Please help: error establishing a database connection bluehost wordpress

now days some times showing “error establishing a database connection bluehost wordpress”

i got message from bluehost site using 16% of a CPU

please check my htaccess

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# BEGIN WP-PICShield
# Header always append X-Frame-Options SAMEORIGIN
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_URI} \.(jpg|jpeg|png|gif)$ [NC]
RewriteCond %{REMOTE_ADDR} !^(127.0.0.1|173.254.107.237)$ [NC]
RewriteCond %{REMOTE_ADDR} !^66.6.(32|33|36|44|45|46|40). [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?(www.website.com|translate.google.com|translate.googleusercontent.com|www.microsofttranslator.com|pinterest.com|tumblr.com|facebook.com|plus.google|twitter.com|googleapis.com|googleusercontent.com|ytimg.com|gstatic.com) [NC]
RewriteCond %{HTTP_USER_AGENT} !(googlebot|msnbot|baiduspider|slurp|webcrawler|teoma|photon|facebookexternalhit|facebookplatform|pinterest|feedfetcher|ggpht) [NC]
RewriteCond %{HTTP_USER_AGENT} !(photon|smush.it|akamai|cloudfront|netdna|bitgravity|maxcdn|edgecast|limelight|tineye) [NC]
RewriteCond %{HTTP_USER_AGENT} !(developers|gstatic|googleapis|googleusercontent|google|ytimg) [NC]
RewriteRule (.*) byrev-wp-picshield.php?key=oSu0-AXIf&src=$1 [L]
</IfModule>
# END WP-PICShield
# BEGIN W3TC Browser Cache
<IfModule mod_mime.c>
    AddType text/css .css
    AddType text/x-component .htc
    AddType application/x-javascript .js
    AddType application/javascript .js2
    AddType text/javascript .js3
    AddType text/x-js .js4
    AddType text/html .html .htm
    AddType text/richtext .rtf .rtx
    AddType image/svg+xml .svg .svgz
    AddType text/plain .txt
    AddType text/xsd .xsd
    AddType text/xsl .xsl
    AddType text/xml .xml
    AddType video/asf .asf .asx .wax .wmv .wmx
    AddType video/avi .avi
    AddType image/bmp .bmp
    AddType application/java .class
    AddType video/divx .divx
    AddType application/msword .doc .docx
    AddType application/vnd.ms-fontobject .eot
    AddType application/x-msdownload .exe
    AddType image/gif .gif
    AddType application/x-gzip .gz .gzip
    AddType image/x-icon .ico
    AddType image/jpeg .jpg .jpeg .jpe
    AddType application/json .json
    AddType application/vnd.ms-access .mdb
    AddType audio/midi .mid .midi
    AddType video/quicktime .mov .qt
    AddType audio/mpeg .mp3 .m4a
    AddType video/mp4 .mp4 .m4v
    AddType video/mpeg .mpeg .mpg .mpe
    AddType application/vnd.ms-project .mpp
    AddType application/x-font-otf .otf
    AddType application/vnd.oasis.opendocument.database .odb
    AddType application/vnd.oasis.opendocument.chart .odc
    AddType application/vnd.oasis.opendocument.formula .odf
    AddType application/vnd.oasis.opendocument.graphics .odg
    AddType application/vnd.oasis.opendocument.presentation .odp
    AddType application/vnd.oasis.opendocument.spreadsheet .ods
    AddType application/vnd.oasis.opendocument.text .odt
    AddType audio/ogg .ogg
    AddType application/pdf .pdf
    AddType image/png .png
    AddType application/vnd.ms-powerpoint .pot .pps .ppt .pptx
    AddType audio/x-realaudio .ra .ram
    AddType application/x-shockwave-flash .swf
