initial attempt to remove mysql-related stuff from tt-rss

10 files changed, 100 insertions, 315 deletions

diff --git a/classes/Article.php b/classes/Article.php
index efb5e4e89..bfff11e6b 100644
--- a/classes/Article.php
+++ b/classes/Article.php
@@ -85,15 +85,13 @@ class Article extends Handler_Protected {
 					content = ?, content_hash = ? WHERE id = ?");
 				$sth->execute([$content, $content_hash, $ref_id]);
 
-				if (Config::get(Config::DB_TYPE) == "pgsql") {
-					$sth = $pdo->prepare("UPDATE ttrss_entries
-					SET tsvector_combined = to_tsvector( :ts_content)
-					WHERE id = :id");
-					$params = [
-						":ts_content" => mb_substr(\Soundasleep\Html2Text::convert($content), 0, 900000),
-						":id" => $ref_id];
-					$sth->execute($params);
-				}
+				$sth = $pdo->prepare("UPDATE ttrss_entries
+				SET tsvector_combined = to_tsvector( :ts_content)
+				WHERE id = :id");
+				$params = [
+					":ts_content" => mb_substr(\Soundasleep\Html2Text::convert($content), 0, 900000),
+					":id" => $ref_id];
+				$sth->execute($params);
 
 				$sth = $pdo->prepare("UPDATE ttrss_user_entries SET published = true,
 						last_published = NOW() WHERE
@@ -130,15 +128,15 @@ class Article extends Handler_Protected {
 
 			if ($row = $sth->fetch()) {
 				$ref_id = $row["id"];
-				if (Config::get(Config::DB_TYPE) == "pgsql"){
-					$sth = $pdo->prepare("UPDATE ttrss_entries
-					SET tsvector_combined = to_tsvector( :ts_content)
-					WHERE id = :id");
-					$params = [
-						":ts_content" => mb_substr(\Soundasleep\Html2Text::convert($content), 0, 900000),
-						":id" => $ref_id];
-					$sth->execute($params);
-				}
+
+				$sth = $pdo->prepare("UPDATE ttrss_entries
+				SET tsvector_combined = to_tsvector( :ts_content)
+				WHERE id = :id");
+				$params = [
+					":ts_content" => mb_substr(\Soundasleep\Html2Text::convert($content), 0, 900000),
+					":id" => $ref_id];
+				$sth->execute($params);
+
 				$sth = $pdo->prepare("INSERT INTO ttrss_user_entries
 					(ref_id, uuid, feed_id, orig_feed_id, owner_uid, published, tag_cache, label_cache,
 						last_read, note, unread, last_published)
@@ -465,16 +463,9 @@ class Article extends Handler_Protected {
 
 	static function _purge_orphans(): void {
 
-        // purge orphaned posts in main content table
-
-        if (Config::get(Config::DB_TYPE) == "mysql")
-            $limit_qpart = "LIMIT 5000";
-        else
-            $limit_qpart = "";
-
         $pdo = Db::pdo();
         $res = $pdo->query("DELETE FROM ttrss_entries WHERE
-			NOT EXISTS (SELECT ref_id FROM ttrss_user_entries WHERE ref_id = id) $limit_qpart");
+			NOT EXISTS (SELECT ref_id FROM ttrss_user_entries WHERE ref_id = id)");
 
         if (Debug::enabled()) {
             $rows = $res->rowCount();
diff --git a/classes/Config.php b/classes/Config.php
index 5098bfe68..f8f9aaa18 100644
--- a/classes/Config.php
+++ b/classes/Config.php
@@ -24,7 +24,7 @@ class Config {
 	 *
 	*/
 
-	/** database type: pgsql or mysql */
+	/** database type: pgsql */
 	const DB_TYPE = "DB_TYPE";
 
 	/** database server hostname */
@@ -42,10 +42,6 @@ class Config {
 	/** database server port */
 	const DB_PORT = "DB_PORT";
 
-	/** connection charset for MySQL. if you have a legacy database and/or experience
-	 * garbage unicode characters with this option, try setting it to a blank string. */
-	const MYSQL_CHARSET = "MYSQL_CHARSET";
-
 	/** this is a fallback falue for the CLI SAPI, it should be set to a fully-qualified tt-rss URL */
 	const SELF_URL_PATH = "SELF_URL_PATH";
 
