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<div class="textblock"><p>The <code>next_random</code> configuration to the <a class="el" href="struct_w_t___s_e_s_s_i_o_n.html#afb5b4a69c2c5cafe411b2b04fdc1c75d" title="Open a new cursor on a data source or duplicate an existing cursor. ">WT_SESSION::open_cursor</a> method configures the cursor to return a pseudo-random record from a row-store object (the <code>next_random</code> configuration is not supported on other types of objects).</p>
<p>Applications should use the <a class="el" href="struct_w_t___c_u_r_s_o_r.html#a0503f16bd8f3d05aa3552f229b3a8e1b" title="Return the next record. ">WT_CURSOR::next</a> method to retrieve records from the object, most other cursor methods are not supported. For example, it's not possible to update using a cursor configured for random retrieval.</p>
<p>By default, each returned record is pseudo-randomly selected from the underlying object as a whole. That can lead to skewed results when the underlying tree structure is unbalanced or records are not uniformly distributed. In such cases, the <code>next_random_sample_size</code> configuration can also be specified. Setting <code>next_random_sample_size</code> configures the number of samples the application expects to take using the cursor. A cursor configured using <code>next_random_sample_size</code> divides the object into <code>next_random_sample_size</code> pieces, and each subsequent retrieval returns a record from the next one of those pieces.</p>
<p>For example, setting <code>next_random_sample_percent</code> to <code>10</code> would cause the cursor to sequentially return records from each tenth part of the object. Setting <code>next_random_sample_percent</code> to <code>1000</code> would cause the cursor to sequentially return records from each .1% of the object. </p>
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