    AddType application/x-tar .tar
    AddType image/tiff .tif .tiff
    AddType application/x-font-ttf .ttf .ttc
    AddType audio/wav .wav
    AddType audio/wma .wma
    AddType application/vnd.ms-write .wri
    AddType application/vnd.ms-excel .xla .xls .xlsx .xlt .xlw
    AddType application/zip .zip
</IfModule>
<IfModule mod_expires.c>
    ExpiresActive On
    ExpiresByType text/css A31536000
    ExpiresByType text/x-component A31536000
    ExpiresByType application/x-javascript A31536000
    ExpiresByType application/javascript A31536000
    ExpiresByType text/javascript A31536000
    ExpiresByType text/x-js A31536000
    ExpiresByType text/html A7200
    ExpiresByType text/richtext A7200
    ExpiresByType image/svg+xml A7200
    ExpiresByType text/plain A7200
    ExpiresByType text/xsd A7200
    ExpiresByType text/xsl A7200
    ExpiresByType text/xml A7200
    ExpiresByType video/asf A31536000
    ExpiresByType video/avi A31536000
    ExpiresByType image/bmp A31536000
    ExpiresByType application/java A31536000
    ExpiresByType video/divx A31536000
    ExpiresByType application/msword A31536000
    ExpiresByType application/vnd.ms-fontobject A31536000
    ExpiresByType application/x-msdownload A31536000
    ExpiresByType image/gif A31536000
    ExpiresByType application/x-gzip A31536000
    ExpiresByType image/x-icon A31536000
    ExpiresByType image/jpeg A31536000
    ExpiresByType application/json A31536000
    ExpiresByType application/vnd.ms-access A31536000
    ExpiresByType audio/midi A31536000
    ExpiresByType video/quicktime A31536000
    ExpiresByType audio/mpeg A31536000
    ExpiresByType video/mp4 A31536000
    ExpiresByType video/mpeg A31536000
    ExpiresByType application/vnd.ms-project A31536000
    ExpiresByType application/x-font-otf A31536000
    ExpiresByType application/vnd.oasis.opendocument.database A31536000
    ExpiresByType application/vnd.oasis.opendocument.chart A31536000
    ExpiresByType application/vnd.oasis.opendocument.formula A31536000
    ExpiresByType application/vnd.oasis.opendocument.graphics A31536000
    ExpiresByType application/vnd.oasis.opendocument.presentation A31536000
    ExpiresByType application/vnd.oasis.opendocument.spreadsheet A31536000
    ExpiresByType application/vnd.oasis.opendocument.text A31536000
    ExpiresByType audio/ogg A31536000
    ExpiresByType application/pdf A31536000
    ExpiresByType image/png A31536000
    ExpiresByType application/vnd.ms-powerpoint A31536000
    ExpiresByType audio/x-realaudio A31536000
    ExpiresByType image/svg+xml A31536000
    ExpiresByType application/x-shockwave-flash A31536000
    ExpiresByType application/x-tar A31536000
    ExpiresByType image/tiff A31536000
    ExpiresByType application/x-font-ttf A31536000
    ExpiresByType audio/wav A31536000
    ExpiresByType audio/wma A31536000
    ExpiresByType application/vnd.ms-write A31536000
    ExpiresByType application/vnd.ms-excel A31536000
    ExpiresByType application/zip A31536000
</IfModule>
<IfModule mod_deflate.c>
    <IfModule mod_headers.c>
        Header append Vary User-Agent env=!dont-vary
    </IfModule>
