PrintCacheVars(8)

Name

PrintCacheVars - print the current Vesta-2 cache daemon stable variables

Synopsis

PrintCacheVars [ -verbose ]

Description

The Vesta-2 cache daemon VCache(1) keeps a few stable variables related to the weeding process. (This information is primarily of interest to maintainers who need to debug the cache daemon's deletion processing.)

deleting (boolean)

Are there pending deletions to be processed? This allows the cache daemon to resume deletions that were interrupted.

hitFilter (set of cache indecies)

The hit filter is set during the weeding process. If deleting is false, then the hit filter is an initial guess at the set of cache entries to be deleted, some of which may be kept because ongoing evaluations are using them. If deleting is true, then the hit filter is the set of cache indecies for all the cache entries to be deleted. (Note that the size of this set corresponds to the "NUM HF" column in the output of VCacheMonitor(1).)

mpksToWeed (list of multi-PK files)

The set of all the multi-PK files in which the cache entries to be deleted will be found. When the cache has re-written all of these files, the deletion process is finished.

nextMPKToWeed (index into mpksToWeed)

The cache daemon remembers its approximate place in mpksToWeed. All the multi-PK files before this have definitely been re-written. A small number of the following multi-PK files may have already been re-written, as the cache daemon does not update nextMPKToWeed after every single multi-PK file is processed. (Note that the "MPK WEED" column in the output of VCacheMonitor(1) represents the number of remaining multi-PK files in mpksToWeed starting at nextMPKToWeed.)

This inspection utility will display these variables for you.

By default, the program writes a summary by displaying only a subset of hitFilter plus its size and only displaying a few entris from nextMPKToWeed near mpksToWeed. If -verbose is specified, it prints the complete set of both hitFilter and mpksToWeed.

Example

The following is an example of the output (without using -verbose) from a cache daemon that is currently processing deletions:

deleting = true

hitFilter = 03000000201140a90d06001e55fdffff... (15168 total)

nextMPKToWeed = 1490

mpksToWeed = (6244 total)
    ...
    pfx[1479] = fe68000000000000
    pfx[1480] = 71a5000000000000
    pfx[1481] = a575000000000000
    pfx[1482] = 8bef000000000000
    pfx[1483] = cc20000000000000
    pfx[1484] = 8116000000000000
    pfx[1485] = 40e5000000000000
    pfx[1486] = b422000000000000
    pfx[1487] = cda8000000000000
    pfx[1488] = c147000000000000
    pfx[1489] = 0e9d000000000000
 >> pfx[1490] = 29ab000000000000
    pfx[1491] = 5cb7000000000000
    pfx[1492] = 5056000000000000
    pfx[1493] = dd19000000000000
    pfx[1494] = 6aa0000000000000
    pfx[1495] = 2b33000000000000
    pfx[1496] = dea1000000000000
    pfx[1497] = 9e70000000000000
    pfx[1498] = 84ea000000000000
    pfx[1499] = ab95000000000000
    pfx[1500] = 054c000000000000
    pfx[1501] = df65000000000000
    ...

Note that in the partial listing of mpksToWeed, nextMPKToWeed is marked with a preceding ">>".

Configuration Variables

PrintCacheVars locates the stable variables by reading site-specific configuration information from a Vesta-2 configuration file.

The configuration file is divided into a number of sections, denoted in the file by [SectionName]. The variables used by the PrintCacheLog are in the section denoted by [CacheServer]. Here are the variables it uses and their meanings; the types of the variables are shown in parentheses:

MetaDataRoot (string)

The pathname of the directory in which the Vesta system's metadata is stored. If this variable is undefined, the current directory is used. If defined, this path should end in a slash (/) character. Other configuration variables are interpreted relative to this path.

MetaDataDir (string)

The directory (relative to the MetaDataRoot) in which the cache server's metadata is stored. This directory should end in a slash (/) character.

StableVarsDir (string)

The directory (relative to the MetaDataRoot/MetaDataDir) in which the cache server stores its stable variables.

Deleting (string)

The file (relative to the MetaDataRoot/MetaDataDir/StableVarsDir) in which the deleting boolean is stored.

HitFilter (string)

The file (relative to the MetaDataRoot/MetaDataDir/StableVarsDir) in which the hit filter set is stored.

MPKsToWeed (string)

The file (relative to the MetaDataRoot/MetaDataDir/StableVarsDir) in which the list of multi-PK files to be processed during deletions is stored.

WeededLogDir (string)

The directory (relative to the MetaDataRoot/MetaDataDir) in which the cache server stores its log of multi-PK files which have already been re-written during deletions (i.e. where nextMPKToWeed is stored).

Files

$MetaDataRoot/$MetatDataDir/$StableVarsDir/$Deleting

Where deleting is stored.

$MetaDataRoot/$MetatDataDir/$StableVarsDir/$HitFilter

Where hitFilter is stored.

$MetaDataRoot/$MetatDataDir/$StableVarsDir/$MPKsToWeed

Where mpksToWeed is stored.

$MetaDataRoot/$MetatDataDir/$WeededLogDir/*.log

Where nextMPKToWeed is stored. It's written as a series of records indicating that N additional entries from mpksToWeed have been completed.

See Also

VCache(1), VCacheImpl(7), VCacheMonitor(1)

Author

Kenneth C. Schalk <ken AT xorian DOT net>