not serving cached/optimized content

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Lefteris Skoulas

Nov 9, 2021, 7:27:10 AM11/9/21
to mod-pagespeed-discuss
I am trying to take advantage of the pagespeed module in my apache webserver for my wordpress ecommerce shop.
Its a dedicated server with root access.
Centos7.9 OS with plesk controlpanel installed.
using php7.4.x version.
Stackpath cdn is enabled and configured.

My structure is :

Apache directory root for WP: /var/www/vhosts/mydomain.tld/httpdocs

My wordpress image directory is via cdn https://mycdnurl.tld/wp-content' );
My plugins directory is loaded via a seperate subdomain hosted on the same server.

All related domains/subdomains are authorised in my httpd.conf

My problem is that in order to serve the optimized webp images/css/js i have to refresh the browser 2-3 times.
sometimes colors, background or even simple html elements are disappearing and appearing immediately after, very quick

What do i have to do in order to always serve the optimized pagespeed files?
Based on my pagespeed.conf or the existance of the cdn, am i doing anything wrong?

My config:

# Attempt to load mod_version if it wasn't loaded or compiled in (eg on Debian)
<IfModule !mod_version.c>
  LoadModule version_module /usr/lib64/httpd/modules/

<IfVersion < 2.4>
  LoadModule pagespeed_module /usr/lib64/httpd/modules/
<IfVersion >= 2.4.2>
  # As default pagespeed.conf configuration uses old-style ACLs using
  # 'allow' and 'deny', we load mod_access_compat in Apache 2.4. If that's a
  # problem, the blocks using that can be converted to the newer 'Require'
  # syntax.
  <IfModule !access_compat_module>
    LoadModule access_compat_module /usr/lib64/httpd/modules/

  LoadModule pagespeed_module /usr/lib64/httpd/modules/

# Only attempt to load mod_deflate if it hasn't been loaded already.
<IfModule !mod_deflate.c>
 LoadModule deflate_module /usr/lib64/httpd/modules/
<IfModule pagespeed_module>
    # Turn on mod_pagespeed. To completely disable mod_pagespeed, you
    # can set this to "off".
    ModPagespeed on

    # Direct Apache to send all HTML output to the mod_pagespeed
    # output handler.
    AddOutputFilterByType MOD_PAGESPEED_OUTPUT_FILTER text/html

    # If you want mod_pagespeed process XHTML as well, please uncomment this
    # line.
    AddOutputFilterByType MOD_PAGESPEED_OUTPUT_FILTER application/xhtml+xml

    # The ModPagespeedFileCachePath directory must exist and be writable
    # by the apache user (as specified by the User directive).
    ModPagespeedFileCachePath            "/var/cache/mod_pagespeed/"

    # LogDir is needed to store various logs, including the statistics log
    # required for the console.
    ModPagespeedLogDir "/var/log/pagespeed"

    # The locations of SSL Certificates is distribution-dependent.
    ModPagespeedSslCertDirectory "/etc/pki/tls/certs"
    ModPagespeedSslCertFile /etc/pki/tls/cert.pem

    # If you want, you can use one or more memcached servers as the store for
    # the mod_pagespeed cache.
    # ModPagespeedMemcachedServers localhost:11211
       #ModPagespeedRedisServer ""

    # A portion of the cache can be kept in memory only, to reduce load on disk
    # (or memcached) from many small files.
    ModPagespeedCreateSharedMemoryMetadataCache "/var/cache/mod_pagespeed/" 51200

  ModPagespeedFileCachePath "/var/cache/pagespeed/"

  ModPagespeedFileCachePath "/var/cache/pagespeed/"

    # Override the mod_pagespeed 'rewrite level'. The default level
    # "CoreFilters" uses a set of rewrite filters that are generally
    # safe for most web pages. Most sites should not need to change
    # this value and can instead fine-tune the configuration using the
    # ModPagespeedDisableFilters and ModPagespeedEnableFilters
    # directives, below. Valid values for ModPagespeedRewriteLevel are
    # PassThrough, CoreFilters and TestingCoreFilters.
    ModPagespeedRewriteLevel PassThrough

