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| Newsgroups | comp.databases.ms-sqlserver |
| Date | Tue, 29 Sep 2015 12:06:05 -0700 (PDT) |
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| Subject | cluster or hash table advise needed |
| From | "M.G." <michael@gurfinkel.us> |
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| Xref | csiph.com comp.databases.ms-sqlserver:1942 |
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We are designing a table with high insert / delete activity. The table maintains sequence of actions per specific experiments. These are the attributes: CREATE TABLE ACTION_SEQUENCE ( /* ACTION_SEQUENCE_ID int NOT NULL, <<< questionable */ EXP_ID int NOT NULL, ACT_SEQ int NOT NULL, ACT_ID int NOT NULL, MODIFIED_TIME datetime NULL, ACT_TYPE int NOT NULL, ); EXP_ID and ACT_ID are foreign keys into experiments and actions tables correspondingly. sample data for two experiments with 2 action for #100 and three actions for #200: EXP_ID ACT_SEQ ACT_ID ACT_TYPE 100 1 233 0 100 2 560 0 100 3 233 1 200 1 220 0 200 2 220 1 200 3 778 0 200 4 778 1 The nature of EXP_ID - monotonous increment, same for ACT_ID. How we read data - access one experiment at a time, its actions sorted by ACT_SEQ. Like this: select * from ACTION_SEQUENCE where EXP_ID=@ID order by ACT_SEQ; The sequence is of essence here. How we add / update data - use delete/insert approach (never update), again records per one experiment are always deleted (if exists) and inserted as a group, like this: delete from ACTION_SEQUENCE where EXP_ID=@ID; insert into ACTION_SEQUENCE(EXP_ID,ACT_SEQ,ACT_ID) values (@ID,...) Expected number of records - around 10 million, expected number of inserts (pure additions) around 5000 a day, number of change (delete/insert) around 1000 Expected read / write ratio - 10 reads per 1 update The question - would you make it a clustered table. or no cluster at all? Current design - table has ACTION_SEQUENCE_ID primary key (cluster), the sequence itself is maintained through external sequence table (reason - the app development framework). I don't see any need for cluster here (and it's maintenance). We can use EXP_ID, ACT_SEQ, ACT_ID as unique key logically, but again, we never deal with individual records, only with groups of records for a given experiment. Your input is highly appreciated.
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cluster or hash table advise needed "M.G." <michael@gurfinkel.us> - 2015-09-29 12:06 -0700
Re: cluster or hash table advise needed Erland Sommarskog <esquel@sommarskog.se> - 2015-09-29 22:15 +0200
Re: cluster or hash table advise needed "M.G." <michael@gurfinkel.us> - 2015-09-29 13:55 -0700
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