<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title> examples.performance.short_selects — SQLAlchemy 1.2 Documentation </title> <!-- begin iterate through site-imported + sphinx environment css_files --> <link rel="stylesheet" href="../../../_static/pygments.css" type="text/css" /> <link rel="stylesheet" href="../../../_static/docs.css" type="text/css" /> <link rel="stylesheet" href="../../../_static/changelog.css" type="text/css" /> <link rel="stylesheet" href="../../../_static/sphinx_paramlinks.css" type="text/css" /> <!-- end iterate through site-imported + sphinx environment css_files --> <!-- begin layout.mako headers --> <link rel="index" title="Index" href="../../../genindex.html" /> <link rel="search" title="Search" href="../../../search.html" /> <link rel="copyright" title="Copyright" href="../../../copyright.html" /> <link rel="top" title="SQLAlchemy 1.2 Documentation" href="../../../index.html" /> <link rel="up" title="Module code" href="../../index.html" /> <!-- end layout.mako headers --> </head> <body> <div id="docs-container"> <div id="docs-top-navigation-container" class="body-background"> <div id="docs-header"> <div id="docs-version-header"> Release: <span class="version-num">1.2.19</span> | Release Date: April 15, 2019 </div> <h1>SQLAlchemy 1.2 Documentation</h1> </div> </div> <div id="docs-body-container"> <div id="fixed-sidebar" class=""> <div id="index-nav"> <form class="search" action="../../../search.html" method="get"> <label> Search terms: <input type="text" placeholder="search..." name="q" size="12" /> </label> <input type="submit" value="Search" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p> <a href="../../../contents.html">Contents</a> | <a href="../../../genindex.html">Index</a> </p> </div> </div> <div id="docs-body" class="" > <h1>Source code for examples.performance.short_selects</h1><div class="highlight"><pre> <span></span><span class="sd">"""This series of tests illustrates different ways to SELECT a single</span> <span class="sd">record by primary key</span> <span class="sd">"""</span> <span class="kn">import</span> <span class="nn">random</span> <span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">bindparam</span> <span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">Column</span> <span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">create_engine</span> <span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">Integer</span> <span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">select</span> <span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">String</span> <span class="kn">from</span> <span class="nn">sqlalchemy.ext</span> <span class="k">import</span> <span class="n">baked</span> <span class="kn">from</span> <span class="nn">sqlalchemy.ext.declarative</span> <span class="k">import</span> <span class="n">declarative_base</span> <span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">deferred</span> <span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">Session</span> <span class="kn">from</span> <span class="nn">.</span> <span class="k">import</span> <span class="n">Profiler</span> <span class="n">Base</span> <span class="o">=</span> <span class="n">declarative_base</span><span class="p">()</span> <span class="n">engine</span> <span class="o">=</span> <span class="kc">None</span> <span class="n">ids</span> <span class="o">=</span> <span class="nb">range</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">11000</span><span class="p">)</span> <span class="k">class</span> <span class="nc">Customer</span><span class="p">(</span><span class="n">Base</span><span class="p">):</span> <span class="n">__tablename__</span> <span class="o">=</span> <span class="s2">"customer"</span> <span class="nb">id</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">,</span> <span class="n">primary_key</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span> <span class="n">name</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">String</span><span class="p">(</span><span class="mi">255</span><span class="p">))</span> <span class="n">description</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">String</span><span class="p">(</span><span class="mi">255</span><span class="p">))</span> <span class="n">q</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">)</span> <span class="n">p</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">)</span> <span class="n">x</span> <span class="o">=</span> <span class="n">deferred</span><span class="p">(</span><span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">))</span> <span class="n">y</span> <span class="o">=</span> <span class="n">deferred</span><span class="p">(</span><span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">))</span> <span class="n">z</span> <span class="o">=</span> <span class="n">deferred</span><span class="p">(</span><span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">))</span> <span class="n">Profiler</span><span class="o">.</span><span class="n">init</span><span class="p">(</span><span class="s2">"short_selects"</span><span class="p">,</span> <span class="n">num</span><span class="o">=</span><span class="mi">10000</span><span class="p">)</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">setup</span> <span class="k">def</span> <span class="nf">setup_database</span><span class="p">(</span><span class="n">dburl</span><span class="p">,</span> <span class="n">echo</span><span class="p">,</span> <span class="n">num</span><span class="p">):</span> <span class="k">global</span> <span class="n">engine</span> <span class="n">engine</span> <span class="o">=</span> <span class="n">create_engine</span><span class="p">(</span><span class="n">dburl</span><span class="p">,</span> <span class="n">echo</span><span class="o">=</span><span class="n">echo</span><span class="p">)</span> <span class="n">Base</span><span class="o">.</span><span class="n">metadata</span><span class="o">.</span><span class="n">drop_all</span><span class="p">(</span><span class="n">engine</span><span class="p">)</span> <span class="n">Base</span><span class="o">.</span><span class="n">metadata</span><span class="o">.