memflush¶
DESCRIPTION¶
memflush resets the contents of memcached(1) servers.
Warning
This means that all data in the specified servers will be deleted.
OPTIONS¶
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--help¶ Display help.
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--version¶ Display version.
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--quiet¶ Operate quietly.
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--verbose¶ Operate more verbosely.
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--servers<list of servers>¶ Specify the list of servers as hostname[:port][,hostname[:port]...].
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--binary¶ Enable binary protocol.
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--username<username>¶ Use username for SASL authentication.
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--password<password>¶ Use password for SASL authentication.
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--expire<expiration>¶ Use expiration seconds (or a UNIX timestamp).
Note
Using an expiration time (period), all keys, which have not bean updated until expiration will cease to exist.
Quoting the memcached protocol documentation, it states:
Its effect is to invalidate all existing items immediately (by default) or after the expiration specified. After invalidation none of the items will be returned in response to a retrieval command (unless it's stored again under the same key after flush_all has invalidated the items).
The most precise definition of what flush_all does is the following: it causes all items whose update time is earlier than the time at which flush_all was set to be executed to be ignored for retrieval purposes.
The intent of flush_all with a delay, was that in a setting where you have a pool of memcached servers, and you need to flush all content, you have the option of not resetting all memcached servers at the same time (which could e.g. cause a spike in database load with all clients suddenly needing to recreate content that would otherwise have been found in the memcached daemon).