@@ -204,7 +200,6 @@ class Config {
 		Config::DB_NAME => [ "", 											Config::T_STRING ],
 		Config::DB_PASS => [ "", 											Config::T_STRING ],
 		Config::DB_PORT => [ "5432",										Config::T_STRING ],
-		Config::MYSQL_CHARSET => [ "UTF8",								Config::T_STRING ],
 		Config::SELF_URL_PATH => [ "https://example.com/tt-rss", Config::T_STRING ],
 		Config::SINGLE_USER_MODE => [ "",								Config::T_BOOL ],
 		Config::SIMPLE_UPDATE_MODE => [ "",								Config::T_BOOL ],
@@ -481,25 +476,6 @@ class Config {
 	}
 	/* sanity check stuff */
 
-	/** checks for mysql tables not using InnoDB (tt-rss is incompatible with MyISAM)
-	 * @return array<int, array<string, string>> A list of entries identifying tt-rss tables with bad config
-	 */
-	private static function check_mysql_tables() {
-		$pdo = Db::pdo();
-
-		$sth = $pdo->prepare("SELECT engine, table_name FROM information_schema.tables WHERE
-				table_schema = ? AND table_name LIKE 'ttrss_%' AND engine != 'InnoDB'");
-		$sth->execute([self::get(Config::DB_NAME)]);
-
-		$bad_tables = [];
-
-		while ($line = $sth->fetch()) {
-			array_push($bad_tables, $line);
-		}
-
-		return $bad_tables;
-	}
-
 	static function sanity_check(): void {
 
 		/*
@@ -604,29 +580,6 @@ class Config {
 			}
 		}
 
-		if (self::get(Config::DB_TYPE) == "mysql") {
-			$bad_tables = self::check_mysql_tables();
-
-			if (count($bad_tables) > 0) {
-				$bad_tables_fmt = [];
-
-				foreach ($bad_tables as $bt) {
-					array_push($bad_tables_fmt, sprintf("%s (%s)", $bt['table_name'], $bt['engine']));
-				}
-
-				$msg = "<p>The following tables use an unsupported MySQL engine: <b>" .
-					implode(", ", $bad_tables_fmt) . "</b>.</p>";
-
-				$msg .= "<p>The only supported engine on MySQL is InnoDB. MyISAM lacks functionality to run
-					tt-rss.
-					Please backup your data (via OPML) and re-import the schema before continuing.</p>
-					<p><b>WARNING: importing the schema would mean LOSS OF ALL YOUR DATA.</b></p>";
-
-
-				array_push($errors, $msg);
-			}
-		}
-
 		if (count($errors) > 0 && php_sapi_name() != "cli") {
 			http_response_code(503); ?>
 
diff --git a/classes/Db.php b/classes/Db.php
index 8e0e7047b..92bbec8b4 100644
--- a/classes/Db.php
+++ b/classes/Db.php
@@ -9,9 +9,6 @@ class Db {
 		ORM::configure('username', Config::get(Config::DB_USER));
 		ORM::configure('password', Config::get(Config::DB_PASS));
 		ORM::configure('return_result_sets', true);
-		if (Config::get(Config::DB_TYPE) == "mysql" && Config::get(Config::MYSQL_CHARSET)) {
-			ORM::configure('driver_options', array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES ' . Config::get(Config::MYSQL_CHARSET)));
-		}
 	}
 
 	/**
@@ -29,13 +26,8 @@ class Db {
 	public static function get_dsn(): string {
 		$db_port = Config::get(Config::DB_PORT) ? ';port=' . Config::get(Config::DB_PORT) : '';
 		$db_host = Config::get(Config::DB_HOST) ? ';host=' . Config::get(Config::DB_HOST) : '';
-		if (Config::get(Config::DB_TYPE) == "mysql" && Config::get(Config::MYSQL_CHARSET)) {
-			$db_charset = ';charset=' . Config::get(Config::MYSQL_CHARSET);
-		} else {
-			$db_charset = '';
-		}
 
-		return Config::get(Config::DB_TYPE) . ':dbname=' . Config::get(Config::DB_NAME) . $db_host . $db_port . $db_charset;
+		return Config::get(Config::DB_TYPE) . ':dbname=' . Config::get(Config::DB_NAME) . $db_host . $db_port;
 	}
 
 	// this really shouldn't be used unless a separate PDO connection is needed
@@ -53,20 +45,10 @@ class Db {
 
