'email': u'kay.kim@10gen.com'}Message: |
| Comment by Githook User [ 13/Jul/15 ] |
|
Author: {u'username': u'kay-kim', u'name': u'kay', u'email': u'kay.kim@10gen.com'}Message: |