Do Blob properties on entities affect query performance?

Posted by Jaroslav Záruba on Stack Overflow See other posts from Stack Overflow or by Jaroslav Záruba
Published on 2010-05-09T06:12:42Z Indexed on 2010/05/09 6:18 UTC
Read the original article Hit count: 342

Filed under:

google-datastore

|

java

|

blob

|

google-app-engine

Hello

I'm trying to make my mind on whether to store a binary representation of an entity as its Blob property, or whether I better keep the blobs in some separate 'wrapping' class.
Possible impact on memory heap and/or a query execution time are my concerns in the first case, complexity votes against the other one.

I know Blobs are not indexed, i.e. index size is not what I'm worrying about. Also I assume for blobs Datastore puts defaultFetchGroup to false, but does it mean that blobs don't make a difference in queries?

Regards
J. Záruba

© Stack Overflow or respective owner

Related posts about google-datastore

Google Datastore w/ JDO: Access Times?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm hitting what appears (to me) strange behavior when I pull data from the google datastore over JDO. In particular, the query executes quickly (say 100 ms), but finding the size of the resulting List< takes about one second! Indeed, whatever operation I try to perform on the resulting list takes… >>> More
How to upload 6000 record to Google Datastore from csv file

as seen on Stack Overflow - Search for 'Stack Overflow'
http://code.google.com/appengine/docs/python/tools/uploadingdata.html is not clearly understand. Where i should call the bulkloader.py or appcfg.py? Should i import the csv file to local Google App Engine SDK first? How to keep the upload and download data process in existing application for datastore… >>> More
ArrayList throwing exception on retrieval from google datastore (with gwt, java)

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm using Google Web Toolkit with java and google datastore as database. The entity class has arraylist and on trying to retrieve the data from data base I'm getting the exception: Type 'org.datanucleus.sco.backed.ArrayList' was not included in the set of types which can be serialized by this SerializationPolicy… >>> More
google datastore - does it do lazy loading?

as seen on Stack Overflow - Search for 'Stack Overflow'
if I have a Customer object with a list of orders, declared using the db.ReferenceProperty after a while I may have huge amount of orders in there, if I pull the Customer object would I be in danger of pulling the complete set of orders? >>> More
From actionscript to google's datastore through java.

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm working on a flash game written in pure actionscript 3.0 in Flex. I've just finished implementing replays for the game, but want to store the top 10 hiscores' replay data on my google-app-engine'd website. I'm using Java for the app-engine stuff in Eclipse in java but I have no idea how to… >>> More

Related posts about java

Tomcat 6: Access Control Exception?

as seen on Server Fault - Search for 'Server Fault'
I'm trying to setup a tomcat6 server, and I'm trying to match another setup someone else established. However, my deployment (default Ubuntu install) uses a policy.d/ directory structure, and the established server just uses a catalina.policy file. I've tried setting every entry in policy.d to match… >>> More
Problem in creation MDB Queue connection at Jboss StartUp

as seen on Stack Overflow - Search for 'Stack Overflow'
I am not able to create a Queue connection in JBOSS4.2.3GA Version & Java1.5, as I am using MDB as per the below details. I am putting this MDB in a jar file(named utsJar.jar) and copied it in deploy folder of JBOSS, In the test env. this MDB works well but in another env. [ env settings and… >>> More
failing to establish connection between Postgres db and gwt

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am using Postgres and gwt 2.0 for one of my applications. I am facing problem connecting to the database. When I try to connect it gives "ClassNotFoundException". Here is what I get when I try to connect to database: java.lang.ClassNotFoundException: org.postgresql.Driver at java.net… >>> More
failing to establish connection between postgre db and gwt

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, For i am using postgre and gwt 2.0 for one of my applications. I am facing problem connecting to the database. When i try to connect it gives "ClassNotFoundException". Here is what i get when i try to connect to database: java.lang.ClassNotFoundException: org.postgresql.Driver at java.net… >>> More
Migration and deployement problems JBoss 4.2.2.GA to JBoss 6.0.0.M2

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I'm trying to migrate an application running on JBoss 4.2.2.GA to JBoss 6.0.0.M2 I give you some log to explain my problem : boot.log : 2010-03-16 09:59:29,406 ERROR [org.jboss.system.server.profileservice.ProfileServiceBootstrap] (Thread-2) Failed to load profile: Summary of incomplete deployments… >>> More