 		$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 
-		if (Config::get(Config::DB_TYPE) == "pgsql") {
-
-			$pdo->query("set client_encoding = 'UTF-8'");
-			$pdo->query("set datestyle = 'ISO, european'");
-			$pdo->query("set TIME ZONE 0");
-			$pdo->query("set cpu_tuple_cost = 0.5");
-
-		} else if (Config::get(Config::DB_TYPE) == "mysql") {
-			$pdo->query("SET time_zone = '+0:0'");
-
-			if (Config::get(Config::MYSQL_CHARSET)) {
-				$pdo->query("SET NAMES " . Config::get(Config::MYSQL_CHARSET));
-			}
-		}
+		$pdo->query("set client_encoding = 'UTF-8'");
+		$pdo->query("set datestyle = 'ISO, european'");
+		$pdo->query("set TIME ZONE 0");
+		$pdo->query("set cpu_tuple_cost = 0.5");
 
 		return $pdo;
 	}
@@ -90,15 +72,12 @@ class Db {
 	}
 
 	public static function sql_random_function(): string {
-		if (Config::get(Config::DB_TYPE) == "mysql") {
-			return "RAND()";
-		}
 		return "RANDOM()";
 	}
 
 	/**
 	 * Helper to build a query part comparing a field against a past datetime (determined by "$now - $some_interval")
-	 * 
+	 *
 	 * The example below could be read as "last_digest_sent is older than 1 day ago".
 	 * ```php
 	 * Db::past_comparison_qpart('last_digest_sent', '<', 1, 'day');
@@ -106,7 +85,6 @@ class Db {
 	 *
 	 * @todo validate value of $unit and fail if invalid (or massage if practical)?
 	 * @link https://www.postgresql.org/docs/current/datatype-datetime.html#DATATYPE-INTERVAL-INPUT
-	 * @link https://dev.mysql.com/doc/refman/9.2/en/expressions.html#temporal-intervals
 	 * @param string $field the table field being checked
 	 * @param '<'|'>'|'<='|'>='|'=' $operator the comparison operator
 	 * @param positive-int $quantity the amount of $unit
@@ -114,8 +92,6 @@ class Db {
 	 * @return string the query part string
 	 */
 	static function past_comparison_qpart(string $field, string $operator, int $quantity, string $unit): string {
-		if (Config::get(Config::DB_TYPE) == 'pgsql')
-			return "$field $operator NOW() - INTERVAL '$quantity $unit' ";
-		return "$field $operator DATE_SUB(NOW(), INTERVAL $quantity $unit) ";
+		return "$field $operator NOW() - INTERVAL '$quantity $unit' ";
 	}
 }
diff --git a/classes/Db_Migrations.php b/classes/Db_Migrations.php
index 7dcfc24b1..62619b377 100644
--- a/classes/Db_Migrations.php
+++ b/classes/Db_Migrations.php
@@ -88,9 +88,7 @@ class Db_Migrations {
 			$lines = $this->get_lines($version);
 
 			if (count($lines) > 0) {
-				// mysql doesn't support transactions for DDL statements
-				if (Config::get(Config::DB_TYPE) != "mysql")
-					$this->pdo->beginTransaction();
+				$this->pdo->beginTransaction();
 
 				foreach ($lines as $line) {
 					Debug::log($line, Debug::LOG_EXTENDED);
@@ -107,8 +105,7 @@ class Db_Migrations {
 				else
 					$this->set_version($version);
 
-				if (Config::get(Config::DB_TYPE) != "mysql")
-					$this->pdo->commit();
+				$this->pdo->commit();
 
 				Debug::log("Migration finished, current version: " . $this->get_version(), Debug::LOG_VERBOSE);
 
diff --git a/classes/FeedItem_Common.php b/classes/FeedItem_Common.php
index 5ec958699..241640cc4 100644
--- a/classes/FeedItem_Common.php
+++ b/classes/FeedItem_Common.php
@@ -91,6 +91,7 @@ abstract class FeedItem_Common extends FeedItem {
 
 		$enclosures = $this->xpath->query("media:content", $this->elem);
 
+		/** @var DOMElement $enclosure */
 		foreach ($enclosures as $enclosure) {
 			$enc = new FeedEnclosure();
 			$enc->type = clean($enclosure->getAttribute('type'));
@@ -143,6 +144,7 @@ abstract class FeedItem_Common extends FeedItem {
 
 		$enclosures = $this->xpath->query("media:thumbnail", $this->elem);
 
