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 <link rel="stylesheet" href="https://at-ui.github.io/feather-font/css/iconfont.css"><title data-react-helmet="true">Schema Evolution | Apache Hudi</title><meta data-react-helmet="true" name="twitter:card" content="summary_large_image"><meta data-react-helmet="true" property="og:url" content="https://hudi.apache.org/cn/docs/0.11.0/schema_evolution"><meta data-react-helmet="true" name="docsearch:language" content="cn"><meta data-react-helmet="true" name="docsearch:version" content="0.11.0"><meta data-react-helmet="true" name="docsearch:docusaurus_tag" content="docs-default-0.11.0"><meta data-react-helmet="true" property="og:title" content="Schema Evolution | Apache Hudi"><meta data-react-helmet="true" name="description" content="Schema evolution allows users to easily change the current schema of a Hudi table to adapt to the data that is changing over time."><meta data-react-helmet="true" property="og:description" content="Schema evolution allows users to easily change the current schema of a Hudi table to adapt to the data that is changing over time."><meta data-react-helmet="true" name="keywords" content="hudi,incremental,batch,stream,processing,schema,evolution"><link data-react-helmet="true" rel="icon" href="/cn/assets/images/favicon.ico"><link data-react-helmet="true" rel="canonical" href="https://hudi.apache.org/cn/docs/0.11.0/schema_evolution"><link data-react-helmet="true" rel="alternate" href="https://hudi.apache.org/docs/0.11.0/schema_evolution" hreflang="en"><link data-react-helmet="true" rel="alternate" href="https://hudi.apache.org/cn/docs/0.11.0/schema_evolution" hreflang="cn"><link data-react-helmet="true" rel="alternate" href="https://hudi.apache.org/docs/0.11.0/schema_evolution" hreflang="x-default"><link data-react-helmet="true" rel="preconnect" href="https://BH4D9OD16A-dsn.algolia.net" crossorigin="anonymous"><link rel="stylesheet" href="/cn/assets/css/styles.052701b1.css">
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theme-doc-sidebar-item-link-level-1 menu__list-item"><a class="menu__link" href="/cn/docs/0.11.0/privacy">Privacy Policy</a></li></ul></nav></div></aside><main class="docMainContainer_Q970"><div class="container padding-top--md padding-bottom--lg"><div class="row"><div class="col docItemCol_zHA2"><div class="theme-doc-version-banner alert alert--warning margin-bottom--md" role="alert"><div>This is documentation for <!-- -->Apache Hudi<!-- --> <b>0.11.0</b>, which is no longer actively maintained.</div><div class="margin-top--md">For up-to-date documentation, see the <b><a href="/cn/docs/schema_evolution">latest version</a></b> (<!-- -->0.14.1<!-- -->).</div></div><div class="docItemContainer_oiyr"><article><span class="theme-doc-version-badge badge badge--secondary">Version: <!-- -->0.11.0</span><div class="tocCollapsible_aw-L theme-doc-toc-mobile tocMobile_Tx6Y"><button type="button" class="clean-btn tocCollapsibleButton_zr6a">On this page</button></div><div class="theme-doc-markdown markdown"><header><h1>Schema Evolution</h1></header><p>Schema evolution allows users to easily change the current schema of a Hudi table to adapt to the data that is changing over time.
