Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
Thanks Tyler! On Thu, Feb 3, 2011 at 12:06 PM, Tyler Hobbs ty...@datastax.com wrote: On Wed, Feb 2, 2011 at 3:27 PM, Aditya Narayan ady...@gmail.com wrote: Can I have some more feedback about my schema perhaps somewhat more criticisive/harsh ? It sounds reasonable to me. Since you're writing/reading all of the subcolumns at the same time, I would opt for a standard column with the tags serialized into a column value. I don't think you need to worry about row lengths here. Depending on the reminder size and how many times it's likely to be repeated in the timeline, you could explore denormalizing a bit more by storing the reminders in the timelines themselves, perhaps with a separate row per (user, tag) combination. This would cut down on your seeks quite a bit, but it may not be necessary at this point (or at all). -- Tyler Hobbs Software Engineer, DataStax Maintainer of the pycassa Cassandra Python client library
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline of reminders set by user to be presented to the user, the timeline row of each user would contain the Id/Key(s) (of the Reminder rows) as the supercolumn names and the subcolumns inside that supercolumns could contain the list of tags associated with particular reminder. All tags set at once during first write. The no of tags(subcolumns) will be around 8 maximum. Any comments, suggestions and feedback on the schema design are requested.. Thanks Aditya Narayan On Wed, Feb 2, 2011 at 7:49 PM, Aditya Narayan ady...@gmail.com wrote: Hey all, I need to store supercolumns each with around 8 subcolumns; All the data for a supercolumn is written at once and all subcolumns need to be retrieved together. The data in each subcolumn is not big, it just contains keys to other rows. Would it be preferred to have a supercolumn family or just a standard column family containing all the subcolumns data serialized in single column(s) ? Thanks Aditya Narayan
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
To reiterate, so I know we're both on the same page, your schema would be something like this: - A column family (as you describe) to store the details of a reminder. One reminder per row. The row key would be a TimeUUID. - A super column family to store the reminders for each user, for each day. The row key would be something like: MMDD:user_id. The column names would simply be the TimeUUID of the messages. The sub column names would be the tag names of the various reminders. The idea is that you would then get a slice of each row for a user, for a day, that would only contain sub column names with the tags you're looking for? Then based upon the column names returned, you'd look-up the reminders. That seems like a solid schema to me. Bill- On 02/02/2011 09:37 AM, Aditya Narayan wrote: Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline of reminders set by user to be presented to the user, the timeline row of each user would contain the Id/Key(s) (of the Reminder rows) as the supercolumn names and the subcolumns inside that supercolumns could contain the list of tags associated with particular reminder. All tags set at once during first write. The no of tags(subcolumns) will be around 8 maximum. Any comments, suggestions and feedback on the schema design are requested.. Thanks Aditya Narayan On Wed, Feb 2, 2011 at 7:49 PM, Aditya Narayanady...@gmail.com wrote: Hey all, I need to store supercolumns each with around 8 subcolumns; All the data for a supercolumn is written at once and all subcolumns need to be retrieved together. The data in each subcolumn is not big, it just contains keys to other rows. Would it be preferred to have a supercolumn family or just a standard column family containing all the subcolumns data serialized in single column(s) ? Thanks Aditya Narayan
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
I think you got it exactly what I wanted to convey except for few things I want to clarify: I was thinking of a single row containing all reminders ( not split by day). History of the reminders need to be maintained for some time. After certain time (say 3 or 6 months) they may be deleted by ttl facility. While presenting the reminders timeline to the user, latest supercolumns like around 50 from the start_end will be picked up and their subcolumns values will be compared to the Tags user has chosen to see and, corresponding to the filtered subcolumn values(tags), the rows of the reminder details would be picked up.. Is supercolumn a preferable choice for this ? Can there be a better schema than this ? -Aditya Narayan On Wed, Feb 2, 2011 at 8:54 PM, William R Speirs bill.spe...