+		/** @var DOMElement $enclosure */
 		foreach ($enclosures as $enclosure) {
 			$enc = new FeedEnclosure();
 			$enc->type = 'image/generic';
@@ -193,10 +195,6 @@ abstract class FeedItem_Common extends FeedItem {
 
 			$cat = preg_replace('/[,\'\"]/', "", $cat);
 
-			if (Config::get(Config::DB_TYPE) == "mysql") {
-				$cat = preg_replace('/[\x{10000}-\x{10FFFF}]/u', "\xEF\xBF\xBD", $cat);
-			}
-
 			if (mb_strlen($cat) > 250)
 				$cat = mb_substr($cat, 0, 250);
 
diff --git a/classes/Feeds.php b/classes/Feeds.php
index 7d818598d..bea3bb0f4 100644
--- a/classes/Feeds.php
+++ b/classes/Feeds.php
@@ -217,17 +217,6 @@ class Feeds extends Handler_Protected {
 
 				$id = $line["id"];
 
-				// frontend doesn't expect pdo returning booleans as strings on mysql
-				if (Config::get(Config::DB_TYPE) == "mysql") {
-					foreach (["unread", "marked", "published"] as $k) {
-						if (is_integer($line[$k])) {
-							$line[$k] = $line[$k] === 1;
-						} else {
-							$line[$k] = $line[$k] === "1";
-						}
-					}
-				}
-
 				// normalize archived feed
 				if ($line['feed_id'] === null) {
 					$line['feed_id'] = Feeds::FEED_ARCHIVED;
@@ -582,7 +571,7 @@ class Feeds extends Handler_Protected {
 
 	function search(): void {
 		print json_encode([
-			"show_language" => Config::get(Config::DB_TYPE) == "pgsql",
+			"show_language" => true,
 			"show_syntax_help" => count(PluginHost::getInstance()->get_hooks(PluginHost::HOOK_SEARCH)) == 0,
 			"all_languages" => Pref_Feeds::get_ts_languages(),
 			"default_language" => Prefs::get(Prefs::DEFAULT_SEARCH_LANGUAGE, $_SESSION['uid'], $_SESSION['profile'] ?? null)
@@ -1407,18 +1396,16 @@ class Feeds extends Handler_Protected {
 				list($search_query_part, $search_words) = self::_search_to_sql($search, $search_language, $owner_uid, $profile);
 			}
 
-			if (Config::get(Config::DB_TYPE) == "pgsql") {
-				$test_sth = $pdo->prepare("select $search_query_part
-					FROM ttrss_entries, ttrss_user_entries WHERE id = ref_id limit 1");
+			$test_sth = $pdo->prepare("select $search_query_part
+				FROM ttrss_entries, ttrss_user_entries WHERE id = ref_id limit 1");
 
-				try {
-					$test_sth->execute();
-				} catch (PDOException $e) {
-					// looks like tsquery syntax is invalid
-					$search_query_part = "false";
+			try {
+				$test_sth->execute();
+			} catch (PDOException $e) {
+				// looks like tsquery syntax is invalid
+				$search_query_part = "false";
 
-					$query_error_override = T_sprintf("Incorrect search syntax: %s.", implode(" ", $search_words));
-				}
+				$query_error_override = T_sprintf("Incorrect search syntax: %s.", implode(" ", $search_words));
 			}
 
 			$search_query_part .= " AND ";
@@ -1635,11 +1622,7 @@ class Feeds extends Handler_Protected {
 
 		$first_id = 0;
 
-		if (Config::get(Config::DB_TYPE) == "pgsql") {
-			$yyiw_qpart = "to_char(date_entered, 'IYYY-IW') AS yyiw";
-		} else {
-			$yyiw_qpart = "date_format(date_entered, '%Y-%u') AS yyiw";
-		}
+		$yyiw_qpart = "to_char(date_entered, 'IYYY-IW') AS yyiw";
 
 		if (is_numeric($feed)) {
 			// proper override_order applied above
@@ -1679,12 +1662,8 @@ class Feeds extends Handler_Protected {
 
 			$sanity_interval_qpart = Db::past_comparison_qpart('date_entered', '>=', 1, 'hour') . ' AND ';
 
-			if (Config::get(Config::DB_TYPE) == "pgsql") {
-				$distinct_columns = str_replace("desc", "", strtolower($order_by));
-				$distinct_qpart = "DISTINCT ON (id, $distinct_columns)";
-			} else {
-				$distinct_qpart = "DISTINCT"; //fallback
-			}
+			$distinct_columns = str_replace("desc", "", strtolower($order_by));
+			$distinct_qpart = "DISTINCT ON (id, $distinct_columns)";
 