 As of 0.11.0 release, Spark SQL (Spark 3.1.x, 3.2.1 and above) DDL support for Schema  evolution has been added and is experimental.</p><h3 class="anchor anchorWithStickyNavbar_y2LR" id="scenarios">Scenarios<a class="hash-link" href="#scenarios" title="Direct link to heading"></a></h3><ol><li>Columns (including nested columns) can be added, deleted, modified, and moved.</li><li>Partition columns cannot be evolved.</li><li>You cannot add, delete, or perform operations on nested columns of the Array type.</li></ol><h2 class="anchor anchorWithStickyNavbar_y2LR" id="sparksql-schema-evolution-and-syntax-description">SparkSQL Schema Evolution and Syntax Description<a class="hash-link" href="#sparksql-schema-evolution-and-syntax-description" title="Direct link to heading"></a></h2><p>Before using schema evolution, pls set <code>spark.sql.extensions</code>. For Spark 3.2.1 and above, <code>spark.sql.catalog.spark_catalog</code> also need to be set.</p><div class="codeBlockContainer_J+bg language-shell theme-code-block"><div class="codeBlockContent_csEI shell"><pre tabindex="0" class="prism-code language-shell codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)"># Spark SQL for spark 3.1.x</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">spark-sql --packages org.apache.hudi:hudi-spark3.1.2-bundle_2.12:0.11.1 </span><span class="token punctuation" style="color:rgb(248, 248, 242)">\</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">--conf </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;spark.serializer=org.apache.spark.serializer.KryoSerializer&#x27;</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(248, 248, 242)">\</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">--conf </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;spark.sql.extensions=org.apache.spark.sql.hudi.HoodieSparkSessionExtension&#x27;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token comment" style="color:rgb(98, 114, 164)"># Spark SQL for spark 3.2.1 and above</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">spark-sql --packages org.apache.hudi:hudi-spark3-bundle_2.12:0.11.1 </span><span class="token punctuation" style="color:rgb(248, 248, 242)">\</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">--conf </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;spark.serializer=org.apache.spark.serializer.KryoSerializer&#x27;</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(248, 248, 242)">\</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">--conf </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;spark.sql.extensions=org.apache.spark.sql.hudi.HoodieSparkSessionExtension&#x27;</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(248, 248, 242)">\</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">--conf </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;spark.sql.catalog.spark_catalog=org.apache.spark.sql.hudi.catalog.HoodieCatalog&#x27;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p>After start spark-app,  pls exec <code>set hoodie.schema.on.read.enable=true</code> to enable schema evolution.</p><div class="admonition admonition-note alert alert--secondary"><div class="admonition-heading"><h5><span class="admonition-icon"><svg xmlns="http://www.w3.org/2000/svg" width="14" height="16" viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg></span>note</h5></div><div class="admonition-content"><p>Currently, Schema evolution cannot disabled once being enabled.</p></div></div><div class="admonition admonition-tip alert alert--success"><div class="admonition-heading"><h5><span class="admonition-icon"><svg xmlns="http://www.w3.org/2000/svg" width="12" height="16" viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>tip</h5></div><div class="admonition-content"><p>When use hive metastore, may encounter a problem: <code>org.apache.hadoop.hive.ql.metadata.HiveException</code>: Unable to alter table. The following columns have types incompatible with the existing columns in their respective positions.</p><p>Make sure disable <code>hive.metastore.disallow.incompatible.col.type.changes</code> in hive side.</p></div></div><h3 class="anchor anchorWithStickyNavbar_y2LR" id="adding-columns">Adding Columns<a class="hash-link" href="#adding-columns" title="Direct link to heading"></a></h3><p><strong>Syntax</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)">-- add columns</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> tableName </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ADD</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMNS</span><span class="token punctuation" style="color:rgb(248, 248, 242)">(</span><span class="token plain">col_spec</span><span class="token punctuation" style="color:rgb(248, 248, 242)">[</span><span class="token punctuation" style="color:rgb(248, 248, 242)">,</span><span class="token plain"> col_spec </span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token punctuation" style="color:rgb(248, 248, 242)">]</span><span class="token punctuation" style="color:rgb(248, 248, 242)">)</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p><strong>Parameter Description</strong></p><table><thead><tr><th align="left">Parameter</th><th align="left">Description</th></tr></thead><tbody><tr><td align="left">tableName</td><td align="left">Table name</td></tr><tr><td align="left">col_spec</td><td align="left">Column specifications, consisting of five fields, <em>col_name</em>, <em>col_type</em>, <em>nullable</em>, <em>comment</em>, and <em>col_position</em>.</td></tr></tbody></table><p><strong>col_name</strong> : name of the new column. It is mandatory.To add a sub-column to a nested column, specify the full name of the sub-column in this field.</p><p>For example:</p><ol><li><p>To add sub-column col1 to a nested struct type column column users struct&lt;name: string, age: int&gt;, set this field to users.col1.</p></li><li><p>To add sub-column col1 to a nested map type column memeber map&lt;string, struct&lt;n: string, a: int&gt;&gt;, set this field to member.value.col1.</p></li></ol><p><strong>col_type</strong> : type of the new column.</p><p><strong>nullable</strong> : whether the new column can be null. The value can be left empty. Now this field is not used in Hudi.</p><p><strong>comment</strong> : comment of the new column. The value can be left empty.