@gmail.com wrote: To reiterate, so I know we're both on the same page, your schema would be something like this: - A column family (as you describe) to store the details of a reminder. One reminder per row. The row key would be a TimeUUID. - A super column family to store the reminders for each user, for each day. The row key would be something like: MMDD:user_id. The column names would simply be the TimeUUID of the messages. The sub column names would be the tag names of the various reminders. The idea is that you would then get a slice of each row for a user, for a day, that would only contain sub column names with the tags you're looking for? Then based upon the column names returned, you'd look-up the reminders. That seems like a solid schema to me. Bill- On 02/02/2011 09:37 AM, Aditya Narayan wrote: Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline of reminders set by user to be presented to the user, the timeline row of each user would contain the Id/Key(s) (of the Reminder rows) as the supercolumn names and the subcolumns inside that supercolumns could contain the list of tags associated with particular reminder. All tags set at once during first write. The no of tags(subcolumns) will be around 8 maximum. Any comments, suggestions and feedback on the schema design are requested.. Thanks Aditya Narayan On Wed, Feb 2, 2011 at 7:49 PM, Aditya Narayanady...@gmail.com wrote: Hey all, I need to store supercolumns each with around 8 subcolumns; All the data for a supercolumn is written at once and all subcolumns need to be retrieved together. The data in each subcolumn is not big, it just contains keys to other rows. Would it be preferred to have a supercolumn family or just a standard column family containing all the subcolumns data serialized in single column(s) ? Thanks Aditya Narayan
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
Any time I see/hear a single row containing all ... I get nervous. That single row is going to reside on a single node. That is potentially a lot of load (don't know the system) for that single node. Why wouldn't you split it by at least user? If it won't be a lot of load, then why are you using Cassandra? This seems like something that could easily fit into an SQL/relational style DB. If it's too much data (millions of users, 100s of millions of reminders) for a standard SQL/relational model, then it's probably too much for a single row. I'm not familiar with the TTL functionality of Cassandra... sorry cannot help/comment there, still learning :-) Yea, my $0.02 is that this is an effective way to leverage super columns. Bill- On 02/02/2011 10:43 AM, Aditya Narayan wrote: I think you got it exactly what I wanted to convey except for few things I want to clarify: I was thinking of a single row containing all reminders ( not split by day). History of the reminders need to be maintained for some time. After certain time (say 3 or 6 months) they may be deleted by ttl facility. While presenting the reminders timeline to the user, latest supercolumns like around 50 from the start_end will be picked up and their subcolumns values will be compared to the Tags user has chosen to see and, corresponding to the filtered subcolumn values(tags), the rows of the reminder details would be picked up.. Is supercolumn a preferable choice for this ? Can there be a better schema than this ? -Aditya Narayan On Wed, Feb 2, 2011 at 8:54 PM, William R Speirsbill.spe...@gmail.com wrote: To reiterate, so I know we're both on the same page, your schema would be something like this: - A column family (as you describe) to store the details of a reminder. One reminder per row. The row key would be a TimeUUID. - A super column family to store the reminders for each user, for each day. The row key would be something like: MMDD:user_id. The column names would simply be the TimeUUID of the messages. The sub column names would be the tag names of the various reminders. The idea is that you would then get a slice of each row for a user, for a day, that would only contain sub column names with the tags you're looking for? Then based upon the column names returned, you'd look-up the reminders. That seems like a solid schema to me. Bill- On 02/02/2011 09:37 AM, Aditya Narayan wrote: Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline of reminders set by user to be presented to the user, the timeline row of each user would contain the Id/Key(s) (of the Reminder rows) as the supercolumn names and the subcolumns inside that supercolumns could contain the list of tags associated with particular reminder. All tags set at once during first write. The no of tags(subcolumns) will be around 8 maximum. Any comments, suggestions and feedback on the schema design are requested.. Thanks Aditya Narayan On Wed, Feb 2, 2011 at 7:49 PM, Aditya Narayanady...@gmail.comwrote: Hey all, I need to store supercolumns each with around 8 subcolumns; All the data for a supercolumn is written at once and all subcolumns need to be retrieved together. The data in each subcolumn is not big, it just contains keys to other rows. Would it be preferred to have a supercolumn family or just a standard column family containing all the subcolumns data serialized in single column(s) ? Thanks Aditya Narayan