    # Explicitly disables specific filters. This is useful in
    # conjuction with ModPagespeedRewriteLevel. For instance, if one
    # of the filters in the CoreFilters needs to be disabled for a
    # site, that filter can be added to
    # ModPagespeedDisableFilters. This directive contains a
    # comma-separated list of filter names, and can be repeated.
    # ModPagespeedDisableFilters rewrite_images

    # Explicitly enables specific filters. This is useful in
    # conjuction with ModPagespeedRewriteLevel. For instance, filters
    # not included in the CoreFilters may be enabled using this
    # directive. This directive contains a comma-separated list of
    # filter names, and can be repeated.
    ModPagespeedEnableFilters rewrite_javascript,rewrite_css
    ModPagespeedEnableFilters collapse_whitespace,elide_attributes

    # Explicitly forbids the enabling of specific filters using either query
    # parameters or request headers. This is useful, for example, when we do
    # not want the filter to run for performance or security reasons. This
    # directive contains a comma-separated list of filter names, and can be
    # repeated.
    # ModPagespeedForbidFilters rewrite_images

    # How long mod_pagespeed will wait to return an optimized resource
    # (per flush window) on first request before giving up and returning the
    # original (unoptimized) resource. After this deadline is exceeded the
    # original resource is returned and the optimization is pushed to the
    # background to be completed for future requests. Increasing this value will
    # increase page latency, but might reduce load time (for instance on a
    # bandwidth-constrained link where it's worth waiting for image
    # compression to complete). If the value is less than or equal to zero
    # mod_pagespeed will wait indefinitely for the rewrite to complete before
    # returning.
    # ModPagespeedRewriteDeadlinePerFlushMs 10

    # ModPagespeedDomain
    # authorizes rewriting of JS, CSS, and Image files found in this
    # domain. By default only resources with the same origin as the
    # HTML file are rewritten. For example:
    #   ModPagespeedDomain
    # This will allow resources found on to be
    # rewritten in addition to those in the same domain as the HTML.
    # Other domain-related directives (like ModPagespeedMapRewriteDomain
    # and ModPagespeedMapOriginDomain) can also authorize domains.
    # Wildcards (* and ?) are allowed in the domain specification. Be
    # careful when using them as if you rewrite domains that do not
    # send you traffic, then the site receiving the traffic will not
    # know how to serve the rewritten content.

    # If you use downstream caches such as varnish or proxy_cache for caching
    # HTML, you can configure pagespeed to work with these caches correctly
    # using the following directives. Note that the values for
    # ModPagespeedDownstreamCachePurgeLocationPrefix and
    # ModPagespeedDownstreamCacheRebeaconingKey are deliberately left empty here
    # in order to force the webmaster to choose appropriate value for these.
    # ModPagespeedDownstreamCachePurgeLocationPrefix
    # ModPagespeedDownstreamCachePurgeMethod PURGE
    # ModPagespeedDownstreamCacheRewrittenPercentageThreshold 95
    # ModPagespeedDownstreamCacheRebeaconingKey
       ModPagespeedEnableCachePurge on

    # Other defaults (cache sizes and thresholds):
    ModPagespeedFileCacheSizeKb          102400
    ModPagespeedFileCacheCleanIntervalMs 3600000
    ModPagespeedLRUCacheKbPerProcess     1024
    ModPagespeedLRUCacheByteLimit        16384
    ModPagespeedCssFlattenMaxBytes       102400
    ModPagespeedCssImageInlineMaxBytes   0
    ModPagespeedImageInlineMaxBytes      100000
    ModPagespeedCssOutlineMinBytes       100000
    ModPagespeedJsOutlineMinBytes        100000
    ModPagespeedMaxCombinedCssBytes      -1
    ModPagespeedMaxCombinedJsBytes       100000

    # Limit the number of inodes in the file cache. Set to 0 for no limit.
    # The default value if this paramater is not specified is 0 (no limit).
    ModPagespeedFileCacheInodeLimit        500000

    # Bound the number of images that can be rewritten at any one time; this
    # avoids overloading the CPU.  Set this to -1 to remove the bound.
    # ModPagespeedImageMaxRewritesAtOnce      8

