Hey, Looks like I never updated the manpage. In the past the item size max was achieved by changing the slab page size, but that hasn't been true for a long time.
>From ./memcached -h: -m, --memory-limit=<num> item memory in megabytes (default: 64) ... -m just means the memory limit in megabytes, abstract from the page size. I think that was always true. In any recentish version, any item larger than half a page size (512k) is created by stitching page chunks together. This prevents waste when an item would be more than half a page size. Is there a problem you're trying to track down? I'll update the manpage. On Fri, 3 Jul 2020, Shweta Agrawal wrote: > Hi, > Sorry if I am repeating the question, I searched the list but could not find > definite answer. So posting it. > > Memcache version: 1.5.10 > I have started memcahce with option: -I 4m (setting maximum item size to > 4MB).Verified it is set by command stats settings , I can see STAT > item_size_max > 4194304. > > Documentation from git repository here stats that: > > -I, --max-item-size=<size> > Override the default size of each slab page. The default size is 1mb. Default > value for this parameter is 1m, minimum is 1k, max is 1G (1024 * 1024 * 1024). > Adjusting this value changes the item size limit. > My understanding from documentation is this option will allow to save items > with size till 4MB and the page size for each slab will be 4MB (as I set it as > -I 4m). > > I am able to save items till 4MB but the page-size is still 1MB. > > -m memory size is default 64MB. > > Calculation: > -> Calculated total pages used from stats slabs output parameter total_pages > = 64 (If page size is 4MB then total pages should not be more than 16. Also > when I store 8 items of ~3MB it uses 25 pages but if page size is 4MB, it > should use 8 pages right.) > > Can you please help me in understanding the behaviour? > > Attached files with details for output of command stats settings and stats > slabs. > Below is the summarized view of the distribution. > First added items with variable sizes, then then added items with 3MB and > above. > > data_distribution.png > > > > Please let me know in case more details are required or question is not clear. > > Thank You, > Shweta > > -- > > --- > You received this message because you are subscribed to the Google Groups > "memcached" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to memcached+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/memcached/2b640e1f-9f59-4432-a930-d830cbe8566do%40googlegroups.com. > > -- --- You received this message because you are subscribed to the Google Groups "memcached" group. To unsubscribe from this group and stop receiving emails from it, send an email to memcached+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/memcached/alpine.DEB.2.21.2007031149160.18887%40dskull.