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
You got me wrong perhaps.. I am already splitting the row on per user basis ofcourse, otherwise the schema wont make sense for my usage. The row contains only *reminders of a single user* sorted in chronological order. The reminder Id are stored as supercolumn name and subcolumn contain tags for that reminder. On Wed, Feb 2, 2011 at 9:19 PM, William R Speirs bill.spe...@gmail.com wrote: Any time I see/hear a single row containing all ... I get nervous. That single row is going to reside on a single node. That is potentially a lot of load (don't know the system) for that single node. Why wouldn't you split it by at least user? If it won't be a lot of load, then why are you using Cassandra? This seems like something that could easily fit into an SQL/relational style DB. If it's too much data (millions of users, 100s of millions of reminders) for a standard SQL/relational model, then it's probably too much for a single row. I'm not familiar with the TTL functionality of Cassandra... sorry cannot help/comment there, still learning :-) Yea, my $0.02 is that this is an effective way to leverage super columns. Bill- On 02/02/2011 10:43 AM, Aditya Narayan wrote: I think you got it exactly what I wanted to convey except for few things I want to clarify: I was thinking of a single row containing all reminders ( not split by day). History of the reminders need to be maintained for some time. After certain time (say 3 or 6 months) they may be deleted by ttl facility. While presenting the reminders timeline to the user, latest supercolumns like around 50 from the start_end will be picked up and their subcolumns values will be compared to the Tags user has chosen to see and, corresponding to the filtered subcolumn values(tags), the rows of the reminder details would be picked up.. Is supercolumn a preferable choice for this ? Can there be a better schema than this ? -Aditya Narayan On Wed, Feb 2, 2011 at 8:54 PM, William R Speirsbill.spe...@gmail.com wrote: To reiterate, so I know we're both on the same page, your schema would be something like this: - A column family (as you describe) to store the details of a reminder. One reminder per row. The row key would be a TimeUUID. - A super column family to store the reminders for each user, for each day. The row key would be something like: MMDD:user_id. The column names would simply be the TimeUUID of the messages. The sub column names would be the tag names of the various reminders. The idea is that you would then get a slice of each row for a user, for a day, that would only contain sub column names with the tags you're looking for? Then based upon the column names returned, you'd look-up the reminders. That seems like a solid schema to me. Bill- On 02/02/2011 09:37 AM, Aditya Narayan wrote: Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline of reminders set by user to be presented to the user, the timeline row of each user would contain the Id/Key(s) (of the Reminder rows) as the supercolumn names and the subcolumns inside that supercolumns could contain the list of tags associated with particular reminder. All tags set at once during first write. The no of tags(subcolumns) will be around 8 maximum. Any comments, suggestions and feedback on the schema design are requested.. Thanks Aditya Narayan On Wed, Feb 2, 2011 at 7:49 PM, Aditya Narayanady...@gmail.com wrote: Hey all, I need to store supercolumns each with around 8 subcolumns; All the data for a supercolumn is written at once and all subcolumns need to be retrieved together. The data in each subcolumn is not big, it just contains keys to other rows. Would it be preferred to have a supercolumn family or just a standard column family containing all the subcolumns data serialized in single column(s) ? Thanks Aditya Narayan
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
