PHP multi-process Write file

Test A

$begin= Time(); for($i= 0;$i<10000;$i++) {        $fp=fopen("tmp", ' r+ '); fseek($fp, 0,seek_end); fwrite($fp,str_repeat($argv[1],1024*32].Php_eol); fclose($fp);}$end= Time();Echo"Time use:". ($end-$begin).Php_eol;

PHP write.php b

PHP write.php A

WC-L tmp

10450 tmp

Test results:

Does not match the expected 2W line

Error Analysis:

Seek navigates to the end of the file, possibly because the other process has already written to the file, overwriting the current process

Test Two

$begin= Time(); for($i= 0;$i<10000;$i++) {        $fp=fopen("tmp", ' A + ');        fwrite($fp,str_repeat($argv[1],1024*32].Php_eol); fclose($fp);}$end= Time();Echo"Time use:". ($end-$begin).Php_eol;

PHP write.php b

PHP write.php A

WC-L tmp

20000 tmp

Test results:

Matches the expected 2W line, but checks the file contents

Check the script to check whether a row contains both A and b

<?PHP$fp=fopen("tmp", ' r+ '); while(!feof($fp)) {        $line=fgets($fp, 1024*1024); if(strstr($line, ' a ') &&strstr($line, ' B ')) {                Echo' Not pass '.Php_eol;  for($i= 0;$i<strlen($line);$i++){                        Echo Ord($line[$i]).Php_eol; }                 die; }}Echo' Pass '.Php_eol;

PHP check.php >ts

TS Content

Not pass9797...989810

Error Analysis:

PHP's fwrite is buffer, the content of writing a row is larger than the length of buffer, process A and process B are calling write to the same line in turn, resulting in this result

Test Three

Sequential Write

$begin= Time();$fp=fopen("tmp", ' w+ '); for($i= 0;$i<200000;$i++) {        fwrite($fp,str_repeat($argv[1],1024*32].Php_eol);}fclose($fp);$end= Time();Echo"Time use:". ($end-$begin).Php_eol;

PHP write.php A

Time Use:13

$begin= Time(); for($i= 0;$i<200000;$i++) {        $fp=fopen("tmp", ' A + '); fwrite($fp,str_repeat($argv[1],1024*32].Php_eol); fclose($fp);}$end= Time();Echo"Time use:". ($end-$begin).Php_eol;

PHP write.php A

Time Use:16

PHP multi-process Write file