 			// except for Labels category
 			if (Prefs::get(Prefs::HEADLINES_NO_DISTINCT, $owner_uid, $profile)
@@ -1785,12 +1764,8 @@ class Feeds extends Handler_Protected {
 			if (Prefs::get(Prefs::HEADLINES_NO_DISTINCT, $owner_uid, $profile)) {
 				$distinct_qpart = "";
 			} else {
-				if (Config::get(Config::DB_TYPE) == "pgsql") {
-					$distinct_columns = str_replace("desc", "", strtolower($order_by));
-					$distinct_qpart = "DISTINCT ON (id, $distinct_columns)";
-				} else {
-					$distinct_qpart = "DISTINCT"; //fallback
-				}
+				$distinct_columns = str_replace("desc", "", strtolower($order_by));
+				$distinct_qpart = "DISTINCT ON (id, $distinct_columns)";
 			}
 
 			$query = "SELECT $distinct_qpart
@@ -2099,27 +2074,14 @@ class Feeds extends Handler_Protected {
 			else
 				$query_limit = "";
 
-			if (Config::get(Config::DB_TYPE) == "pgsql") {
-				$sth = $pdo->prepare("DELETE FROM ttrss_user_entries
-					USING ttrss_entries
-					WHERE ttrss_entries.id = ref_id AND
-					marked = false AND
-					feed_id = ? AND
-					$query_limit
-					ttrss_entries.date_updated < NOW() - INTERVAL '$purge_interval days'");
-				$sth->execute([$feed_id]);
-
-			} else {
-				$sth  = $pdo->prepare("DELETE FROM ttrss_user_entries
-					USING ttrss_user_entries, ttrss_entries
-					WHERE ttrss_entries.id = ref_id AND
-					marked = false AND
-					feed_id = ? AND
-					$query_limit
-					ttrss_entries.date_updated < DATE_SUB(NOW(), INTERVAL $purge_interval DAY)");
-				$sth->execute([$feed_id]);
-
-			}
+			$sth = $pdo->prepare("DELETE FROM ttrss_user_entries
+				USING ttrss_entries
+				WHERE ttrss_entries.id = ref_id AND
+				marked = false AND
+				feed_id = ? AND
+				$query_limit
+				ttrss_entries.date_updated < NOW() - INTERVAL '$purge_interval days'");
+			$sth->execute([$feed_id]);
 
 			$rows_deleted = $sth->rowCount();
 
@@ -2286,16 +2248,12 @@ class Feeds extends Handler_Protected {
 
 						$k = mb_strtolower($k);
 
-						if (Config::get(Config::DB_TYPE) == "pgsql") {
-							// A hacky way for phrases (e.g. "hello world") to get through PDO quoting.
-							// Term '"foo bar baz"' becomes '(foo <-> bar <-> baz)' ("<->" meaning "immediately followed by").
-							if (preg_match('/\s+/', $k))
-								$k = '(' . preg_replace('/\s+/', ' <-> ', $k) . ')';
+						// A hacky way for phrases (e.g. "hello world") to get through PDO quoting.
+						// Term '"foo bar baz"' becomes '(foo <-> bar <-> baz)' ("<->" meaning "immediately followed by").
+						if (preg_match('/\s+/', $k))
+							$k = '(' . preg_replace('/\s+/', ' <-> ', $k) . ')';
 
-							array_push($search_query_leftover, $not ? "!$k" : $k);
-						} else {
-							array_push($search_query_leftover, $not ? "-$k" : $k);
-						}
+						array_push($search_query_leftover, $not ? "!$k" : $k);
 
 						if (!$not) array_push($search_words, $k);
 					}
@@ -2304,26 +2262,18 @@ class Feeds extends Handler_Protected {
 
 		if (count($search_query_leftover) > 0) {
 
-			if (Config::get(Config::DB_TYPE) == "pgsql") {
-
-				// if there's no joiners consider this a "simple" search and
-				// concatenate everything with &, otherwise don't try to mess with tsquery syntax
-				if (preg_match("/[&|]/", implode(" " , $search_query_leftover))) {
-					$tsquery = $pdo->quote(implode(" ", $search_query_leftover));
-				} else {
-					$tsquery = $pdo->quote(implode(" & ", $search_query_leftover));
-				}
-
-				$search_language = $pdo->quote(mb_strtolower($search_language ?: Prefs::get(Prefs::DEFAULT_SEARCH_LANGUAGE, $owner_uid, $profile)));
-
-				array_push($query_keywords,