I did not understand before... sorry. Again, depending upon how many reminders you have for a single user, this could be a long/wide row. Again, it really comes down to how many reminders are we talking about and how often will they be read/written. While a single row can contain millions (maybe more) columns, that doesn't mean it's a good idea. I'm working on a logging system with Cassandra and ran into this same type of problem. Do I put all of the messages for a single system into a single row keyed off that system's name? I quickly came to the answer of no and now I break my row keys into POSIX_timestamp:system where my timestamps are buckets for every 5 minutes. This nicely distributes the load across the nodes in my system. Bill- On 02/02/2011 11:18 AM, Aditya Narayan wrote: You got me wrong perhaps.. I am already splitting the row on per user basis ofcourse, otherwise the schema wont make sense for my usage. The row contains only *reminders of a single user* sorted in chronological order. The reminder Id are stored as supercolumn name and subcolumn contain tags for that reminder. On Wed, Feb 2, 2011 at 9:19 PM, William R Speirsbill.spe...@gmail.com wrote: Any time I see/hear a single row containing all ... I get nervous. That single row is going to reside on a single node. That is potentially a lot of load (don't know the system) for that single node. Why wouldn't you split it by at least user? If it won't be a lot of load, then why are you using Cassandra? This seems like something that could easily fit into an SQL/relational style DB. If it's too much data (millions of users, 100s of millions of reminders) for a standard SQL/relational model, then it's probably too much for a single row. I'm not familiar with the TTL functionality of Cassandra... sorry cannot help/comment there, still learning :-) Yea, my $0.02 is that this is an effective way to leverage super columns. Bill- On 02/02/2011 10:43 AM, Aditya Narayan wrote: I think you got it exactly what I wanted to convey except for few things I want to clarify: I was thinking of a single row containing all reminders (not split by day). History of the reminders need to be maintained for some time. After certain time (say 3 or 6 months) they may be deleted by ttl facility. While presenting the reminders timeline to the user, latest supercolumns like around 50 from the start_end will be picked up and their subcolumns values will be compared to the Tags user has chosen to see and, corresponding to the filtered subcolumn values(tags), the rows of the reminder details would be picked up.. Is supercolumn a preferable choice for this ? Can there be a better schema than this ? -Aditya Narayan On Wed, Feb 2, 2011 at 8:54 PM, William R Speirsbill.spe...@gmail.com wrote: To reiterate, so I know we're both on the same page, your schema would be something like this: - A column family (as you describe) to store the details of a reminder. One reminder per row. The row key would be a TimeUUID. - A super column family to store the reminders for each user, for each day. The row key would be something like: MMDD:user_id. The column names would simply be the TimeUUID of the messages. The sub column names would be the tag names of the various reminders. The idea is that you would then get a slice of each row for a user, for a day, that would only contain sub column names with the tags you're looking for? Then based upon the column names returned, you'd look-up the reminders. That seems like a solid schema to me. Bill- On 02/02/2011 09:37 AM, Aditya Narayan wrote: Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline of reminders set by user to be presented to the user, the timeline row of each user would contain the Id/Key(s) (of the Reminder rows) as the supercolumn names and the subcolumns inside that supercolumns could contain the list of tags associated with particular reminder. All tags set at once during first write. The no of tags(subcolumns) will be around 8 maximum. Any comments, suggestions and feedback on the schema design are requested.. Thanks Aditya Narayan On Wed, Feb 2, 2011 at 7:49 PM, Aditya Narayanady...@gmail.com wrote: Hey all, I need to store supercolumns each with around 8 subcolumns; All the data for a supercolumn is written at once and all subcolumns need to be retrieved
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
