Can the time to live (TTL) for a memcached key be set to infinite?

Question

I have implemented memcache in my PHP-MySQL based app and it gets updated regularly from a backend process.

Due to this some data is conflicting with the expiration time and other backend processes, so I came up with a solution but for that I would have to make the TTL = infinite.

score 25 · Accepted Answer · answered May 17 '11 at 07:23

25

Easy - just write 0 there.

expire

Expiration time of the item. If it's equal to zero, the item will never expire. You can also use Unix timestamp or a number of seconds starting from current time, but in the latter case the number of seconds may not exceed 2592000 (30 days).

answered May 17 '11 at 07:23

OZ_

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If it's 0, the item never expires (but memcached server doesn't guarantee this item to be stored all the time, it could be deleted from the cache to make place for other items). – ns15 Oct 03 '22 at 12:35

score 7 · Answer 2 · edited May 23 '17 at 12:10

7

You can set the TTL to 0, which means that it should 'never' expire.

But remember that it will never really be infinite. The data is stored in memory and will be lost under some circumstances, the most obvious being the server being rebooted. :)

You should always have the possibility to reconstruct that data when the memcache fails.

More details to be found here.

edited May 23 '17 at 12:10

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answered May 17 '11 at 07:22

GolezTrol

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So according to you the format will be set('key',$value,0); ?? Is it? – Himanshu May 17 '11 at 12:52

score 0 · Answer 3 · edited May 23 '17 at 11:47

0

As far as I know, if you don't set a ttl, it will never expire.

However, there are replacing policies for keys, about which you can read here

edited May 23 '17 at 11:47

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answered May 17 '11 at 07:40

Tudor Constantin

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Can the time to live (TTL) for a memcached key be set to infinite?

3 Answers3