-					"(tsvector_combined @@ to_tsquery($search_language, $tsquery))");
+			// if there's no joiners consider this a "simple" search and
+			// concatenate everything with &, otherwise don't try to mess with tsquery syntax
+			if (preg_match("/[&|]/", implode(" " , $search_query_leftover))) {
+				$tsquery = $pdo->quote(implode(" ", $search_query_leftover));
 			} else {
-				$ft_query = $pdo->quote(implode(" ", $search_query_leftover));
-
-				array_push($query_keywords,
-					"MATCH (ttrss_entries.title, ttrss_entries.content) AGAINST ($ft_query IN BOOLEAN MODE)");
+				$tsquery = $pdo->quote(implode(" & ", $search_query_leftover));
 			}
+
+			$search_language = $pdo->quote(mb_strtolower($search_language ?: Prefs::get(Prefs::DEFAULT_SEARCH_LANGUAGE, $owner_uid, $profile)));
+
+			array_push($query_keywords,
+				"(tsvector_combined @@ to_tsquery($search_language, $tsquery))");
 		}
 
 		if (count($query_keywords) > 0)
diff --git a/classes/Pref_Feeds.php b/classes/Pref_Feeds.php
index bc059b99f..75ae053bd 100644
--- a/classes/Pref_Feeds.php
+++ b/classes/Pref_Feeds.php
@@ -15,12 +15,8 @@ class Pref_Feeds extends Handler_Protected {
 	 * @return array<int, string>
 	 */
 	public static function get_ts_languages(): array {
-		if (Config::get(Config::DB_TYPE) == 'pgsql') {
-			return array_map('ucfirst',
-				array_column(ORM::for_table('pg_ts_config')->select('cfgname')->find_array(), 'cfgname'));
-		}
-
-		return [];
+		return array_map('ucfirst',
+			array_column(ORM::for_table('pg_ts_config')->select('cfgname')->find_array(), 'cfgname'));
 	}
 
 	function renameCat(): void {
@@ -597,7 +593,7 @@ class Pref_Feeds extends Handler_Protected {
 					"access_level" => $user->access_level
 				],
 				"lang" => [
-					"enabled" => Config::get(Config::DB_TYPE) == "pgsql",
+					"enabled" => true,
 					"default" => Prefs::get(Prefs::DEFAULT_SEARCH_LANGUAGE, $_SESSION['uid'], $profile),
 					"all" => $this::get_ts_languages(),
 					]
@@ -653,13 +649,11 @@ class Pref_Feeds extends Handler_Protected {
 					</fieldset>
 				<?php } ?>
 
-				<?php	if (Config::get(Config::DB_TYPE) == "pgsql") { ?>
 					<fieldset>
 						<label><?= __('Language:') ?></label>
 						<?= \Controls\select_tag("feed_language", "", $this::get_ts_languages(), ["disabled"=> 1]) ?>
 						<?= $this->_batch_toggle_checkbox("feed_language") ?>
 					</fieldset>
-				<?php } ?>
 				</section>
 
 				<hr/>
@@ -1141,12 +1135,6 @@ class Pref_Feeds extends Handler_Protected {
 
 	function inactiveFeeds(): void {
 
-		if (Config::get(Config::DB_TYPE) == "pgsql") {
-			$interval_qpart = "NOW() - INTERVAL '3 months'";
-		} else {
-			$interval_qpart = "DATE_SUB(NOW(), INTERVAL 3 MONTH)";
-		}
-
 		$inactive_feeds = ORM::for_table('ttrss_feeds')
 			->table_alias('f')
 			->select_many('f.id', 'f.title', 'f.site_url', 'f.feed_url')
@@ -1158,7 +1146,7 @@ class Pref_Feeds extends Handler_Protected {
 				"(SELECT MAX(ttrss_entries.updated)
 				FROM ttrss_entries
 				JOIN ttrss_user_entries ON ttrss_entries.id = ttrss_user_entries.ref_id
-				WHERE ttrss_user_entries.feed_id = f.id) < $interval_qpart")
+				WHERE ttrss_user_entries.feed_id = f.id) < NOW() - INTERVAL '3 months'")
 			->group_by('f.title')
 			->group_by('f.id')
 			->group_by('f.site_url')
diff --git a/classes/Pref_Prefs.php b/classes/Pref_Prefs.php
index c96c84100..6942e711c 100644
--- a/classes/Pref_Prefs.php
+++ b/classes/Pref_Prefs.php
@@ -591,10 +591,6 @@ class Pref_Prefs extends Handler_Protected {
 					continue;
 				}
 
-				if ($pref_name == Prefs::DEFAULT_SEARCH_LANGUAGE && Config::get(Config::DB_TYPE) != "pgsql") {
-					continue;
-				}
-
