Rebuilding indexes in a MongoDB collection helps optimize performance particularly after large write or update operations. In PyMongo, index rebuilding can be done using db.command() which is the recommended way to trigger index rebuilding in modern MongoDB versions. This process drops and recreates all indexes, ensuring they remain efficient and up-to-date for query execution.
Syntax
db.command('reIndex', <collection_name>)
Parameter:
- reIndex: command that tells to rebuild all indexes.
- <collection_name>: name of the collection (as a string) whose indexes should be rebuilt.
Sample of Collection
Example 1:
This code uses db.command() to rebuild all indexes on the Student collection.
from pymongo import MongoClient
client = MongoClient('localhost', 27017)
db = client['GFG']
collection_name = 'Student'
# Rebuild all indexes on the 'Student' collection
result = db.command('reIndex', 'Student')
print(result)
Output
Example 2:
In this Example, new students documents are inserted into the Student collection and then uses the db.command() method to rebuild all indexes on the collection.
from pymongo import MongoClient
client = MongoClient("mongodb://localhost:27017/")
db = client["GFG"]
collection = db["Student"]
# Insert some new records
students = [
{"_id": 10, "name": "Ankit", "Roll No": "1021", "Branch": "CSE"},
{"_id": 11, "name": "Neha", "Roll No": "1022", "Branch": "IT"}
]
collection.insert_many(students)
# Print only the newly inserted documents
print("Newly inserted documents:")
for doc in collection.find({"_id": {"$in": [10, 11]}}):
print(doc)
# Rebuild indexes
result = db.command("reIndex", "Student")
#Printing rebuilded indexes
print("Reindex result:")
print(result)
Output
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