@Bill Thank you BIll! @Cassandra users Can others also leave their suggestions and comments about my schema, please. Also my question about whether to use a superColumn or alternatively, just store the data (that would otherwise be stored in subcolumns) as serialized into a single column in standard type column family. Thanks -Aditya Narayan On Wed, Feb 2, 2011 at 10:11 PM, William R Speirs bill.spe...@gmail.com wrote: I did not understand before... sorry. Again, depending upon how many reminders you have for a single user, this could be a long/wide row. Again, it really comes down to how many reminders are we talking about and how often will they be read/written. While a single row can contain millions (maybe more) columns, that doesn't mean it's a good idea. I'm working on a logging system with Cassandra and ran into this same type of problem. Do I put all of the messages for a single system into a single row keyed off that system's name? I quickly came to the answer of no and now I break my row keys into POSIX_timestamp:system where my timestamps are buckets for every 5 minutes. This nicely distributes the load across the nodes in my system. Bill- On 02/02/2011 11:18 AM, Aditya Narayan wrote: You got me wrong perhaps.. I am already splitting the row on per user basis ofcourse, otherwise the schema wont make sense for my usage. The row contains only *reminders of a single user* sorted in chronological order. The reminder Id are stored as supercolumn name and subcolumn contain tags for that reminder. On Wed, Feb 2, 2011 at 9:19 PM, William R Speirsbill.spe...@gmail.com wrote: Any time I see/hear a single row containing all ... I get nervous. That single row is going to reside on a single node. That is potentially a lot of load (don't know the system) for that single node. Why wouldn't you split it by at least user? If it won't be a lot of load, then why are you using Cassandra? This seems like something that could easily fit into an SQL/relational style DB. If it's too much data (millions of users, 100s of millions of reminders) for a standard SQL/relational model, then it's probably too much for a single row. I'm not familiar with the TTL functionality of Cassandra... sorry cannot help/comment there, still learning :-) Yea, my $0.02 is that this is an effective way to leverage super columns. Bill- On 02/02/2011 10:43 AM, Aditya Narayan wrote: I think you got it exactly what I wanted to convey except for few things I want to clarify: I was thinking of a single row containing all reminders ( not split by day). History of the reminders need to be maintained for some time. After certain time (say 3 or 6 months) they may be deleted by ttl facility. While presenting the reminders timeline to the user, latest supercolumns like around 50 from the start_end will be picked up and their subcolumns values will be compared to the Tags user has chosen to see and, corresponding to the filtered subcolumn values(tags), the rows of the reminder details would be picked up.. Is supercolumn a preferable choice for this ? Can there be a better schema than this ? -Aditya Narayan On Wed, Feb 2, 2011 at 8:54 PM, William R Speirsbill.spe...@gmail.com wrote: To reiterate, so I know we're both on the same page, your schema would be something like this: - A column family (as you describe) to store the details of a reminder. One reminder per row. The row key would be a TimeUUID. - A super column family to store the reminders for each user, for each day. The row key would be something like: MMDD:user_id. The column names would simply be the TimeUUID of the messages. The sub column names would be the tag names of the various reminders. The idea is that you would then get a slice of each row for a user, for a day, that would only contain sub column names with the tags you're looking for? Then based upon the column names returned, you'd look-up the reminders. That seems like a solid schema to me. Bill- On 02/02/2011 09:37 AM, Aditya Narayan wrote: Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline of reminders set by user to be presented to the user, the timeline row of each user would contain the Id/Key(s) (of the Reminder rows) as the supercolumn names and the subcolumns inside that
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
Can I have some more feedback about my schema perhaps somewhat more criticisive/harsh ? Thanks again, Aditya Narayan On Wed, Feb 2, 2011 at 10:27 PM, Aditya Narayan ady...@gmail.com wrote: @Bill Thank you BIll! @Cassandra users Can others also leave their suggestions and comments about my schema, please. Also my question about whether to use a superColumn or alternatively, just store the data (that would otherwise be stored in subcolumns) as serialized into a single column in standard type column family. Thanks -Aditya Narayan On Wed, Feb 2, 2011 at 10:11 PM, William R Speirs bill.spe...