</p><p><strong>col_position</strong> : position where the new column is added. The value can be <em>FIRST</em> or <em>AFTER</em> origin_col.</p><ol><li><p>If it is set to <em>FIRST</em>, the new column will be added to the first column of the table.</p></li><li><p>If it is set to <em>AFTER</em> origin_col, the new column will be added after original column origin_col.</p></li><li><p>The value can be left empty. <em>FIRST</em> can be used only when new sub-columns are added to nested columns. Do not use <em>FIRST</em> in top-level columns. There are no restrictions about the usage of <em>AFTER</em>.</p></li></ol><p><strong>Examples</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> h0 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ADD</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMNS</span><span class="token punctuation" style="color:rgb(248, 248, 242)">(</span><span class="token plain">ext0 string</span><span class="token punctuation" style="color:rgb(248, 248, 242)">)</span><span class="token punctuation" style="color:rgb(248, 248, 242)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> h0 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ADD</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMNS</span><span class="token punctuation" style="color:rgb(248, 248, 242)">(</span><span class="token plain">new_col </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">int</span><span class="token plain"> </span><span class="token operator">not</span><span class="token plain"> </span><span class="token boolean">null</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">comment</span><span class="token plain"> </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;add new column&#x27;</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">AFTER</span><span class="token plain"> col1</span><span class="token punctuation" style="color:rgb(248, 248, 242)">)</span><span class="token punctuation" style="color:rgb(248, 248, 242)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> complex_table </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ADD</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMNS</span><span class="token punctuation" style="color:rgb(248, 248, 242)">(</span><span class="token plain">col_struct</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">col_name string </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">comment</span><span class="token plain"> </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;add new column to a struct col&#x27;</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">AFTER</span><span class="token plain"> col_from_col_struct</span><span class="token punctuation" style="color:rgb(248, 248, 242)">)</span><span class="token punctuation" style="color:rgb(248, 248, 242)">;</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><h3 class="anchor anchorWithStickyNavbar_y2LR" id="altering-columns">Altering Columns<a class="hash-link" href="#altering-columns" title="Direct link to heading"></a></h3><p><strong>Syntax</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)">-- alter table ... alter column</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> tableName </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(248, 248, 242)">[</span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token punctuation" style="color:rgb(248, 248, 242)">]</span><span class="token plain"> col_old_name </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TYPE</span><span class="token plain"> column_type </span><span class="token punctuation" style="color:rgb(248, 248, 242)">[</span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COMMENT</span><span class="token punctuation" style="color:rgb(248, 248, 242)">]</span><span class="token plain"> col_comment</span><span class="token punctuation" style="color:rgb(248, 248, 242)">[</span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">FIRST</span><span class="token operator">|</span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">AFTER</span><span class="token punctuation" style="color:rgb(248, 248, 242)">]</span><span class="token plain"> column_name</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p><strong>Parameter Description</strong></p><table><thead><tr><th align="left">Parameter</th><th align="left">Description</th></tr></thead><tbody><tr><td align="left">tableName</td><td align="left">Table name.</td></tr><tr><td align="left">col_old_name</td><td align="left">Name of the column to be altered.</td></tr><tr><td align="left">column_type</td><td align="left">Type of the target column.</td></tr><tr><td align="left">col_comment</td><td align="left">col_comment.</td></tr><tr><td align="left">column_name</td><td align="left">New position to place the target column. For example, <em>AFTER</em> <strong>column_name</strong> indicates that the target column is placed after <strong>column_name</strong>.</td></tr></tbody></table><p><strong>Examples</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)">--- Changing the column type</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TYPE</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">bigint</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token comment" style="color:rgb(98, 114, 164)">--- Altering other attributes</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COMMENT</span><span class="token plain"> </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;new comment&#x27;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">FIRST</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">AFTER</span><span class="token plain"> x</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">DROP</span><span class="token plain"> </span><span class="token operator">NOT</span><span class="token plain"> </span><span class="token boolean">NULL</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p><strong>column type