i followed example but it doesn't accept, always say there is error parse near
TIMESTAMP, pls. help me and tell me what the problem is.
I did:
INSERT INTO items VALUES(......,CURRENT TIMESTAMP,...);
The attribute has been set to be TIMESTAMP when i created this table.
Why I can't insert CURRENT TIMESTAMP?
有懂bigtable ,hbase，c*的么？问一个timestamp的问题
bigtable里面timestamp的用法在hbase,c*里有么？
比如:by specifiying timestamp, I can get value of latest version that is
earlier than a specified timestamp.
C*每个column 有个timestamp, read return 的时候，如果cl >1,会比较timestamp of
the column from different node, in case of inconsistency, return the column
with the latest timestamp. client doesn't need to deal with the vector clock
crap. the last write wins.
好吧，我没讲清楚：C* in case of inconsistency, return the column with the
latest timestamp
C*自己解决inconsistency就是假设每个record的timestamp是sync的，这不是我应用需
要到ms精确度。
App cluster来做timestamp。你在app cluster里面怎么做同步？
I think you want me to use strptime(). and I can now get the timestamp by
using
strptime("18 Oct 2008 14:11:00", "%d %b %Y %H:%M:%S", &tm).
but how do I convert GMT time "18 Oct 2008 14:11:00 GMT"to my local
timestamp, no matter where my local computer locates?
In most of cases, C* generates timestamp at server side for you. Make sure
your NTP is setup correctly which is a prerequisite for C* cluster
It's not advisable to generate timestamp at client side and pass it in with
your request.
suppose the I get a http response with header:
"Expires: Mon, 26 Jul 2009 05:00:00 GMT", I need to converts it to timestamp
of the computer's current time?
Thanks.
Timestamp can be marked on your application cluster. If you are doing mult-
DC and you are sensitive to ms order difference, you are probably doing it
wrong to begin with. i.e. You shouldn't do multi-DC for stock exchange.
这个不奇怪啊。
你可以看一看那个procedure, 你看里面有几个对temp table 的改变， 这些数据的改
变都会触发
recompilation。
我这个版本是2008 SP2的。
create procedure sys.sp_replmonitorrefreshagentdata
as
begin
set nocount on
declare @retcode int
,@agent_id int
,@agent_id2 int
,@publisher_id int
,@xact_seqno varbinary(16)
,@logreader_latency int
,@publisher_db sysname
,@publication sysname
how to find all sub directories, where the target file lives, but no deepper
level?
for example, we have timestamp files for each directory, but we don't want
to find subfolder timestamp files any more. the files look like this
/usr/local/timestamp
/usr/local/bin/timestamp
/usr/local/lib/timestamp
/usr/name/timestamp
/media/v1/
/home/jk/
now we run a find command: find ???? timestamp
we get two files
/usr/local/timestamp
/usr/name/timestamp
all deeper level timestamps are not shown.
how to do th... 阅读全帖
先声明：我没有站边, either pump or dump btc. 只是读到了自己觉得不错的文章，
分享过来，想听听大牛怎么说。
链接在此：https://blog.chain.com/a-letter-to-jamie-dimon-de89d417cb80?from=
singlemessage&isappinstalled=0
原文很长。总结如下。
Cryptocurrencies (which I prefer to call crypto assets) are a new asset
class that enable decentralized applications
Decentralized applications enable services we already have today, like
payments, storage, or computing, but without a central operator of those
services
This software model is useful to people who need c... 阅读全帖
that does not work. we don't want to discard all path including timestamp
we want to have a subset of path which include timestamp.
The subset are the parent level of timestamp folders. if any timestamp file
is in a subfolder, the subfolder will be discarded in the results.
for example:
/parent/timestamp
/parent/children/timestamp
we want to have only /parent/timestamp in results.
thanks.
作T检验，只需要三个统计量嘛，N,MEAN,STD
先求summarized statistics，再用BY-processing。跑得时间不见得少，不过至少不会
崩溃。而且这个用BY-PROCESSING可以很容易并行，最后合并结果也很容易。
134
135
136 options fullstimer;
137 data class;
138 set sashelp.class;
139 array col{20000};
140 do j=1 to dim(col); col[j]=rannor(0); end;
141 drop j;
142 run;
NOTE: There were 19 observations read from the data set SASHELP.CLASS.
