There are edge cases where rounding a date to a certain interval using a time
zone with DST shifts can currently cause the rounded date to be bigger than the
original date. This happens when rounding a date closely after a DST start and
the rounded date falls into the DST gap.
Here is an example for CET time zone, where local time is set forward by one
hour at 2016-03-27T02:00:00+01:00 to 2016-03-27T03:00:00.000+02:00:
The date 2016-03-27T03:01:00.000+02:00 (1459040460000) which is just after the
DST change is first converted to local time (1459047660000). If we then apply
interval rounding for a 14m interval in local time, this takes us to
1459047240000, which unfortunately falls into the DST gap. When converting
this back to UTC, joda provides options to throw exceptions on illegal dates
like this, or correct this by adjusting the date to the new time zone offset.
We currently do the later, but this leads to converting this illegal date back
to 2016-03-27T03:54:00.000+02:00 (1459043640000), giving us a date that is
larger than the original date we wanted to round.
This change fixes this by using the "strict" option of 'convertLocalToUTC()'
to detect rounded dates that fall into the DST gap. If this happens, we can use
the time of the DST change instead as the interval start.
Even before this change, intervals around DST shifts like this can be shorter
than the desired interval. This, for example, happens when the requested
interval width doesn't completely fit into the remaining time span when the DST
shift happens. For example, using a 14m interval in UTC+1 (CET before DST
starts) leads to the following valid rounding values around the time where DST
happens:
2016-03-27T01:30:00+01:00
2016-03-27T01:44:00+01:00
2016-03-27T01:58:00+01:00
2016-03-27T02:12:00+01:00
2016-03-27T02:26:00+01:00
...
while the rounding values in UTC+2 (CET after DST start) are placed like this
around the same time:
2016-03-27T02:40:00+02:00
2016-03-27T02:54:00+02:00
2016-03-27T03:08:00+02:00
2016-03-27T03:22:00+02:00
...
From this we can see then when we switch from UTC+1 to UTC+2 at 02:00 the last
rounding value in UTC+1 is at 01:58 and the first valid one in UTC+2 is at
03:08, so even if we decide to put all the dates in between into one rounding
interval, it will only cover 10 minutes. With this change we choose to use the
moment of DST shift as an aditional interval separator, leaving us with a 2min
interval from [01:58,02:00) before the shift and an 8min interval from
[03:00,03:08) after the shift.
This change also adds tests for the above example and adds randomization to the
existing TimeIntervalRounding tests.
Adds `/regex/` as a regex constructor. A couple of fun points:
1. This makes generic the idea of arbitrary stuff adding a constant.
Both SFunction and LRegex create a statically initialized constant.
Both go through Locals to do this because they LRegex isn't directly
iterable from SScript.
2. Differentiating `/` as-in-division from `/` as-in-start-of-regex
is hard. See:
http://www-archive.mozilla.org/js/language/js20-2002-04/rationale/syntax.html#regular-expressions
The javascript folks have a way, way tougher time of it then we do
because they have semicolon insertion. We have the much simpler
delimiter rules. Even with our simpler life we still have to add
a hack to get lexing `/regex/` to work properly. I chose to add
token-level lookbehind because it seems to be a pretty contained hack.
I considered and rejected lexer modes, a lexer member variable,
having the parser set variables on the lexer (this is a fairly common
solution for js, I believe), and moving regex parsing to the parser
level.
3. I've only added a very small subset of java.util.regex to the
whitelist because it is the subset I needed to test LRegex sanely.
More deserves to be added, and maybe more regex syntax like `=~` and
`==~`. Those can probably be added without too much pain.
By default the number of searches msearch executes is capped by the number of
nodes multiplied with the default size of the search threadpool. This default can be
overwritten by using the newly added `max_concurrent_searches` parameter.
Before the msearch api would concurrently execute all searches concurrently. If many large
msearch requests would be executed this could lead to some searches being rejected
while other searches in the msearch request would succeed.
The goal of this change is to avoid this exhausting of the search TP.
Closes#17926
Add `}` is statement delimiter but only in places where it is
otherwise a valid part of the syntax, specificall the end of a block.
We do this by matching but not consuming it. Antlr 4 doesn't have
syntax for this so we have to kind of hack it together by actually
matching the `}` and then seeking backwards in the token stream to
"unmatch" it. This looks reasonably efficient. Not perfect, but way
better than the alternatives.
I tried and rejected a few options:
1. Actually consuming the `}` and piping a boolean all through the
grammar from the last statement in a block to the delimiter. This
ended up being a rather large change and made the grammar way more
complicated.
2. Adding a semantic predicate to delimiter that just does the
lookahead. This doesn't work out well because it doesn't work (I
never figured out why) and because it generates an *amazing*
`adaptivePredict` which makes a super huge DFA. It looks super
inefficient.
Closes#18821
Writeable is better for immutable objects like TimeValue.
Switch to writeZLong which takes up less space than the original
writeLong in the majority of cases. Since we expect negative
TimeValues we shouldn't use
writeVLong.
Christoph Büscher
Clinton Gormley
Vladimir Kovpak
Itamar Syn-Hershko
Robert Muir
Robert Muir
Boaz Leskes
Nik Everett
Martijn van Groningen
Aaron Mildenstein
Ryan Ernst
eratio08
Jason Tedor
Simon Willnauer
Uwe Schindler
Jack Conradson