</span><span class="n">create_all</span><span class="p">(</span><span class="n">engine</span><span class="p">)</span> <span class="n">sess</span> <span class="o">=</span> <span class="n">Session</span><span class="p">(</span><span class="n">engine</span><span class="p">)</span> <span class="n">sess</span><span class="o">.</span><span class="n">add_all</span><span class="p">(</span> <span class="p">[</span> <span class="n">Customer</span><span class="p">(</span> <span class="nb">id</span><span class="o">=</span><span class="n">i</span><span class="p">,</span> <span class="n">name</span><span class="o">=</span><span class="s2">"c</span><span class="si">%d</span><span class="s2">"</span> <span class="o">%</span> <span class="n">i</span><span class="p">,</span> <span class="n">description</span><span class="o">=</span><span class="s2">"c</span><span class="si">%d</span><span class="s2">"</span> <span class="o">%</span> <span class="n">i</span><span class="p">,</span> <span class="n">q</span><span class="o">=</span><span class="n">i</span> <span class="o">*</span> <span class="mi">10</span><span class="p">,</span> <span class="n">p</span><span class="o">=</span><span class="n">i</span> <span class="o">*</span> <span class="mi">20</span><span class="p">,</span> <span class="n">x</span><span class="o">=</span><span class="n">i</span> <span class="o">*</span> <span class="mi">30</span><span class="p">,</span> <span class="n">y</span><span class="o">=</span><span class="n">i</span> <span class="o">*</span> <span class="mi">40</span><span class="p">,</span> <span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">ids</span> <span class="p">]</span> <span class="p">)</span> <span class="n">sess</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">profile</span> <span class="k">def</span> <span class="nf">test_orm_query</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="sd">"""test a straight ORM query of the full entity."""</span> <span class="n">session</span> <span class="o">=</span> <span class="n">Session</span><span class="p">(</span><span class="n">bind</span><span class="o">=</span><span class="n">engine</span><span class="p">)</span> <span class="k">for</span> <span class="n">id_</span> <span class="ow">in</span> <span class="n">random</span><span class="o">.</span><span class="n">sample</span><span class="p">(</span><span class="n">ids</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span> <span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Customer</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">id_</span><span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">profile</span> <span class="k">def</span> <span class="nf">test_orm_query_cols_only</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="sd">"""test an ORM query of only the entity columns."""</span> <span class="n">session</span> <span class="o">=</span> <span class="n">Session</span><span class="p">(</span><span class="n">bind</span><span class="o">=</span><span class="n">engine</span><span class="p">)</span> <span class="k">for</span> <span class="n">id_</span> <span class="ow">in</span> <span class="n">random</span><span class="o">.</span><span class="n">sample</span><span class="p">(</span><span class="n">ids</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span> <span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span><span class="p">,</span> <span class="n">Customer</span><span class="o">.</span><span class="n">name</span><span class="p">,</span> <span class="n">Customer</span><span class="o">.</span><span class="n">description</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span> <span class="n">Customer</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">id_</span> <span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">profile</span> <span class="k">def</span> <span class="nf">test_baked_query</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="sd">"""test a baked query of the full entity."""</span> <span class="n">bakery</span> <span class="o">=</span> <span class="n">baked</span><span class="o">.</span><span class="n">bakery</span><span class="p">()</span> <span class="n">s</span> <span class="o">=</span> <span class="n">Session</span><span class="p">(</span><span class="n">bind</span><span class="o">=</span><span class="n">engine</span><span class="p">)</span> <span class="k">for</span> <span class="n">id_</span> <span class="ow">in</span> <span class="n">random</span><span class="o">.</span><span class="n">sample</span><span class="p">(</span><span class="n">ids</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span> <span class="n">q</span> <span class="o">=</span> <span class="n">bakery</span><span class="p">(</span><span class="k">lambda</span> <span class="n">s</span><span class="p">:</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Customer</span><span class="p">))</span> <span class="n">q</span> <span class="o">+=</span> <span class="k">lambda</span> <span class="n">q</span><span class="p">:</span> <span class="n">q</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">bindparam</span><span class="p">(</span><span class="s2">"id"</span><span class="p">))</span> <span class="n">q</span><span class="p">(</span><span class="n">s</span><span class="p">)</span><span class="o">.</span><span class="n">params</span><span class="p">(</span><span class="nb">id</span><span class="o">=</span><span class="n">id_</span><span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">profile</span> <span class="k">def</span> <span class="nf">test_baked_query_cols_only</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="sd">"""test a baked query of only the entity columns."""</span> <span class="n">bakery</span> <span class="o">=</span> <span class="n">baked</span><span class="o">.</span><span class="n">bakery</span><span class="p">()</span> <span class="n">s</span> <span class="o">=</span> <span class="n">Session</span><span class="p">(</span><span class="n">bind</span><span class="o">=</span><span class="n">engine</span><span class="p">)</span> <span class="k">for</span> <span class="n">id_</span> <span class="ow">in</span> <span class="n">random</span><span class="o">.</span><span class="n">sample</span><span class="p">(</span><span class="n">ids</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span> <span class="n">q</span> <span class="o">=</span> <span class="n">bakery</span><span class="p">(</span> <span class="k">lambda</span> <span class="n">s</span><span class="p">:</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span><span class="p">,</span> <span class="n">Customer</span><span class="o">.