change</strong></p><table><thead><tr><th>Source\Target</th><th>long</th><th>float</th><th>double</th><th>string</th><th>decimal</th><th>date</th><th>int</th></tr></thead><tbody><tr><td>int</td><td>Y</td><td>Y</td><td>Y</td><td>Y</td><td>Y</td><td>N</td><td>Y</td></tr><tr><td>long</td><td>Y</td><td>Y</td><td>Y</td><td>Y</td><td>Y</td><td>N</td><td>N</td></tr><tr><td>float</td><td>N</td><td>Y</td><td>Y</td><td>Y</td><td>Y</td><td>N</td><td>N</td></tr><tr><td>double</td><td>N</td><td>N</td><td>Y</td><td>Y</td><td>Y</td><td>N</td><td>N</td></tr><tr><td>decimal</td><td>N</td><td>N</td><td>N</td><td>Y</td><td>Y</td><td>N</td><td>N</td></tr><tr><td>string</td><td>N</td><td>N</td><td>N</td><td>Y</td><td>Y</td><td>Y</td><td>N</td></tr><tr><td>date</td><td>N</td><td>N</td><td>N</td><td>Y</td><td>N</td><td>Y</td><td>N</td></tr></tbody></table><h3 class="anchor anchorWithStickyNavbar_y2LR" id="deleting-columns">Deleting Columns<a class="hash-link" href="#deleting-columns" title="Direct link to heading"></a></h3><p><strong>Syntax</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)">-- alter table ... drop columns</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> tableName </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">DROP</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token operator">|</span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMNS</span><span class="token plain"> cols</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p><strong>Examples</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">DROP</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">DROP</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMNS</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c</span><span class="token punctuation" style="color:rgb(248, 248, 242)">,</span><span class="token plain"> x</span><span class="token punctuation" style="color:rgb(248, 248, 242)">,</span><span class="token plain"> y</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><h3 class="anchor anchorWithStickyNavbar_y2LR" id="changing-column-name">Changing Column Name<a class="hash-link" href="#changing-column-name" title="Direct link to heading"></a></h3><p><strong>Syntax</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)">-- alter table ... rename column</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> tableName </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">RENAME</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> old_columnName </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TO</span><span class="token plain"> new_columnName</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p><strong>Examples</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">RENAME</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">COLUMN</span><span class="token plain"> a</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">b</span><span class="token punctuation" style="color:rgb(248, 248, 242)">.</span><span class="token plain">c </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TO</span><span class="token plain"> x</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><h3 class="anchor anchorWithStickyNavbar_y2LR" id="modifying-table-properties">Modifying Table Properties<a class="hash-link" href="#modifying-table-properties" title="Direct link to heading"></a></h3><p><strong>Syntax</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)">-- alter table ... set|unset</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> tableName </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">SET</span><span class="token operator">|</span><span class="token plain">UNSET tblproperties</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p><strong>Examples</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">table</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">SET</span><span class="token plain"> TBLPROPERTIES </span><span class="token punctuation" style="color:rgb(248, 248, 242)">(</span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;table_property&#x27;</span><span class="token plain"> </span><span class="token operator">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;property_value&#x27;</span><span class="token punctuation" style="color:rgb(248, 248, 242)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">table</span><span class="token plain"> UNSET TBLPROPERTIES </span><span class="token punctuation" style="color:rgb(248, 248, 242)">[</span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">IF</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">EXISTS</span><span class="token punctuation" style="color:rgb(248, 248, 242)">]</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(248, 248, 242)">(</span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;comment&#x27;</span><span class="token punctuation" style="color:rgb(248, 248, 242)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(255, 121, 198)">&#x27;key&#x27;</span><span class="token punctuation" style="color:rgb(248, 248, 242)">)</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><h3 class="anchor anchorWithStickyNavbar_y2LR" id="changing-a-table-name">Changing a Table Name<a class="hash-link" href="#changing-a-table-name" title="Direct link to heading"></a></h3><p><strong>Syntax</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token comment" style="color:rgb(98, 114, 164)">-- alter table ... rename</span><span class="token plain"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain"></span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> tableName </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">RENAME</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TO</span><span class="token plain"> newTableName</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><p><strong>Examples</strong></p><div class="codeBlockContainer_J+bg language-sql theme-code-block"><div class="codeBlockContent_csEI sql"><pre tabindex="0" class="prism-code language-sql codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">ALTER</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TABLE</span><span class="token plain"> table1 </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">RENAME</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(189, 147, 249);font-style:italic">TO</span><span class="token plain"> table2</span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div><h2 class="anchor anchorWithStickyNavbar_y2LR" id="schema-evolution-pre-0110">Schema Evolution Pre-0.11.0<a class="hash-link" href="#schema-evolution-pre-0110" title="Direct link to heading"></a></h2><p>Schema evolution is a very important aspect of data management.