 				if (isset($prefs_available[$pref_name])) {
 
 					$item = $prefs_available[$pref_name];
diff --git a/classes/RPC.php b/classes/RPC.php
index 82f85fc11..bad51e4aa 100644
--- a/classes/RPC.php
+++ b/classes/RPC.php
@@ -252,33 +252,18 @@ class RPC extends Handler_Protected {
 		$default_interval = (int) Prefs::get_default(Prefs::DEFAULT_UPDATE_INTERVAL);
 
 		// Test if the feed need a update (update interval exceded).
-		if (Config::get(Config::DB_TYPE) == "pgsql") {
-			$update_limit_qpart = "AND ((
-					update_interval = 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND last_updated < NOW() - CAST((COALESCE(p.value, '$default_interval') || ' minutes') AS INTERVAL)
-				) OR (
-					update_interval > 0
-						AND last_updated < NOW() - CAST((update_interval || ' minutes') AS INTERVAL)
-				) OR (
-					update_interval >= 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND (last_updated = '1970-01-01 00:00:00' OR last_updated IS NULL)
-				))";
-		} else {
-			$update_limit_qpart = "AND ((
-					update_interval = 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND last_updated < DATE_SUB(NOW(), INTERVAL CONVERT(COALESCE(p.value, '$default_interval'), SIGNED INTEGER) MINUTE)
-				) OR (
-					update_interval > 0
-						AND last_updated < DATE_SUB(NOW(), INTERVAL update_interval MINUTE)
-				) OR (
-					update_interval >= 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND (last_updated = '1970-01-01 00:00:00' OR last_updated IS NULL)
-				))";
-		}
+		$update_limit_qpart = "AND ((
+				update_interval = 0
+					AND (p.value IS NULL OR p.value != '-1')
+					AND last_updated < NOW() - CAST((COALESCE(p.value, '$default_interval') || ' minutes') AS INTERVAL)
+			) OR (
+				update_interval > 0
+					AND last_updated < NOW() - CAST((update_interval || ' minutes') AS INTERVAL)
+			) OR (
+				update_interval >= 0
+					AND (p.value IS NULL OR p.value != '-1')
+					AND (last_updated = '1970-01-01 00:00:00' OR last_updated IS NULL)
+			))";
 
 		// Test if feed is currently being updated by another process.
 		$updstart_thresh_qpart = 'AND (last_update_started IS NULL OR '
diff --git a/classes/RSSUtils.php b/classes/RSSUtils.php
index f6a81d00f..547cc094b 100644
--- a/classes/RSSUtils.php
+++ b/classes/RSSUtils.php
@@ -35,11 +35,6 @@ class RSSUtils {
 		return sha1(implode(",", $pluginhost->get_plugin_names()) . $tmp);
 	}
 
-	// Strips utf8mb4 characters (i.e. emoji) for mysql
-	static function strip_utf8mb4(string $str): string {
-		return preg_replace('/[\x{10000}-\x{10FFFF}]/u', "\xEF\xBF\xBD", $str);
-	}
-
 	static function cleanup_feed_browser(): void {
 		$pdo = Db::pdo();
 		$pdo->query("DELETE FROM ttrss_feedbrowser_cache");
@@ -123,33 +118,18 @@ class RSSUtils {
 
 		$default_interval = (int) Prefs::get_default(Prefs::DEFAULT_UPDATE_INTERVAL);
 
-		if (Config::get(Config::DB_TYPE) == "pgsql") {
-			$update_limit_qpart = "AND ((
-					update_interval = 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND last_updated < NOW() - CAST((COALESCE(p.value, '$default_interval') || ' minutes') AS INTERVAL)
-				) OR (
-					update_interval > 0
-					AND last_updated < NOW() - CAST((update_interval || ' minutes') AS INTERVAL)
-				) OR (
-					update_interval >= 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND (last_updated = '1970-01-01 00:00:00' OR last_updated IS NULL)
-				))";
-		} else {
-			$update_limit_qpart = "AND ((
-					update_interval = 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND last_updated < DATE_SUB(NOW(), INTERVAL CONVERT(COALESCE(p.value, '$default_interval'), SIGNED INTEGER) MINUTE)
-				) OR (
-					update_interval > 0