    # You can also customize the number of threads per Apache process
    # mod_pagespeed will use to do resource optimization. Plain
    # "rewrite threads" are used to do short, latency-sensitive work,
    # while "expensive rewrite threads" are used for actual optimization
    # work that's more computationally expensive. If you live these unset,
    # or use values <= 0 the defaults will be used, which is 1 for both
    # values when using non-threaded MPMs (e.g. prefork) and 4 for both
    # on threaded MPMs (e.g. worker and event). These settings can only
    # be changed globally, and not per virtual host.
    ModPagespeedNumRewriteThreads 32
    ModPagespeedNumExpensiveRewriteThreads 32

    # Randomly drop rewrites (*) to increase the chance of optimizing
    # frequently fetched resources and decrease the chance of optimizing
    # infrequently fetched resources. This can reduce CPU load. The default
    # value of this parameter is 0 (no drops).  90 means that a resourced
    # fetched once has a 10% probability of being optimized while a resource
    # that is fetched 50 times has a 99.65% probability of being optimized.
    # (*) Currently only CSS files and images are randomly dropped.  Images
    # within CSS files are not randomly dropped.
    # ModPagespeedRewriteRandomDropPercentage 90

    # Many filters modify the URLs of resources in HTML files. This is typically
    # harmless but pages whose Javascript expects to read or modify the original
    # URLs may break. The following parameters prevent filters from modifying
    # URLs of their respective types.
    # ModPagespeedJsPreserveURLs on
    # ModPagespeedImagePreserveURLs on
    # ModPagespeedCssPreserveURLs on

    # When PreserveURLs is on, it is still possible to enable browser-specific
    # optimizations (for example, webp images can be served to browsers that
    # will accept them).  They'll be served with Vary: Accept or Vary:
    # User-Agent headers as appropriate.  Note that this may require configuring
    # reverse proxy caches such as varnish to handle these headers properly.
    ModPagespeedEnableFilters in_place_optimize_for_browser

    # Internet Explorer has difficulty caching resources with Vary: headers.
    # They will either be uncached (older IE) or require revalidation.  See:
    # As a result we serve them as Cache-Control: private instead by default.
    # If you are using a reverse proxy or CDN configured to cache content with
    # the Vary: Accept header you should turn this setting off.
    # ModPagespeedPrivateNotVaryForIE on

    # Settings for image optimization:
    # Lossy image recompression quality (0 to 100, -1 just strips metadata):
    # ModPagespeedImageRecompressionQuality 85
    # Jpeg recompression quality (0 to 100, -1 uses ImageRecompressionQuality):
    ModPagespeedJpegRecompressionQuality -1
    ModPagespeedJpegRecompressionQualityForSmallScreens 70
    # WebP recompression quality (0 to 100, -1 uses ImageRecompressionQuality):
    ModPagespeedWebpRecompressionQuality 80
    ModPagespeedWebpRecompressionQualityForSmallScreens 70
    # Timeout for conversions to WebP format, in
    # milliseconds. Negative values mean no timeout is applied. The
    # default value is -1:
    #ModPagespeedWebpTimeoutMs -1
    # Percent of original image size below which optimized images are retained:
    ModPagespeedImageLimitOptimizedPercent 100
    # Percent of original image area below which image resizing will be
    # attempted:
    ModPagespeedImageLimitResizeAreaPercent 100

    # Settings for inline preview images
    # Setting this to n restricts preview images to the first n images found on
    # the page.  The default of -1 means preview images can appear anywhere on
    # the page (if those images appear above the fold).
    ModPagespeedMaxInlinedPreviewImagesIndex -1

    # Sets the minimum size in bytes of any image for which a low quality image
    # is generated.
    # ModPagespeedMinImageSizeLowResolutionBytes 3072

    # The maximum URL size is generally limited to about 2k characters
    # Apache servers by default impose a further limitation of about
    # 250 characters per URL segment (text between slashes).
    # mod_pagespeed circumvents this limitation, but if you employ
    # proxy servers in your path you may need to re-impose it by
    # overriding the setting here.  The default setting is 1024
    # characters.
    #ModPagespeedMaxSegmentLength 2048