NOTE: The data set WORK.CLASS has 19 observations and 20005 variables.
NOTE: DATA statement used (Total process time):... 阅读全帖
If the data is stored in a database, can't you do a SQL?
a1: current timestamp
a2: previous record within 10 mins window
SELECT a1.user_id, a1.TimeStamp as TimeStamp, SUM(a2.Activity_Count) as
visits_in_10mins
FROM activities a1
INNER JOIN activities a2
ON a1.TimeStamp BETWEEN a2.TimeStamp AND a2.TimeStamp + 10/(24*60)
AND a1.user_id = a2.user_id
GROUP BY a1.TimeStamp,a1.user_id
HAVING SUM(a2.Activity_Count) >= 500;
seems similar to LRU cache
maintain a hashmap and listnode<{business_name, timestamp[]}, count =
timestamp.count>
at every refresh:
1. add or insert new node to a node in timestamp[] from message stream
2. traverse each node to remove timestamp of 10 mins ago (timestamp is a
sorted array)
3. on event of adding/inserting/removing timestamp, move node to sorted
position.
Plus: use ReaderWriter to make sure thread safe
4. delay data--I am not sure if IB is in the club of deliberately delaying
data with import data release time. I traded /6E with TDA during NFP. it was
terrible. Graph, quote, level 2, and time&sale were off sync, all of them
delayed by seconds if not minutes. I haven't tested IB during NFP or ECB
press conference(there is one tmr morning).
My guess it is slightly better than most other retail brokers.
By the way, I wonder if anyone here knows how to test latency, eg, read msg
latency, and send ... 阅读全帖
4. delay data--I am not sure if IB is in the club of deliberately delaying
data with import data release time. I traded /6E with TDA during NFP. it was
terrible. Graph, quote, level 2, and time&sale were off sync, all of them
delayed by seconds if not minutes. I haven't tested IB during NFP or ECB
press conference(there is one tmr morning).
My guess it is slightly better than most other retail brokers.
By the way, I wonder if anyone here knows how to test latency, eg, read msg
latency, and send ... 阅读全帖
Just came across a strange problem recently.
After a re-installation of my XP system on my Dell notebook, I found that if
I change a file's content(without changing the filename), the last modified
timestamp of the folder containing that file is not changed to reflect the
file's change on its timestamp.
Yet, before my re-installation, the folder's last modified timestamp always
reflects the latest change of last modified timestamp of the files contained
in it.
I am using MultiGo to edit the sgf ... 阅读全帖
这么一个例子：
IF OBJECT_ID('T1') IS NOT NULL
DROP TABLE T1;
GO
CREATE TABLE T1 (id int PRIMARY KEY, timestamp);
GO
INSERT INTO T1(id) VALUES (1);
GO
declare @v timestamp;
INSERT INTO T1(id) OUTPUT inserted.timestamp as v VALUES (10);
select @v
假设这个@v是俺想作为stored-procedure的OUT参数返回，怎样才能把inserted.
timestamp值传递给@v呢？
多谢，给俺解决问题的奉上双黄包一个...
小弟不小心在几个表里deleted some rows in oracle, 试了试flashback, 还是解不了
问题，求高人指点。
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
昨天 //SQL> delete from plus_purl_request where id_of_job = 'CBG100049';
今天//SQL> select * from plus_purl_request where id_of_job = 'CBG100049';
no rows selected
SQL> alter table plus_purl_request enable row movement;
Table altered.
SQL> FLASHBACK TABLE plus_purl_request TO TIMESTAMP TO_TIMESTAMP('04/09... 阅读全帖
I have a client that querys server every 1 hour. It stores local cache for
the stuff it downloaded from
server. The client local cache carries a timestamp, called client_time_stamp
. Everytime the client querys
the server, the server compares the client timestamp with a server timestamp
about the data the client
needs. If the data has not changed, the server timestamp will be older than
the cache_time_stamp, thus
the server will just return cache_valid, and client preserves old client_
time_stam