</span><span class="n">name</span><span class="p">,</span> <span class="n">Customer</span><span class="o">.</span><span class="n">description</span><span class="p">)</span> <span class="p">)</span> <span class="n">q</span> <span class="o">+=</span> <span class="k">lambda</span> <span class="n">q</span><span class="p">:</span> <span class="n">q</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">bindparam</span><span class="p">(</span><span class="s2">"id"</span><span class="p">))</span> <span class="n">q</span><span class="p">(</span><span class="n">s</span><span class="p">)</span><span class="o">.</span><span class="n">params</span><span class="p">(</span><span class="nb">id</span><span class="o">=</span><span class="n">id_</span><span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">profile</span> <span class="k">def</span> <span class="nf">test_core_new_stmt_each_time</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="sd">"""test core, creating a new statement each time."""</span> <span class="k">with</span> <span class="n">engine</span><span class="o">.</span><span class="n">connect</span><span class="p">()</span> <span class="k">as</span> <span class="n">conn</span><span class="p">:</span> <span class="k">for</span> <span class="n">id_</span> <span class="ow">in</span> <span class="n">random</span><span class="o">.</span><span class="n">sample</span><span class="p">(</span><span class="n">ids</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span> <span class="n">stmt</span> <span class="o">=</span> <span class="n">select</span><span class="p">([</span><span class="n">Customer</span><span class="o">.</span><span class="n">__table__</span><span class="p">])</span><span class="o">.</span><span class="n">where</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">id_</span><span class="p">)</span> <span class="n">row</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="n">stmt</span><span class="p">)</span><span class="o">.</span><span class="n">first</span><span class="p">()</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">row</span><span class="p">)</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">profile</span> <span class="k">def</span> <span class="nf">test_core_reuse_stmt</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="sd">"""test core, reusing the same statement (but recompiling each time)."""</span> <span class="n">stmt</span> <span class="o">=</span> <span class="n">select</span><span class="p">([</span><span class="n">Customer</span><span class="o">.</span><span class="n">__table__</span><span class="p">])</span><span class="o">.</span><span class="n">where</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">bindparam</span><span class="p">(</span><span class="s2">"id"</span><span class="p">))</span> <span class="k">with</span> <span class="n">engine</span><span class="o">.</span><span class="n">connect</span><span class="p">()</span> <span class="k">as</span> <span class="n">conn</span><span class="p">:</span> <span class="k">for</span> <span class="n">id_</span> <span class="ow">in</span> <span class="n">random</span><span class="o">.</span><span class="n">sample</span><span class="p">(</span><span class="n">ids</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span> <span class="n">row</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="n">stmt</span><span class="p">,</span> <span class="nb">id</span><span class="o">=</span><span class="n">id_</span><span class="p">)</span><span class="o">.</span><span class="n">first</span><span class="p">()</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">row</span><span class="p">)</span> <span class="nd">@Profiler</span><span class="o">.</span><span class="n">profile</span> <span class="k">def</span> <span class="nf">test_core_reuse_stmt_compiled_cache</span><span class="p">(</span><span class="n">n</span><span class="p">):</span> <span class="sd">"""test core, reusing the same statement + compiled cache."""</span> <span class="n">compiled_cache</span> <span class="o">=</span> <span class="p">{}</span> <span class="n">stmt</span> <span class="o">=</span> <span class="n">select</span><span class="p">([</span><span class="n">Customer</span><span class="o">.</span><span class="n">__table__</span><span class="p">])</span><span class="o">.</span><span class="n">where</span><span class="p">(</span><span class="n">Customer</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">bindparam</span><span class="p">(</span><span class="s2">"id"</span><span class="p">))</span> <span class="k">with</span> <span class="n">engine</span><span class="o">.</span><span class="n">connect</span><span class="p">()</span><span class="o">.</span><span class="n">execution_options</span><span class="p">(</span> <span class="n">compiled_cache</span><span class="o">=</span><span class="n">compiled_cache</span> <span class="p">)</span> <span class="k">as</span> <span class="n">conn</span><span class="p">:</span> <span class="k">for</span> <span class="n">id_</span> <span class="ow">in</span> <span class="n">random</span><span class="o">.</span><span class="n">sample</span><span class="p">(</span><span class="n">ids</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span> <span class="n">row</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="n">stmt</span><span class="p">,</span> <span class="nb">id</span><span class="o">=</span><span class="n">id_</span><span class="p">)</span><span class="o">.</span><span class="n">first</span><span class="p">()</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">row</span><span class="p">)</span> <span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">"__main__"</span><span class="p">:</span> <span class="n">Profiler</span><span class="o">.</span><span class="n">main</span><span class="p">()</span></pre></div> </div> </div> <div id="docs-bottom-navigation" class="docs-navigation-links"> <div id="docs-copyright"> © <a href="../../../copyright.html">Copyright</a> 2007-2019, the SQLAlchemy authors and contributors. 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