 Hudi supports common schema evolution scenarios, such as adding a nullable field or promoting a datatype of a field, out-of-the-box.
 Furthermore, the evolved schema is queryable across engines, such as Presto, Hive and Spark SQL.
 The following table presents a summary of the types of schema changes compatible with different Hudi table types.</p><table><thead><tr><th align="left">Schema Change</th><th align="left">COW</th><th align="left">MOR</th><th align="left">Remarks</th></tr></thead><tbody><tr><td align="left">Add a new nullable column at root level at the end</td><td align="left">Yes</td><td align="left">Yes</td><td align="left"><code>Yes</code> means that a write with evolved schema succeeds and a read following the write succeeds to read entire dataset.</td></tr><tr><td align="left">Add a new nullable column to inner struct (at the end)</td><td align="left">Yes</td><td align="left">Yes</td><td align="left"></td></tr><tr><td align="left">Add a new complex type field with default (map and array)</td><td align="left">Yes</td><td align="left">Yes</td><td align="left"></td></tr><tr><td align="left">Add a new nullable column and change the ordering of fields</td><td align="left">No</td><td align="left">No</td><td align="left">Write succeeds but read fails if the write with evolved schema updated only some of the base files but not all. Currently, Hudi does not maintain a schema registry with history of changes across base files. Nevertheless, if the upsert touched all base files then the read will succeed.</td></tr><tr><td align="left">Add a custom nullable Hudi meta column, e.g. <code>_hoodie_meta_col</code></td><td align="left">Yes</td><td align="left">Yes</td><td align="left"></td></tr><tr><td align="left">Promote datatype from <code>int</code> to <code>long</code> for a field at root level</td><td align="left">Yes</td><td align="left">Yes</td><td align="left">For other types, Hudi supports promotion as specified in <a href="http://avro.apache.org/docs/current/spec#Schema+Resolution" target="_blank" rel="noopener noreferrer">Avro schema resolution</a>.</td></tr><tr><td align="left">Promote datatype from <code>int</code> to <code>long</code> for a nested field</td><td align="left">Yes</td><td align="left">Yes</td><td align="left"></td></tr><tr><td align="left">Promote datatype from <code>int</code> to <code>long</code> for a complex type (value of map or array)</td><td align="left">Yes</td><td align="left">Yes</td><td align="left"></td></tr><tr><td align="left">Add a new non-nullable column at root level at the end</td><td align="left">No</td><td align="left">No</td><td align="left">In case of MOR table with Spark data source, write succeeds but read fails. As a <strong>workaround</strong>, you can make the field nullable.</td></tr><tr><td align="left">Add a new non-nullable column to inner struct (at the end)</td><td align="left">No</td><td align="left">No</td><td align="left"></td></tr><tr><td align="left">Change datatype from <code>long</code> to <code>int</code> for a nested field</td><td align="left">No</td><td align="left">No</td><td align="left"></td></tr><tr><td align="left">Change datatype from <code>long</code> to <code>int</code> for a complex type (value of map or array)</td><td align="left">No</td><td align="left">No</td><td align="left"></td></tr></tbody></table><p>Let us walk through an example to demonstrate the schema evolution support in Hudi.
