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通过FastCGI Cache实现服务降级 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...，架构图如下：
Degradation
实现的关键点在于通过error_page处理异常，并且完成服务降级：
limit_conn_zone $server_name zone=perserver:1m;
error_page 500 502 503 504 = @failover;
fastcgi_cache_path
/tmp
levels=1:2
keys_zone=failover:100m
i...
Insert, on duplicate update in PostgreSQL?
...FLICT clause. with the following syntax (similar to MySQL)
INSERT INTO the_table (id, column_1, column_2)
VALUES (1, 'A', 'X'), (2, 'B', 'Y'), (3, 'C', 'Z')
ON CONFLICT (id) DO UPDATE
SET column_1 = excluded.column_1,
column_2 = excluded.column_2;
Searching postgresql's email group a...
CSS: background image on background color
...nswered Jan 15 '18 at 17:12
Risa__BRisa__B
39544 silver badges88 bronze badges
...
How can I pass a member function where a free function is expected?
...)(void*, int, int), void* context) {
fptr(context, 17, 42);
}
void non_member(void*, int i0, int i1) {
std::cout << "I don't need any context! i0=" << i0 << " i1=" << i1 << "\n";
}
struct foo {
void member(int i0, int i1) {
std::cout << "memb...
Entity Framework: One Database, Multiple DbContexts. Is this a bad idea? [closed]
...tabase tables (instead of "dbo").
More importantly it will also prefix the __MigrationHistory table(s), e.g. Customer.__MigrationHistory.
So you can have more than one __MigrationHistory table in a single database, one for each context.
So the changes you make for one context will not mess with the ...
Find where python is installed (if it isn't default dir)
...gt;>> sys.executable
'c:\\Python26\\python.exe'
>>> sys.exec_prefix
'c:\\Python26'
>>>
>>> print '\n'.join(sys.path)
c:\Python26\lib\site-packages\setuptools-0.6c11-py2.6.egg
c:\Python26\lib\site-packages\nose-1.0.0-py2.6.egg
C:\Windows\system32\python26.zip
c:\Pyth...
What are valid values for the id attribute in HTML?
...wed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").
HTML 5 is even more permissive, saying only that an id must contain at least one character and may not contain any space characters.
The id attribute is case sensitive in XHTML.
As a ...
Add list to set?
...rticle. Pythons hashing algorithms are explained on effbot.org and pythons __hash__ function in the python reference.
Some facts:
Set elements as well as dictionary keys have to be hashable
Some unhashable datatypes:
list: use tuple instead
set: use frozenset instead
dict: has no official count...
Is it possible to GROUP BY multiple columns using MySQL?
...y the rows are sorted.
In your example, you would write
GROUP BY fV.tier_id, f.form_template_id
Meanwhile, the code
GROUP BY f.form_template_id, fV.tier_id
would give similar results, but sorted differently.
share
...
Safely remove migration In Laravel
...teps:
Manually delete the migration file under app/database/migrations/my_migration_file_name.php
Reset the composer autoload files: composer dump-autoload
Relax
If you did run the migration (php artisan migrate), you may do this:
a) Run migrate:rollback - it is the right way to undo the last...