DAX fallbacks


 
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Operating Systems Solaris DAX fallbacks
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Old 07-26-2018
Oracle DAX fallbacks

Hi,

could you explain what DAX fallbacks mean in detail and how to avoid them? Or is it ok to have fallbacks?

Unfortunately googling does not help...



MANpage says: fallbacks == Number of commands completed by the software, which DAX could not complete



OK, but why and what does it mean for the DB?



Running RAC on M7 with InMemory:

1st node=DAX commands 35.608.411 with 18 fallbacks

2nd node=DAX commands 63.563.607 with 2.656.188 fallbacks



Is it just a bad day for the second node? Any ideas how I could dig deeper at OS or DB level?



Thanks in advance and regards

- Martin
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PEGASUS-CONFIG(1)														 PEGASUS-CONFIG(1)

NAME
pegasus-config - The authority for where parts of the Pegasus system exists on the filesystem. pegasus-config can be used to find libraries such as the DAX generators. SYNOPSIS
pegasus-config [-h] [--help] [-V] [--version] [--noeoln] [--perl-dump] [--perl-hash] [--python-dump] [--sh-dump] [--bin] [--conf] [--java] [--perl] [--python] [--python-externals] [--schema] [--classpath] [--local-site] [--full-local] DESCRIPTION
pegasus-config is used to find locations of Pegasus system components. The tool is used internally in Pegasus and by users who need to find paths for DAX generator libraries and schemas. OPTIONS
-h, --help Prints help and exits. -V, --version Prints Pegasus version information --perl-dump Dumps all settings in perl format as separate variables. --perl-hash Dumps all settings in perl format as single perl hash. --python-dump Dumps all settings in python format. --sh-dump Dumps all settings in shell format. --bin Print the directory containing Pegasus binaries. --conf Print the directory containing configuration files. --java Print the directory containing the jars. --perl Print the directory to include into your PERL5LIB. --python Print the directory to include into your PYTHONLIB. --python-externals Print the directory to the external Python libraries. --schema Print the directory containing schemas. --classpath Builds a classpath containing the Pegasus jars. --noeoln Do not produce a end-of-line after output. This is useful when being called from non-shell backticks in scripts. However, order is important for this option: If you intend to use it, specify it first. --local-site [d] Create a site catalog entry for site "local". This is only an XML snippet without root element nor XML headers. The optional argument "d" points to the mount point to use. If not specified, defaults to the user's $HOME directory. --full-local [d] Create a complete site catalog with only site "local". The an XML snippet without root element nor XML headers. The optional argument "d" points to the mount point to use. If not specified, defaults to the user's $HOME directory. EXAMPLE
To set the PYTHONPATH variable in your shell for using the Python DAX API: export PYTHONPATH=`pegasus-config --python` To set the same path inside Python: config = subprocess.Popen("pegasus-config --python-dump", stdout=subprocess.PIPE, shell=True).communicate()[0] exec config To set the PERL5LIB variable in your shell for using the Perl DAX API: export PERL5LIB=`pegasus-config --perl` To set the same path inside Perl: eval `pegasus-config --perl-dump`; die("Unable to eval pegasus-config output: $@") if $@; will set variables a number of lexically local-scoped my variables with prefix "pegasus_" and expand Perl's search path for this script. Alternatively, you can fail early and collect all Pegasus-related variables into a single global %pegasus variable for convenience: BEGIN { eval `pegasus-config --perl-hash`; die("Unable to eval pegasus-config output: $@") if $@; } AUTHOR
Pegasus Team http://pegasus.isi.edu 05/24/2012 PEGASUS-CONFIG(1)