# Fastcgi chunked data **URL:** \ **Category:** NGINX\ **Created:** [August 19, 2011, 2:39am UTC](https://www.ruby-forum.com/t/fastcgi-chunked-data/210862 "2011-08-19T02:39:30Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\ **Post date:** [August 19, 2011, 2:39am UTC](https://www.ruby-forum.com/t/fastcgi-chunked-data/210862/1 "2011-08-19T02:39:30Z")
I have a fastcgi server connection that send chunks of data. I would like to have the chucks of data written to downstream, not buffered. I want to send chunked data from the server, but nginx buffers the data, I want to flush the data immediately. I have found the “trunk” 1.1.0 code almost works. 1\> The event happens 2\> the pipe is read 3\> something is checked??? 4\> the data is buffered, not written downstream 5\> try to write down stream, but no buffer, Why? 5\> checks upstream again 6\> starts timer again I have traced the code but I get lost at [debug] 2842#0: \*4 pipe recv chain: -2 src/event/ngx\_event\_pipe.c:272 n = p-\>upstream-\>recv\_chain(p-\>upstream, chain); ``` ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0, "pipe recv chain: %z", n); ``` AND why there is no buffer to write? [debug] 2842#0: \*4 pipe write downstream: 1 0000000000000000 2011/08/18 17:26:01 [debug] 2842#0: \*4 post event 0000000001FF1BF0 2011/08/18 17:26:01 [debug] 2842#0: \*4 post event 0000000002005400 2011/08/18 17:26:01 [debug] 2842#0: \*4 delete posted event 0000000002005400 2011/08/18 17:26:01 [debug] 2842#0: \*4 http upstream request: “/mafw/weiqi.psh?” 1 2011/08/18 17:26:01 [debug] 2842#0: \*4 http upstream dummy handler 2011/08/18 17:26:01 [debug] 2842#0: \*4 delete posted event 0000000001FF1BF0 2011/08/18 17:26:01 [debug] 2842#0: \*4 http upstream request: “/mafw/weiqi.psh?” 0 2011/08/18 17:26:01 [debug] 2842#0: \*4 http upstream process upstream 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe read upstream: 1 2011/08/18 17:26:01 [debug] 2842#0: \*4 readv: 2:4096 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe recv chain: 144 2011/08/18 17:26:01 [debug] 2842#0: \*4 readv: 2:4096 2011/08/18 17:26:01 [debug] 2842#0: \*4 readv() not ready (11: Resource temporarily unavailable) 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe recv chain: -2 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe buf free s:0 t:1 f:0 0000000001FC9750, pos 0000000001FC9750, size: 3368 file: 0, size: 0 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe buf free s:0 t:1 f:0 0000000001FC7730, pos 0000000001FC7730, size: 0 file: 0, size: 0 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe write downstream: 1 0000000000000000 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe write busy: 0 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe write: out:0000000000000000, f:0 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe read upstream: 0 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe buf free s:0 t:1 f:0 0000000001FC9750, pos 0000000001FC9750, size: 3368 file: 0, size: 0 2011/08/18 17:26:01 [debug] 2842#0: \*4 pipe buf free s:0 t:1 f:0 0000000001FC7730, pos 0000000001FC7730, size: 0 file: 0, size: 0 2011/08/18 17:26:01 [debug] 2842#0: \*4 event timer del: 20: 1313659596126 2011/08/18 17:26:01 [debug] 2842#0: \*4 event timer add: 20: 60000:1313659621126 ---
**Author:** ![Shaun\_savage](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/e9a140/32.png) [@Shaun\_savage](https://www.ruby-forum.com/u/Shaun_savage)\ **Post date:** [August 19, 2011, 6:45am UTC](https://www.ruby-forum.com/t/fastcgi-chunked-data/210862/2 "2011-08-19T06:45:45Z")
That’s a lot of debugging when you could just have read the wiki instead: [Module ngx\_http\_fastcgi\_module](http://wiki.nginx.org/HttpFcgiModule#fastcgi_buffers) “If you want to disable buffering to disk for all replies that are greater than the FastCGI buffers and transfer data synchronously to the client set fastcgi\_max\_temp\_file\_size to 0.” Posted at Nginx Forum: > **[Re: Fastcgi chunked data](https://forum.nginx.org/read.php?2,214015,214018#msg-214018)** > > I have a fastcgi server connection that send chunks of data. I would like to have the chucks of data written to downstream, not buffered. I want to send chunked data from the server, but nginx buffers the data, I want to flush the data immediately. I... ---
**Author:** ![Shaun\_savage](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/e9a140/32.png) [@Shaun\_savage](https://www.ruby-forum.com/u/Shaun_savage)\ **Post date:** [August 19, 2011, 9:40am UTC](https://www.ruby-forum.com/t/fastcgi-chunked-data/210862/3 "2011-08-19T09:40:00Z")
Hello! On Fri, Aug 19, 2011 at 08:39:02AM +0800, Shaun savage wrote: > I have a fastcgi server connection that send chunks of data. I would > like to have the chucks of data written to downstream, not buffered. > > I want to send chunked data from the server, but nginx buffers the data, > I want to flush the data immediately. As of now nginx will always buffer fastcgi response up to full buffer (see fastcgi\_buffers directive) filled. If you really need data to be flushed immediately, you may try the patch from here: > **[upstream keepalive - call for testing](http://mailman.nginx.org/pipermail/nginx/2011-August/028324.html)** It is to address completely different problem, but as a side effect with the patch complete fastcgi records will be sent without further buffering. Maxim D. ---
**Author:** ![Shaun\_savage](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/e9a140/32.png) [@Shaun\_savage](https://www.ruby-forum.com/u/Shaun_savage)\ **Post date:** [August 19, 2011, 11:13am UTC](https://www.ruby-forum.com/t/fastcgi-chunked-data/210862/4 "2011-08-19T11:13:23Z")
I am not reading a file from disk, I am generating the data from a program. I added fastcgi\_max\_temp\_file\_size 0; but is still buffers the data in the FastCGI buffers. the size i am chunking is only 144 bytes