@gmail.com wrote: I did not understand before... sorry. Again, depending upon how many reminders you have for a single user, this could be a long/wide row. Again, it really comes down to how many reminders are we talking about and how often will they be read/written. While a single row can contain millions (maybe more) columns, that doesn't mean it's a good idea. I'm working on a logging system with Cassandra and ran into this same type of problem. Do I put all of the messages for a single system into a single row keyed off that system's name? I quickly came to the answer of no and now I break my row keys into POSIX_timestamp:system where my timestamps are buckets for every 5 minutes. This nicely distributes the load across the nodes in my system. Bill- On 02/02/2011 11:18 AM, Aditya Narayan wrote: You got me wrong perhaps.. I am already splitting the row on per user basis ofcourse, otherwise the schema wont make sense for my usage. The row contains only *reminders of a single user* sorted in chronological order. The reminder Id are stored as supercolumn name and subcolumn contain tags for that reminder. On Wed, Feb 2, 2011 at 9:19 PM, William R Speirsbill.spe...@gmail.com wrote: Any time I see/hear a single row containing all ... I get nervous. That single row is going to reside on a single node. That is potentially a lot of load (don't know the system) for that single node. Why wouldn't you split it by at least user? If it won't be a lot of load, then why are you using Cassandra? This seems like something that could easily fit into an SQL/relational style DB. If it's too much data (millions of users, 100s of millions of reminders) for a standard SQL/relational model, then it's probably too much for a single row. I'm not familiar with the TTL functionality of Cassandra... sorry cannot help/comment there, still learning :-) Yea, my $0.02 is that this is an effective way to leverage super columns. Bill- On 02/02/2011 10:43 AM, Aditya Narayan wrote: I think you got it exactly what I wanted to convey except for few things I want to clarify: I was thinking of a single row containing all reminders ( not split by day). History of the reminders need to be maintained for some time. After certain time (say 3 or 6 months) they may be deleted by ttl facility. While presenting the reminders timeline to the user, latest supercolumns like around 50 from the start_end will be picked up and their subcolumns values will be compared to the Tags user has chosen to see and, corresponding to the filtered subcolumn values(tags), the rows of the reminder details would be picked up.. Is supercolumn a preferable choice for this ? Can there be a better schema than this ? -Aditya Narayan On Wed, Feb 2, 2011 at 8:54 PM, William R Speirsbill.spe...@gmail.com wrote: To reiterate, so I know we're both on the same page, your schema would be something like this: - A column family (as you describe) to store the details of a reminder. One reminder per row. The row key would be a TimeUUID. - A super column family to store the reminders for each user, for each day. The row key would be something like: MMDD:user_id. The column names would simply be the TimeUUID of the messages. The sub column names would be the tag names of the various reminders. The idea is that you would then get a slice of each row for a user, for a day, that would only contain sub column names with the tags you're looking for? Then based upon the column names returned, you'd look-up the reminders. That seems like a solid schema to me. Bill- On 02/02/2011 09:37 AM, Aditya Narayan wrote: Actually, I am trying to use Cassandra to display to users on my applicaiton, the list of all Reminders set by themselves for themselves, on the application. I need to store rows containing the timeline of daily Reminders put by the users, for themselves, on application. The reminders need to be presented to the user in a chronological order like a news feed. Each reminder has got certain tags associated with it(so that, at times, user may also choose to see the reminders filtered by tags in chronological order). So I thought of a schema something like this:- -Each Reminder details may be stored as separate rows in column family. -For presenting the timeline
Re: Schema Design Question : Supercolumn family or just a Standard column family with columns containing serialized aggregate data?
On Wed, Feb 2, 2011 at 3:27 PM, Aditya Narayan ady...@gmail.com wrote: Can I have some more feedback about my schema perhaps somewhat more criticisive/harsh ? It sounds reasonable to me. Since you're writing/reading all of the subcolumns at the same time, I would opt for a standard column with the tags serialized into a column value. I don't think you need to worry about row lengths here. Depending on the reminder size and how many times it's likely to be repeated in the timeline, you could explore denormalizing a bit more by storing the reminders in the timelines themselves, perhaps with a separate row per (user, tag) combination. This would cut down on your seeks quite a bit, but it may not be necessary at this point (or at all). -- Tyler Hobbs Software Engineer, DataStax http://datastax.com/ Maintainer of the pycassa http://github.com/pycassa/pycassa Cassandra Python client library
