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Refactored expected indices after email w/ mongo

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Key order has no bearing on key order in queries other than for
Key order should be by greatest to least cardinality
Added sparse and unique declarations.
This commit is contained in:
Don Mitchell
2014-08-19 14:49:24 -04:00
parent a79703e8e6
commit ceae081cc7
1 changed files with 9 additions and 53 deletions
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62
mongo_indexes.md
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@@ -20,16 +20,14 @@ which can be `uploadDate`, `display_name`,
Replace existing index which leaves out `run` with this one:
```
ensureIndex({'_id.tag': 1, '_id.org': 1, '_id.course': 1, '_id.category': 1, '_id.run': 1})
ensureIndex({'content_son.tag': 1, 'content_son.org': 1, 'content_son.course': 1, 'content_son.category': 1, 'content_son.run': 1})
ensureIndex({'_id.org': 1, '_id.course': 1, '_id.name': 1}, {'sparse': true})
ensureIndex({'content_son.org': 1, 'content_son.course': 1, 'content_son.name': 1}, {'sparse': true})
ensureIndex({'_id.org': 1, '_id.course': 1, 'uploadDate': 1}, {'sparse': true})
ensureIndex({'_id.org': 1, '_id.course': 1, 'display_name': 1}, {'sparse': true})
ensureIndex({'content_son.org': 1, 'content_son.course': 1, 'uploadDate': 1}, {'sparse': true})
ensureIndex({'content_son.org': 1, 'content_son.course': 1, 'display_name': 1}, {'sparse': true})
```
Note: I'm not advocating adding one which leaves out `category` for now because that would only be
used for `delete_all_course_assets` which in the future should not actually delete the assets except
when doing garbage collection.
Remove index on `displayname`
modulestore:
============
@@ -41,7 +39,7 @@ and no field is omitted.
Because we often query for some subset of the id, we define this index:
```
ensureIndex({'_id.tag': 1, '_id.org': 1, '_id.course': 1, '_id.category': 1, '_id.name': 1, '_id.revision': 1})
ensureIndex({'_id.org': 1, '_id.course': 1, '_id.category': 1, '_id.name': 1})
```
Because we often scan for all category='course' regardless of the value of the other fields:
@@ -51,54 +49,12 @@ ensureIndex({'_id.category': 1})
Because lms calls get_parent_locations frequently (for path generation):
```
ensureIndex({'_id.tag': 1, '_id.org': 1, '_id.course': 1, 'definition.children': 1})
```
Remove these indices if they exist as I can find no use for them:
```
{ "_id.course": 1, "_id.org": 1, "_id.revision": 1, "definition.children": 1 }
{ "definition.children": 1 }
```
NOTE, that index will only aid queries which provide the keys in exactly that form and order. The query can
omit later fields of the query but not earlier. Thus ```modulestore.find({'_id.org': 'myu'})``` will not use
the index as it omits the tag. As soon as mongo comes across an index field omitted from the query, it stops
considering the index. On the other hand, ```modulestore.find({'_id.tag': 'i4x', '_id.org': 'myu', '_id.category': 'problem'})```
will use the index to get the records matching the tag and org and then will scan all of them
for matches to the category.
To find out if any records have the wrong id structure, run
```
db.fs.files.find({uploadDate: {$gt: startDate, $lt: endDate},
$where: function() {
var keys = ['category', 'name', 'course', 'tag', 'org', 'revision'];
for (var key in this._id) {
if (key != keys.shift()) {
return true;
}
}
return false;
}},
{_id: 1})
ensureIndex({'definition.children': 1}, {'sparse': true})
```
modulestore.active_versions
===========================
```
ensureIndex({'org': 1, 'offering': 1})
ensureIndex({'org': 1, 'course': 1, 'run': 1}, {'unique': true})
```
modulestore.structures
======================
```
ensureIndex({'previous_version': 1})
```
modulestore.definitions
=======================
```
ensureIndex({'category': 1})
```