Mercurial > hg > nginx-site
comparison xml/en/docs/http/ngx_http_scgi_module.xml @ 1910:41cf2c2d8c5c
Cache: support for stale-while-revalidate and stale-if-error.
author | Yaroslav Zhuravlev <yar@nginx.com> |
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date | Wed, 15 Feb 2017 23:17:00 +0300 |
parents | 399d0e188195 |
children | ec4af97e4403 |
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1909:399d0e188195 | 1910:41cf2c2d8c5c |
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8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> | 8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> |
9 | 9 |
10 <module name="Module ngx_http_scgi_module" | 10 <module name="Module ngx_http_scgi_module" |
11 link="/en/docs/http/ngx_http_scgi_module.html" | 11 link="/en/docs/http/ngx_http_scgi_module.html" |
12 lang="en" | 12 lang="en" |
13 rev="30"> | 13 rev="31"> |
14 | 14 |
15 <section id="summary"> | 15 <section id="summary"> |
16 | 16 |
17 <para> | 17 <para> |
18 The <literal>ngx_http_scgi_module</literal> module allows passing | 18 The <literal>ngx_http_scgi_module</literal> module allows passing |
620 | 620 |
621 <para> | 621 <para> |
622 The <literal>error</literal> parameter also permits | 622 The <literal>error</literal> parameter also permits |
623 using a stale cached response if an SCGI server to process a request | 623 using a stale cached response if an SCGI server to process a request |
624 cannot be selected. | 624 cannot be selected. |
625 The same behavior can be enabled with the | |
626 “<link url="https://tools.ietf.org/html/rfc5861#section-4">stale-if-error</link>” | |
627 extension of the <header>Cache-Control</header> response header field (1.11.10) | |
628 for a specified number of seconds after the response became stale, | |
629 however, this has lower priority than using the directive parameter. | |
625 </para> | 630 </para> |
626 | 631 |
627 <para id="scgi_cache_use_stale_updating"> | 632 <para id="scgi_cache_use_stale_updating"> |
628 Additionally, the <literal>updating</literal> parameter permits | 633 Additionally, the <literal>updating</literal> parameter permits |
629 using a stale cached response if it is currently being updated. | 634 using a stale cached response if it is currently being updated. |
630 This allows minimizing the number of accesses to SCGI servers | 635 This allows minimizing the number of accesses to SCGI servers |
631 when updating cached data. | 636 when updating cached data. |
637 The same behavior can be enabled with the | |
638 “<link url="https://tools.ietf.org/html/rfc5861#section-3">stale-while-revalidate</link>” | |
639 extension of the <header>Cache-Control</header> response header field (1.11.10) | |
640 for a specified number of seconds after the response became stale, | |
641 however, this has lower priority than using the directive parameter. | |
632 </para> | 642 </para> |
633 | 643 |
634 <para> | 644 <para> |
635 To minimize the number of accesses to SCGI servers when | 645 To minimize the number of accesses to SCGI servers when |
636 populating a new cache element, the <link id="scgi_cache_lock"/> | 646 populating a new cache element, the <link id="scgi_cache_lock"/> |