 In the below example, we are going to add a new string field and change the datatype of a field from int to long.</p><div class="codeBlockContainer_J+bg language-java theme-code-block"><div class="codeBlockContent_csEI java"><pre tabindex="0" class="prism-code language-java codeBlock_rtdJ thin-scrollbar" style="color:#F8F8F2;background-color:#282A36"><code class="codeBlockLines_1zSZ"><span class="token-line" style="color:#F8F8F2"><span class="token plain">Welcome to</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    ____              __</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    / __/__  ___ _____/ /__</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    _\ \/ _ \/ _ `/ __/  &#x27;_/</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    /___/ .__/\_,_/_/ /_/\_\   version 3.1.2</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    /_/</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    Using Scala version 2.12.10 (OpenJDK 64-Bit Server VM, Java 1.8.0_292)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    Type in expressions to have them evaluated.</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    Type :help for more information.</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import org.apache.hudi.QuickstartUtils._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import org.apache.hudi.QuickstartUtils._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import scala.collection.JavaConversions._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import scala.collection.JavaConversions._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import org.apache.spark.sql.SaveMode._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import org.apache.spark.sql.SaveMode._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import org.apache.hudi.DataSourceReadOptions._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import org.apache.hudi.DataSourceReadOptions._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import org.apache.hudi.DataSourceWriteOptions._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import org.apache.hudi.DataSourceWriteOptions._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import org.apache.hudi.config.HoodieWriteConfig._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import org.apache.hudi.config.HoodieWriteConfig._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import org.apache.spark.sql.types._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import org.apache.spark.sql.types._</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; import org.apache.spark.sql.Row</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">import org.apache.spark.sql.Row</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; val tableName = &quot;hudi_trips_cow&quot;</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    tableName: String = hudi_trips_cow</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; val basePath = &quot;file:///tmp/hudi_trips_cow&quot;</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    basePath: String = file:///tmp/hudi_trips_cow</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; val schema = StructType( Array(</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;rowId&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;partitionId&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;preComb&quot;, LongType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;name&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;versionId&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;intToLong&quot;, IntegerType,true)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | ))</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    schema: org.apache.spark.sql.types.StructType = StructType(StructField(rowId,StringType,true), StructField(partitionId,StringType,true), StructField(preComb,LongType,true), StructField(name,StringType,true), StructField(versionId,StringType,true), StructField(intToLong,IntegerType,true))</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    </span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; val data1 = Seq(Row(&quot;row_1&quot;, &quot;part_0&quot;, 0L, &quot;bob&quot;, &quot;v_0&quot;, 0),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |                Row(&quot;row_2&quot;, &quot;part_0&quot;, 0L, &quot;john&quot;, &quot;v_0&quot;, 0),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |                Row(&quot;row_3&quot;, &quot;part_0&quot;, 0L, &quot;tom&quot;, &quot;v_0&quot;, 0))</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    data1: Seq[org.apache.spark.sql.Row] = List([row_1,part_0,0,bob,v_0,0], [row_2,part_0,0,john,v_0,0], [row_3,part_0,0,tom,v_0,0])</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; var dfFromData1 = spark.createDataFrame(data1, schema)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; dfFromData1.write.format(&quot;hudi&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   options(getQuickstartWriteConfigs).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(PRECOMBINE_FIELD.key, &quot;preComb&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(RECORDKEY_FIELD.key, &quot;rowId&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(PARTITIONPATH_FIELD.key, &quot;partitionId&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(&quot;hoodie.index.type&quot;,&quot;SIMPLE&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(TBL_NAME.key, tableName).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   mode(Overwrite).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   save(basePath)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; var tripsSnapshotDF1 = spark.read.format(&quot;hudi&quot;).load(basePath + &quot;/*/*&quot;)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    tripsSnapshotDF1: org.apache.spark.sql.DataFrame = [_hoodie_commit_time: string, _hoodie_commit_seqno: string ... 9 more fields]</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; tripsSnapshotDF1.createOrReplaceTempView(&quot;hudi_trips_snapshot&quot;)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; spark.sql(&quot;desc hudi_trips_snapshot&quot;).show()</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +--------------------+---------+-------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |            col_name|data_type|comment|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +--------------------+---------+-------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | _hoodie_commit_time|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |_hoodie_commit_seqno|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |  _hoodie_record_key|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |_hoodie_partition...