Buffer writes not working as expected

[eduardosoliv]

Memcached::OPT_BUFFER_WRITES
Enables or disables buffered I/O. Enabling buffered I/O causes storage commands to "buffer" instead of being sent. Any action that retrieves data causes this buffer to be sent to the remote connection. Quitting the connection or closing down the connection will also cause the buffered data to be pushed to the remote connection.

Type: boolean, default: FALSE.

@ http://php.net/manual/en/memcached.constants.php

$ php -a
Interactive shell

php > $m = new \Memcached(); $m->addServer('....', 11211);
php > $m->set('test1', 10);
php > var_dump($m->get('test1'));
int(10)
php > $m->setOption(\Memcached::OPT_BUFFER_WRITES, true);
php > $m->set('test2', 20);
php > var_dump($m->get('test2'));
bool(false)
php > var_dump($m->getResultMessage());
string(9) "NOT FOUND"

I don't understand why there isn't a method like flush buffers, is already implemented at libmemcached:

http://docs.libmemcached.org/memcached_flush_buffers.html

[eduardosoliv]

Ping

[mkoppanen]

I will look at implementing this today.

[eduardosoliv]

Great

[mkoppanen]

The following seems to be working for me:

$m = new Memcached();
$m->addServer('127.0.0.1', 11211);
$m->setOption(Memcached::OPT_NO_BLOCK, 1);
$m->setOption(Memcached::OPT_BUFFER_WRITES, 1);

The documentation for libmemcached says that the writes will be flushed on get operation automatically. This doesn't seem to work without OPT_NO_BLOCK set to 1.

[eduardosoliv]

That works:

php > $m = new Memcached();
php > $m->addServer('127.0.0.1', 11211);
php > $m->setOption(Memcached::OPT_NO_BLOCK, true);
php > $m->setOption(Memcached::OPT_BUFFER_WRITES, true);
php > $m->set('test2', 20);
php > var_dump($m->get('test2'));
int(20)

I didn't know is not present at documentation

Memcached::OPT_BUFFER_WRITES
Enables or disables buffered I/O. Enabling buffered I/O causes storage commands to "buffer" instead of being sent. Any action that retrieves data causes this buffer to be sent to the remote connection. Quitting the connection or closing down the connection will also cause the buffered data to be pushed to the remote connection.
Type: boolean, default: FALSE.
http://php.net/manual/en/memcached.constants.php

Neither here:
http://docs.libmemcached.org/memcached_behavior.html?highlight=buffer#MEMCACHED_BEHAVIOR_BUFFER_REQUESTS

But memcached lib have a flush buffers:
http://docs.libmemcached.org/memcached_flush_buffers.html

I think php-memcached should have too, don't you think?

[mkoppanen]

I tested memcached_flush_buffers without NO_BLOCK set on and it doesn't seem to be working. I'll add flush buffers anyhow, as it probably works with NO_BLOCK

[eduardosoliv]

I can't find anything on libmemcached documentation that point why don't work without NO_BLOCK (or that is expected), do you think is better to fill a bug report?

[mkoppanen]

I'll try to create a reproducible test case in C and see if the issue persists. I've discovered other issues today as well so I can do the upstream report.

[sodabrew]

It's been a few years, can this issue be closed now? Is it resolved or wont-fix or still a problem?

Resolved, fixed, a new function $mc->flushBuffers() was added.