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POQuery plan for database table containing trillions of records
 

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  1. POQuery plan for database table containing trillions of records
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    <p>I have a big table containing trillions of records of the following schema (Here serial no. is the key):</p> <pre><code> MyTable Column | Type | Modifiers ----------- +--------------------------+----------- serial_number | int | name | character varying(255) | Designation | character varying(255) | place | character varying(255) | timeOfJoining | timestamp with time zone | timeOfLeaving | timestamp with time zone | </code></pre> <p>Now I want to fire queries of the form given below on this table:</p> <pre><code>select place from myTable where Designation='Manager' and timeOfJoining&gt;'1930-10-10' and timeOfLeaving&lt;'1950-10-10'; </code></pre> <p>My aim is to achieve fast query execution times. Since, I am designing my own database from scratch, therefore I have the following options. Please guide me as to which one of the two options will be faster.</p> <ol> <li><p>Create 2 separate table. Here, table1 contains the schema (serial_no, name, Designation, place) and table 2 contains the schema (serial_no, timeOfJoining, timeOfLeaving). And then perform a merge join between the two tables. Here, serial_no is the key in both the tables</p></li> <li><p>Keep one single table MyTable. And run the following plan: Create an index Designation_place_name and using the Designation_place_name index, find rows that fit the index condition relation = 'Manager'(The rows on disc are accessed randomly) and then using the filter function keep only rows that match the timeOfJoining criteria.</p></li> </ol> <p>Please help me figure out which one will be faster. It'll be great if you could also tell me the respective pros and cons.</p> <p>EDIT: I intend to use my table as read-only.</p>
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    1. USRose Beck
    1. USRose Beck
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    1. CODon't miss the tsrange type, if you've still the option of changing the schema like that: http://www.postgresql.org/docs/9.2/static/rangetypes.html -- they allow to be indexed efficiently using e.g. GIST indexes.
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      1. USDenis de Bernardy
    2. COBy the information you gave I see no reason for splitting the tables. Unless splitting them allows you to reduce the total amount of data (i.e. remove duplication) that is. As for what is the best solution for your problem, that also depends on how you use it (read-only? lots of updates? lots of inserts?)
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      1. USWolph
    3. COAssuming you will only be querying 1 designation at a time, you could consider partitioning based on that.
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