|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   _hoodie_file_name|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |               rowId|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |         partitionId|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |             preComb|   bigint|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |                name|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |           versionId|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |           intToLong|      int|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +--------------------+---------+-------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    </span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; spark.sql(&quot;select rowId, partitionId, preComb, name, versionId, intToLong from hudi_trips_snapshot&quot;).show()</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +-----+-----------+-------+----+---------+---------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |rowId|partitionId|preComb|name|versionId|intToLong|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +-----+-----------+-------+----+---------+---------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_3|     part_0|      0| tom|      v_0|        0|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_2|     part_0|      0|john|      v_0|        0|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_1|     part_0|      0| bob|      v_0|        0|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +-----+-----------+-------+----+---------+---------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">// In the new schema, we are going to add a String field and </span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">// change the datatype `intToLong` field from  int to long.</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; val newSchema = StructType( Array(</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;rowId&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;partitionId&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;preComb&quot;, LongType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;name&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;versionId&quot;, StringType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;intToLong&quot;, LongType,true),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | StructField(&quot;newField&quot;, StringType,true)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | ))</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    newSchema: org.apache.spark.sql.types.StructType = StructType(StructField(rowId,StringType,true), StructField(partitionId,StringType,true), StructField(preComb,LongType,true), StructField(name,StringType,true), StructField(versionId,StringType,true), StructField(intToLong,LongType,true), StructField(newField,StringType,true))</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; val data2 = Seq(Row(&quot;row_2&quot;, &quot;part_0&quot;, 5L, &quot;john&quot;, &quot;v_3&quot;, 3L, &quot;newField_1&quot;),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |                Row(&quot;row_5&quot;, &quot;part_0&quot;, 5L, &quot;maroon&quot;, &quot;v_2&quot;, 2L, &quot;newField_1&quot;),</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |                Row(&quot;row_9&quot;, &quot;part_0&quot;, 5L, &quot;michael&quot;, &quot;v_2&quot;, 2L, &quot;newField_1&quot;))</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    data2: Seq[org.apache.spark.sql.Row] = List([row_2,part_0,5,john,v_3,3,newField_1], [row_5,part_0,5,maroon,v_2,2,newField_1], [row_9,part_0,5,michael,v_2,2,newField_1])</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; var dfFromData2 = spark.createDataFrame(data2, newSchema)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; dfFromData2.write.format(&quot;hudi&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   options(getQuickstartWriteConfigs).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(PRECOMBINE_FIELD.key, &quot;preComb&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(RECORDKEY_FIELD.key, &quot;rowId&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(PARTITIONPATH_FIELD.key, &quot;partitionId&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(&quot;hoodie.index.type&quot;,&quot;SIMPLE&quot;).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   option(TBL_NAME.key, tableName).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   mode(Append).</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   save(basePath)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; var tripsSnapshotDF2 = spark.read.format(&quot;hudi&quot;).load(basePath + &quot;/*/*&quot;)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    tripsSnapshotDF2: org.apache.spark.sql.DataFrame = [_hoodie_commit_time: string, _hoodie_commit_seqno: string ... 10 more fields]</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; tripsSnapshotDF2.createOrReplaceTempView(&quot;hudi_trips_snapshot&quot;)</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; spark.sql(&quot;desc hudi_trips_snapshot&quot;).show()</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +--------------------+---------+-------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |            col_name|data_type|comment|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +--------------------+---------+-------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    | _hoodie_commit_time|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |_hoodie_commit_seqno|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |  _hoodie_record_key|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |_hoodie_partition...|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |   _hoodie_file_name|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |               rowId|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |         partitionId|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |             preComb|   bigint|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |                name|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |           versionId|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |           intToLong|   bigint|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |            newField|   string|   null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +--------------------+---------+-------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">scala&gt; spark.sql(&quot;select rowId, partitionId, preComb, name, versionId, intToLong, newField from hudi_trips_snapshot&quot;).show()</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +-----+-----------+-------+-------+---------+---------+----------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |rowId|partitionId|preComb|   name|versionId|intToLong|  newField|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +-----+-----------+-------+-------+---------+---------+----------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_3|     part_0|      0|    tom|      v_0|        0|      null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_2|     part_0|      5|   john|      v_3|        3|newField_1|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_1|     part_0|      0|    bob|      v_0|        0|      null|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_5|     part_0|      5| maroon|      v_2|        2|newField_1|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    |row_9|     part_0|      5|michael|      v_2|        2|newField_1|</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain">    +-----+-----------+-------+-------+---------+---------+----------+</span><br></span><span class="token-line" style="color:#F8F8F2"><span class="token plain" style="display:inline-block"></span><br></span></code></pre><button type="button" aria-label="Copy code to clipboard" class="copyButton_M3SB clean-btn">Copy</button></div></div></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="theme-doc-footer-edit-meta-row row"><div class="col"><a href="https://github.com/apache/hudi/tree/asf-site/website/versioned_docs/version-0.11.0/schema_evolution.md" target="_blank" rel="noreferrer noopener" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_mS5F" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col 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