    # Uncomment this if you want to prevent mod_pagespeed from combining files
    # (e.g. CSS files) across paths
    # ModPagespeedCombineAcrossPaths off

    # Renaming JavaScript URLs can sometimes break them.  With this
    # option enabled, mod_pagespeed uses a simple heuristic to decide
    # not to rename JavaScript that it thinks is introspective.
    # You can uncomment this to let mod_pagespeed rename all JS files.
    # ModPagespeedAvoidRenamingIntrospectiveJavascript off

    # Certain common JavaScript libraries are available from Google, which acts
    # as a CDN and allows you to benefit from browser caching if a new visitor
    # to your site previously visited another site that makes use of the same
    # libraries as you do.  Enable the following filter to turn on this feature.
    ModPagespeedEnableFilters canonicalize_javascript_libraries

    # The following line configures a library that is recognized by
    # canonicalize_javascript_libraries.  This will have no effect unless you
    # enable this filter (generally by uncommenting the last line in the
    # previous stanza).  The format is:
    #    ModPagespeedLibrary bytes md5 canonical_url
    # Where bytes and md5 are with respect to the *minified* JS; use
    # js_minify --print_size_and_hash to obtain this data.
    # Note that we can register multiple hashes for the same canonical url;
    # we do this if there are versions available that have already been minified
    # with more sophisticated tools.
    # Additional library configuration can be found in
    # pagespeed_libraries.conf included in the distribution.  You should add
    # new entries here, though, so that file can be automatically upgraded.
    # ModPagespeedLibrary 43 1o978_K0_LNE5_ystNklf

    # Explicitly tell mod_pagespeed to load some resources from disk.
    # This will speed up load time and update frequency.
    # This should only be used for static resources which do not need
    # specific headers set or other processing by Apache.
    # Both URL and filesystem path should specify directories and
    # filesystem path must be absolute (for now).
    # ModPagespeedLoadFromFile "" "/var/www/static/"

    # Enables server-side instrumentation and statistics.  If this rewriter is
    # enabled, then each rewritten HTML page will have instrumentation javacript
    # added that sends latency beacons to /mod_pagespeed_beacon.  These
    # statistics can be accessed at /mod_pagespeed_statistics.  You must also
    # enable the mod_pagespeed_statistics and mod_pagespeed_beacon handlers
    # below.
    ModPagespeedEnableFilters add_instrumentation

    # The add_instrumentation filter sends a beacon after the page onload
    # handler is called. The user might navigate to a new URL before this. If
    # you enable the following directive, the beacon is sent as part of an
    # onbeforeunload handler, for pages where navigation happens before the
    # onload event.
    # ModPagespeedReportUnloadTime on

    # Uncomment the following line so that ModPagespeed will not cache or
    # rewrite resources with Vary: in the header, e.g. Vary: User-Agent.
    # Note that ModPagespeed always respects Vary: headers on html content.
    # ModPagespeedRespectVary on

    # Uncomment the following line if you want to disable statistics entirely.
    # ModPagespeedStatistics off

    # These handlers are central entry-points into the admin pages.
    # By default, pagespeed_admin and pagespeed_global_admin present
    # the same data, and differ only when
    # ModPagespeedUsePerVHostStatistics is enabled.  In that case,
    # /pagespeed_global_admin sees aggregated data across all vhosts,
    # and the /pagespeed_admin sees data only for a particular vhost.
    # You may insert other "Allow from" lines to add hosts you want to
    # allow to look at generated statistics.  Another possibility is
    # to comment out the "Order" and "Allow" options from the config
    # file, to allow any client that can reach your server to access
    # and change server state, such as statistics, caches, and
    # messages.  This might be appropriate in an experimental setup.
    <Location /pagespeed_admin>
        Order allow,deny
        Allow from localhost
        Allow from
        SetHandler pagespeed_admin
    <Location /pagespeed_global_admin>
        Order allow,deny
        Allow from localhost
        Allow from
        SetHandler pagespeed_global_admin

