From c82829942c7e92c9286f76b3020246bab676098c Mon Sep 17 00:00:00 2001
From: Jakub Vrana <jakub@vrana.cz>
Date: Fri, 29 Jul 2011 17:08:06 +0200
Subject: [PATCH] Fast number of rows with big tables in PostgreSQL (thanks to
 juzna)

---
 adminer/drivers/mssql.inc.php  |  4 ++++
 adminer/drivers/mysql.inc.php  |  9 +++++++++
 adminer/drivers/oracle.inc.php |  4 ++++
 adminer/drivers/pgsql.inc.php  | 12 ++++++++++++
 adminer/drivers/sqlite.inc.php |  4 ++++
 adminer/select.inc.php         |  4 ++--
 changes.txt                    |  1 +
 7 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/adminer/drivers/mssql.inc.php b/adminer/drivers/mssql.inc.php
index 84b085340..9fa19c6f9 100644
--- a/adminer/drivers/mssql.inc.php
+++ b/adminer/drivers/mssql.inc.php
@@ -490,6 +490,10 @@ function explain($connection, $query) {
 		return $return;
 	}
 	
+	function found_rows($table_status, $where) {
+		return false;
+	}
+	
 	function foreign_keys($table) {
 		$return = array();
 		foreach (get_rows("EXEC sp_fkeys @fktable_name = " . q($table)) as $row) {
diff --git a/adminer/drivers/mysql.inc.php b/adminer/drivers/mysql.inc.php
index 29575ccb5..9932a7cb4 100644
--- a/adminer/drivers/mysql.inc.php
+++ b/adminer/drivers/mysql.inc.php
@@ -822,6 +822,15 @@ function explain($connection, $query) {
 		return $connection->query("EXPLAIN $query");
 	}
 	
+	/** Get approximate number of rows
+	* @param array
+	* @param array
+	* @return int or null if approximate number can't be retrieved
+	*/
+	function found_rows($table_status, $where) {
+		return ($where || $table_status["Engine"] != "InnoDB" ? null : $table_status["Rows"]);
+	}
+	
 	/** Get user defined types
 	* @return array
 	*/
diff --git a/adminer/drivers/oracle.inc.php b/adminer/drivers/oracle.inc.php
index 878d5e3c9..afe60ccc9 100644
--- a/adminer/drivers/oracle.inc.php
+++ b/adminer/drivers/oracle.inc.php
@@ -275,6 +275,10 @@ function explain($connection, $query) {
 		return $connection->query("SELECT * FROM plan_table");
 	}
 	
+	function found_rows($table_status, $where) {
+		return false;
+	}
+	
 	function alter_table($table, $name, $fields, $foreign, $comment, $engine, $collation, $auto_increment, $partitioning) {
 		$alter = $drop = array();
 		foreach ($fields as $field) {
diff --git a/adminer/drivers/pgsql.inc.php b/adminer/drivers/pgsql.inc.php
index c36fbb67d..bab11b836 100644
--- a/adminer/drivers/pgsql.inc.php
+++ b/adminer/drivers/pgsql.inc.php
@@ -511,6 +511,18 @@ function explain($connection, $query) {
 		return $connection->query("EXPLAIN $query");
 	}
 	
+	function found_rows($table_status, $where) {
+		global $connection;
+		if (ereg(
+			" rows=([0-9]+)",
+			$connection->result("EXPLAIN SELECT * FROM " . idf_escape($table_status["Name"]) . ($where ? " WHERE " . implode(" AND ", $where) : "")),
+			$regs
+		)) {
+			return $regs[1];
+		}
+		return false;
+	}
+	
 	function types() {
 		return get_vals("SELECT typname
 FROM pg_type
diff --git a/adminer/drivers/sqlite.inc.php b/adminer/drivers/sqlite.inc.php
index c7213e484..053f02f80 100644
--- a/adminer/drivers/sqlite.inc.php
+++ b/adminer/drivers/sqlite.inc.php
@@ -503,6 +503,10 @@ function explain($connection, $query) {
 		return $connection->query("EXPLAIN $query");
 	}
 	
+	function found_rows($table_status, $where) {
+		return false;
+	}
+	
 	function types() {
 		return array();
 	}
diff --git a/adminer/select.inc.php b/adminer/select.inc.php
index 56f45dd33..81bf6ffef 100644
--- a/adminer/select.inc.php
+++ b/adminer/select.inc.php
@@ -373,8 +373,8 @@
 		if ($rows || $page) {
 			$exact_count = true;
 			if ($_GET["page"] != "last" && +$limit && count($group) >= count($select) && ($found_rows >= $limit || $page)) {
-				$found_rows = $table_status["Rows"];
-				if (!isset($found_rows) || $where || ($table_status["Engine"] == "InnoDB" && $found_rows < max(1e4, 2 * ($page + 1) * $limit))) {
+				$found_rows = found_rows($table_status, $where);
+				if ($found_rows < max(1e4, 2 * ($page + 1) * $limit)) {
 					// slow with big tables
 					ob_flush(); //! doesn't work with AJAX
 					flush();
diff --git a/changes.txt b/changes.txt
index 9209e3dd0..c2a4bdbce 100644
--- a/changes.txt
+++ b/changes.txt
@@ -1,5 +1,6 @@
 Adminer 3.3.2-dev:
 Don't scroll with AJAX select order and alter move column
+Fast number of rows with big tables (PostgreSQL)
 
 Adminer 3.3.1 (released 2011-07-27):
 Fix XSS introduced in Adminer 3.2.0