(PHP 4 >= 4.2.0, PHP 5, PHP 7)
pg_free_result — 释放查询结果占用的内存
$result
) : bool
pg_free_result() 仅在当你担心脚本执行时占用了过多内存时调用。脚本执行完毕后所有的查询结果占用的内存都会被自动释放。不过如果你确认在脚本中不会再用到查询结果了，你可以用 result 作为参数调用 pg_free_result() 来释放有关的内存。成功时返回 TRUE， 或者在失败时返回 FALSE。
Note:
本函数以前的名字为 pg_freeresult()。
参见 pg_query()。
resultPostgreSQL query result resource, returned by pg_query(), pg_query_params() or pg_execute() (among others).
成功时返回 TRUE， 或者在失败时返回 FALSE。
Example #1 pg_free_result() example
<?php
$db = pg_connect("dbname=users user=me") || die();
$res = pg_query($db, "SELECT 1 UNION ALL SELECT 2");
$val = pg_fetch_result($res, 1, 0);
echo "First field in the second row is: ", $val, "\n";
pg_free_result($res);
?>
以上例程会输出：
First field in the second row is: 2
You do NOT need to call pg_free_result() on every result resource you create.
When result resources go out of scope, they are garbage collected just like everything else.
Unless you're hoarding your results somewhere, you can basically ignore this function.
Here's a little test you can run to confirm this: http://pastebin.com/ghw1PHuE