-						AND last_updated < DATE_SUB(NOW(), INTERVAL update_interval MINUTE)
-				) OR (
-					update_interval >= 0
-						AND (p.value IS NULL OR p.value != '-1')
-						AND (last_updated = '1970-01-01 00:00:00' OR last_updated IS NULL)
-				))";
-		}
+		$update_limit_qpart = "AND ((
+				update_interval = 0
+					AND (p.value IS NULL OR p.value != '-1')
+					AND last_updated < NOW() - CAST((COALESCE(p.value, '$default_interval') || ' minutes') AS INTERVAL)
+			) OR (
+				update_interval > 0
+				AND last_updated < NOW() - CAST((update_interval || ' minutes') AS INTERVAL)
+			) OR (
+				update_interval >= 0
+					AND (p.value IS NULL OR p.value != '-1')
+					AND (last_updated = '1970-01-01 00:00:00' OR last_updated IS NULL)
+			))";
 
 		// Test if feed is currently being updated by another process.
 		// TODO: Update RPC::updaterandomfeed_real() to also use 10 minutes?
@@ -159,10 +139,7 @@ class RSSUtils {
 		$query_limit = $limit ? sprintf("LIMIT %d", $limit) : "";
 
 		// Update the least recently updated feeds first
-		$query_order = "ORDER BY last_updated";
-
-		if (Config::get(Config::DB_TYPE) == "pgsql")
-			$query_order .= " NULLS FIRST";
+		$query_order = "ORDER BY last_updated NULLS FIRST";
 
 		$query = "SELECT f.feed_url, f.last_updated
 			FROM
@@ -856,15 +833,6 @@ class RSSUtils {
 						continue;
 					}
 
-					// Yet another episode of "mysql utf8_general_ci is gimped"
-					if (Config::get(Config::DB_TYPE) == "mysql" && Config::get(Config::MYSQL_CHARSET) != "UTF8MB4") {
-						foreach ((array)$e as $prop => $val) {
-							if (is_string($val)) {
-								$e->$prop = self::strip_utf8mb4($val);
-							}
-						}
-					}
-
 					array_push($enclosures, $e);
 				}
 
@@ -935,16 +903,6 @@ class RSSUtils {
 
 				Debug::log("plugin data: {$entry_plugin_data}", Debug::LOG_VERBOSE);
 
-				// Workaround: 4-byte unicode requires utf8mb4 in MySQL. See https://tt-rss.org/forum/viewtopic.php?f=1&t=3377&p=20077#p20077
-				if (Config::get(Config::DB_TYPE) == "mysql" && Config::get(Config::MYSQL_CHARSET) != "UTF8MB4") {
-					foreach ($article as $k => $v) {
-						// i guess we'll have to take the risk of 4byte unicode labels & tags here
-						if (is_string($article[$k])) {
-							$article[$k] = self::strip_utf8mb4($v);
-						}
-					}
-				}
-
 				/* Collect article tags here so we could filter by them: */
 
 				$matched_rules = [];
@@ -1186,14 +1144,9 @@ class RSSUtils {
 
 					Debug::log("resulting RID: $entry_ref_id, IID: $entry_int_id", Debug::LOG_VERBOSE);
 
-					if (Config::get(Config::DB_TYPE) == "pgsql")
-						$tsvector_qpart = "tsvector_combined = to_tsvector(:ts_lang, :ts_content),";
-					else
-						$tsvector_qpart = "";
-
 					$sth = $pdo->prepare("UPDATE ttrss_entries
 						SET title = :title,
-							$tsvector_qpart
+							tsvector_combined = to_tsvector(:ts_lang, :ts_content),
 							content = :content,
 							content_hash = :content_hash,
 							updated = :updated,
@@ -1212,12 +1165,10 @@ class RSSUtils {
 						":plugin_data" => $entry_plugin_data,
 						":author" => "$entry_author",
 						":lang" => $entry_language,
-						":id" => $ref_id];
-
-					if (Config::get(Config::DB_TYPE) == "pgsql") {
-						$params[":ts_lang"] = $feed_language;
-						$params[":ts_content"] = mb_substr(strip_tags($entry_title) . " " . \Soundasleep\Html2Text::convert($entry_content), 0, 900000);
-					}
+						":id" => $ref_id,
+						":ts_lang" => $feed_language,
+						":ts_content" => mb_substr(strip_tags($entry_title) . " " . \Soundasleep\Html2Text::convert($entry_content), 0, 900000)
+						];
 
 					$sth->execute($params);