        AddOutputFilterByType DEFLATE text/css text/x-component application/x-javascript application/javascript text/javascript text/x-js text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon application/json
    <IfModule mod_mime.c>
        # DEFLATE by extension
        AddOutputFilter DEFLATE js css htm html xml
    </IfModule>
</IfModule>
<FilesMatch "\.(css|htc|js|js2|js3|js4|CSS|HTC|JS|JS2|JS3|JS4)$">
    FileETag MTime Size
    <IfModule mod_headers.c>
        Header set Pragma "public"
        Header append Cache-Control "public"
         Header set X-Powered-By "W3 Total Cache/0.9.3"
    </IfModule>
</FilesMatch>
<FilesMatch "\.(html|htm|rtf|rtx|svg|svgz|txt|xsd|xsl|xml|HTML|HTM|RTF|RTX|SVG|SVGZ|TXT|XSD|XSL|XML)$">
    FileETag MTime Size
    <IfModule mod_headers.c>
        Header set Pragma "public"
        Header append Cache-Control "public"
         Header set X-Powered-By "W3 Total Cache/0.9.3"
    </IfModule>
</FilesMatch>
<FilesMatch "\.(asf|asx|wax|wmv|wmx|avi|bmp|class|divx|doc|docx|eot|exe|gif|gz|gzip|ico|jpg|jpeg|jpe|json|mdb|mid|midi|mov|qt|mp3|m4a|mp4|m4v|mpeg|mpg|mpe|mpp|otf|odb|odc|odf|odg|odp|ods|odt|ogg|pdf|png|pot|pps|ppt|pptx|ra|ram|svg|svgz|swf|tar|tif|tiff|ttf|ttc|wav|wma|wri|xla|xls|xlsx|xlt|xlw|zip|ASF|ASX|WAX|WMV|WMX|AVI|BMP|CLASS|DIVX|DOC|DOCX|EOT|EXE|GIF|GZ|GZIP|ICO|JPG|JPEG|JPE|JSON|MDB|MID|MIDI|MOV|QT|MP3|M4A|MP4|M4V|MPEG|MPG|MPE|MPP|OTF|ODB|ODC|ODF|ODG|ODP|ODS|ODT|OGG|PDF|PNG|POT|PPS|PPT|PPTX|RA|RAM|SVG|SVGZ|SWF|TAR|TIF|TIFF|TTF|TTC|WAV|WMA|WRI|XLA|XLS|XLSX|XLT|XLW|ZIP)$">
    FileETag MTime Size
    <IfModule mod_headers.c>
        Header set Pragma "public"
        Header append Cache-Control "public"
         Header set X-Powered-By "W3 Total Cache/0.9.3"
    </IfModule>
</FilesMatch>
# END W3TC Browser Cache
# BEGIN W3TC Page Cache core
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteCond %{HTTPS} =on
    RewriteRule .* - [E=W3TC_SSL:_ssl]
    RewriteCond %{SERVER_PORT} =443
    RewriteRule .* - [E=W3TC_SSL:_ssl]
    RewriteCond %{HTTP:Accept-Encoding} gzip
    RewriteRule .* - [E=W3TC_ENC:_gzip]
    RewriteCond %{REQUEST_METHOD} !=POST
    RewriteCond %{QUERY_STRING} =""
    RewriteCond %{REQUEST_URI} \/$
    RewriteCond %{HTTP_COOKIE} !(comment_author|wp-postpass|w3tc_logged_out|wordpress_logged_in|wptouch_switch_toggle) [NC]
    RewriteCond "%{DOCUMENT_ROOT}/wp-content/cache/page_enhanced/%{HTTP_HOST}/%{REQUEST_URI}/_index%{ENV:W3TC_SSL}.html%{ENV:W3TC_ENC}" -f
    RewriteRule .* "/wp-content/cache/page_enhanced/%{HTTP_HOST}/%{REQUEST_URI}/_index%{ENV:W3TC_SSL}.html%{ENV:W3TC_ENC}" [L]
</IfModule>
# END W3TC Page Cache core
# BEGIN W3TC Skip 404 error handling by WordPress for static files
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} !(robots\.txt|sitemap(_index)?\.xml(\.gz)?|[a-z0-9_\-]+-sitemap([0-9]+)?\.xml(\.gz)?)
    RewriteCond %{REQUEST_FILENAME} \.(css|htc|js|js2|js3|js4|html|htm|rtf|rtx|svg|svgz|txt|xsd|xsl|xml|asf|asx|wax|wmv|wmx|avi|bmp|class|divx|doc|docx|eot|exe|gif|gz|gzip|ico|jpg|jpeg|jpe|json|mdb|mid|midi|mov|qt|mp3|m4a|mp4|m4v|mpeg|mpg|mpe|mpp|otf|odb|odc|odf|odg|odp|ods|odt|ogg|pdf|png|pot|pps|ppt|pptx|ra|ram|svg|svgz|swf|tar|tif|tiff|ttf|ttc|wav|wma|wri|xla|xls|xlsx|xlt|xlw|zip)$ [NC]
    RewriteRule .* - [L]
</IfModule>
# END W3TC Skip 404 error handling by WordPress for static files