Commit 31091fba authored by Vincent Pelletier's avatar Vincent Pelletier

Document --period associated behaviour.

parent 68a0beb7
...@@ -198,6 +198,52 @@ Portability note: the use of paths containing directory elements inside ...@@ -198,6 +198,52 @@ Portability note: the use of paths containing directory elements inside
configuration files is discouraged, as it's not portable. This may change configuration files is discouraged, as it's not portable. This may change
later (ex: deciding that import paths are URLs and applying their rules). later (ex: deciding that import paths are URLs and applying their rules).
Periods
=======
When providing the `--period` argument, two related settings are affected:
- the period represented by each point in a graph (most important for the
hit graph, as it represents the number of hits per such period)
- the period represented by each column in per-period tables (status codes
per date, hits per day...)
Also, when `--period` is not provided, apachedex uses a threshold to tell
when to switch to the larger period. That period was chosen to correspond
to 200 graph points, which represents a varying number of table columns.
.. table :: Details of `--period` argument
======== ======= ======= ============== =========================
--period graph table to next period columns until next period
======== ======= ======= ============== =========================
day hour day 200 hours 9 (8.3 days)
week 6 hours week 1200 hours 8 (7.1 weeks)
month day month 5000 hours 7 (~6.7 months)
quarter 7 days quarter 1400 days 16 (15.3 weeks)
year month year (n/a) (infinity)
======== ======= ======= ============== =========================
"7 days" period used in `--period quarter` are not weeks strictly
speaking: a week starts a monday/sunday, pendending on the locale.
"7 days" start on the first day of the year, for simplicity - and
performance. "week" used for `--period week` are really weeks, although
starting on monday independently from locale.
When there are no hits for more than a graph period, placeholders are
generated at 0 hit value (which is the reality) and 100% apdex (this is
arbitrary). Those placeholders only affect graphs, and do not affect
averages nor table content.
Because not all graph periods are actually equal in length (because of
leap seconds, DST, leap years, year containing a non-integer number of
weeks), some hit graph points are artificially corrected against these
effects. Here also, the correction only affects graphs, neither averages
nor table content. For example, on non-leap years, the last year's
"7 days" period lasts a single day. Ploted hit count is then multiplied
by 7 (and 3.5 on leap years).
Performance Performance
=========== ===========
...@@ -232,11 +278,6 @@ For better performance... ...@@ -232,11 +278,6 @@ For better performance...
Notes Notes
===== =====
When there are no hits for more than a graph period, placeholders are
generated for 0 hit (which is the reality) and 100% apdex (this is
arbitrary). Those placeholders only affect graphs, and do not affect
averages nor table content.
Loading saved states generated with different sets of parameters is not Loading saved states generated with different sets of parameters is not
prevented, but can produce nonsense/unreadable results. Or it can save the day prevented, but can produce nonsense/unreadable results. Or it can save the day
if you do want to mix different parameters (ex: you have some logs generated if you do want to mix different parameters (ex: you have some logs generated
......
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