    # Enable logging of mod_pagespeed statistics, needed for the console.
    ModPagespeedStatisticsLogging on

    # Page /mod_pagespeed_message lets you view the latest messages from
    # mod_pagespeed, regardless of log-level in your httpd.conf
    # ModPagespeedMessageBufferSize is the maximum number of bytes you would
    # like to dump to your /mod_pagespeed_message page at one time,
    # its default value is 100k bytes.
    # Set it to 0 if you want to disable this feature.
    ModPagespeedMessageBufferSize 100000
    ModPagespeedImageMaxRewritesAtOnce -1

ModPagespeedEnableFilters remove_quotes
ModPagespeedEnableFilters elide_attributes
ModPagespeedEnableFilters remove_comments
ModPagespeedEnableFilters extend_cache
ModPagespeedForceCaching on
ModPagespeedEnableFilters make_google_analytics_async
ModPagespeedEnableFilters local_storage_cache
ModPagespeedEnableFilters inline_css
ModPagespeedEnableFilters inline_javascript
ModPagespeedLazyloadImagesAfterOnload off
ModPagespeedLazyloadImagesBlankUrl ""
ModPagespeedEnableFilters prioritize_critical_css
ModPagespeedEnableFilters collapse_whitespace
ModPagespeedEnableFilters recompress_images
ModPagespeedEnableFilters convert_jpeg_to_progressive
ModPagespeedEnableFilters convert_gif_to_png
ModPagespeedEnableFilters convert_to_webp_lossless
ModPagespeedEnableFilters trim_urls
ModPagespeedEnableFilters strip_image_color_profile
ModPagespeedEnableFilters strip_image_meta_data
ModPagespeedEnableFilters jpeg_subsampling
ModPagespeedEnableFilters convert_png_to_jpeg
ModPagespeedEnableFilters resize_images
ModPagespeedEnableFilters resize_rendered_image_dimensions
ModPagespeedEnableFilters convert_jpeg_to_webp
ModPagespeedEnableFilters convert_to_webp_animated
ModPagespeedEnableFilters convert_to_webp_lossless

ModPagespeedImageRecompressionQuality 85

ModPagespeedRespectXForwardedProto on

ModPagespeedEnableFilters insert_dns_prefetch
ModPagespeedEnableFilters hint_preload_subresources
ModPagespeedDomain *

ModPagespeedCssFlattenMaxBytes 100000
ModPagespeedCssInlineMaxBytes 1000000
ModPagespeedGoogleFontCssInlineMaxBytes 100000
ModPagespeedJsInlineMaxBytes 100000
ModPagespeedCssFlattenMaxBytes 100000
ModPagespeedEnableFilters lazyload_images
ModPagespeedLazyloadImagesAfterOnload off
ModPagespeedLazyloadImagesBlankUrl ""
ModPagespeedEnableFilters trim_urls
ModPagespeedFetchHttps enable


pagespeed debug doesn't report anything preventing optimizing content.


Nov 9, 2021, 3:37:55 PM11/9/21
to mod-pagespeed-discuss
Can you share a url to test?

You have the VirtualHost in <IfModule pagespeed_module>block, so if the module don´t load, you have no web.
I suspect this not the whole apache config, even you need to include .htaccess file, because in this file can be rewrite rules that interfere whit pagespeed.

But, Ockham`s razor:

If the optimized resourse, the that have pagespeed in the url take times to appear and then disappear and restart the optimization process again....
What are you cache-control headers?
If you have a cache-control header for 5 mi (300 sec), some like cache-control: max-age=300, the the optimiation process must restart every 5 min.
and the optimization process take some time, to get all resources optimized take 2 or 3 hits.

Resorces need to be public cacheable aka no "private" "max-age=0" o things like it.

George Vasiliadis

Jan 19, 2022, 2:01:36 PM1/19/22
to mod-pagespeed-discuss
Well, this config it's kinda complicated about the way you place the EnabledFilters but this it's not the problem. First of all you have to remove the # from     # ModPagespeedImageMaxRewritesAtOnce      8
line to allow more files for optimization at once. 

If you can share a URL to examinate!

στείλε μου σε προσωπικό αν έχεις θέμα να το δημοσιεύσεις.
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