>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #2375697. --> Reported by: [proteo](https://www.drupal.org/user/2644289) >>> <p>Hi. When using PostgreSQL the following fatal error appears when opening the config screen:</p> <div class="codeblock"> <pre><span style="color: #000000"><span style="color: #0000BB">&lt;?php<br>PDOException</span><span style="color: #007700">: </span><span style="color: #0000BB">SQLSTATE</span><span style="color: #007700">[</span><span style="color: #0000BB">42883</span><span style="color: #007700">]: </span><span style="color: #0000BB">Undefined </span><span style="color: #007700">function: </span><span style="color: #0000BB">7 ERROR</span><span style="color: #007700">: function </span><span style="color: #0000BB">substring_index</span><span style="color: #007700">(</span><span style="color: #0000BB">character varying</span><span style="color: #007700">, </span><span style="color: #0000BB">unknown</span><span style="color: #007700">, </span><span style="color: #0000BB">integer</span><span style="color: #007700">) </span><span style="color: #0000BB">does not exist LINE 1</span><span style="color: #007700">: </span><span style="color: #0000BB">SELECT identifier</span><span style="color: #007700">,</span><span style="color: #0000BB">count</span><span style="color: #007700">(*) </span><span style="color: #0000BB">count</span><span style="color: #007700">,</span><span style="color: #0000BB">SUBSTRING_INDEX</span><span style="color: #007700">(</span><span style="color: #0000BB">identifier</span><span style="color: #007700">,... ^ </span><span style="color: #0000BB">HINT</span><span style="color: #007700">: </span><span style="color: #0000BB">No </span><span style="color: #007700">function </span><span style="color: #0000BB">matches the given name </span><span style="color: #007700">and </span><span style="color: #0000BB">argument types</span><span style="color: #007700">. </span><span style="color: #0000BB">You might need to add explicit type casts</span><span style="color: #007700">.: </span><span style="color: #0000BB">SELECT identifier</span><span style="color: #007700">,</span><span style="color: #0000BB">count</span><span style="color: #007700">(*) </span><span style="color: #0000BB">count</span><span style="color: #007700">,</span><span style="color: #0000BB">SUBSTRING_INDEX</span><span style="color: #007700">(</span><span style="color: #0000BB">identifier</span><span style="color: #007700">, </span><span style="color: #DD0000">'-'</span><span style="color: #007700">,</span><span style="color: #0000BB">1</span><span style="color: #007700">) AS </span><span style="color: #0000BB">uid</span><span style="color: #007700">, </span><span style="color: #0000BB">SUBSTRING_INDEX</span><span style="color: #007700">(</span><span style="color: #0000BB">identifier</span><span style="color: #007700">, </span><span style="color: #DD0000">'-'</span><span style="color: #007700">,-</span><span style="color: #0000BB">1</span><span style="color: #007700">) AS </span><span style="color: #0000BB">ip FROM </span><span style="color: #007700">{</span><span style="color: #0000BB">flood</span><span style="color: #007700">} </span><span style="color: #0000BB">WHERE event</span><span style="color: #007700">=</span><span style="color: #DD0000">'failed_login_attempt_user' </span><span style="color: #0000BB">group by identifier</span><span style="color: #007700">; Array ( ) </span><span style="color: #0000BB">in _flood_unblock_get_entries</span><span style="color: #007700">() (</span><span style="color: #0000BB">line 225 of </span><span style="color: #007700">/</span><span style="color: #0000BB">www</span><span style="color: #007700">/</span><span style="color: #0000BB">sites</span><span style="color: #007700">/</span><span style="color: #0000BB">all</span><span style="color: #007700">/</span><span style="color: #0000BB">modules</span><span style="color: #007700">/</span><span style="color: #0000BB">flood_unblock</span><span style="color: #007700">/</span><span style="color: #0000BB">flood_unblock</span><span style="color: #007700">.</span><span style="color: #0000BB">module</span><span style="color: #007700">).<br></span><span style="color: #0000BB">?&gt;</span></span></pre></div> <p>This is caused because there's no SUBSTRING_INDEX() function in PostgreSQL. On the other hand, the PostgreSQL equivalent function SPLIT_PART() won't work in MySQL. After taking a look at the query I can see that the problematic function is used only to explode the value of the <code>identifier</code> column in ordert to get user's ID and IP, which is very easy to do in PHP (and maybe it's a bit faster?).</p> <p>The attached patch solves the issue for me, I hope it's useful for other PostgreSQL users.</p> >>> [!note] Pre-migration files - [flood\_unblock-postgresql-incompatibility-2346459-D7.patch](https://www.drupal.org/files/issues/flood_unblock-postgresql-incompatibility-2346459-D7.patch) >>>