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| author | dormando <dormando@rydia.net> | 2017-11-16 18:51:44 -0800 |
|---|---|---|
| committer | dormando <dormando@rydia.net> | 2017-11-28 14:18:05 -0800 |
| commit | 46a297cb0b6bad956793c25cc04ee208fc75a843 (patch) | |
| tree | 585aeee59c1ad4a7cba82e2a44826329cdfb611d /storage.c | |
| parent | fa37474c2a98ce4f23a4c3e059d432f798b878b6 (diff) | |
| download | memcached-46a297cb0b6bad956793c25cc04ee208fc75a843.tar.gz | |
extstore: crawler fix and ext_low_ttl option
LRU crawler was not marking reclaimed expired items as removed from the
storage engine. This could cause fragmentation to persist much longer than it
should, but would not cause any problems once compaction started.
Adds "ext_low_ttl" option. Items with a remaining expiration age below this
value are grouped into special pages. If you have a mixed TTL workload this
would help prevent low TTL items from causing excess fragmentation/compaction.
Pages with low ttl items are excluded from compaction.
Diffstat (limited to 'storage.c')
| -rw-r--r-- | storage.c | 10 |
1 files changed, 8 insertions, 2 deletions
@@ -10,6 +10,7 @@ #define PAGE_BUCKET_DEFAULT 0 #define PAGE_BUCKET_COMPACT 1 #define PAGE_BUCKET_CHUNKED 2 +#define PAGE_BUCKET_LOWTTL 3 int lru_maintainer_store(void *storage, const int clsid) { //int i; @@ -25,7 +26,7 @@ int lru_maintainer_store(void *storage, const int clsid) { chunks_free = slabs_available_chunks(clsid, &mem_limit_reached, NULL, &chunks_perslab); // if we are low on chunks and no spare, push out early. - if (chunks_free < (chunks_perslab / 2) && mem_limit_reached) + if (chunks_free < chunks_perslab && mem_limit_reached) item_age = 0; it_info.it = NULL; @@ -57,6 +58,10 @@ int lru_maintainer_store(void *storage, const int clsid) { if (hdr_it != NULL) { int bucket = (it->it_flags & ITEM_CHUNKED) ? PAGE_BUCKET_CHUNKED : PAGE_BUCKET_DEFAULT; + // Compres soon to expire items into similar pages. + if (it->exptime - current_time < settings.ext_low_ttl) { + bucket = PAGE_BUCKET_LOWTTL; + } hdr_it->it_flags |= ITEM_HDR; io.len = orig_ntotal; io.mode = OBJ_IO_WRITE; @@ -156,7 +161,8 @@ static int storage_compact_check(void *storage, logger *l, // find oldest page by version that violates the constraint for (x = 0; x < st.page_count; x++) { - if (st.page_data[x].version == 0) + if (st.page_data[x].version == 0 || + st.page_data[x].bucket == PAGE_BUCKET_LOWTTL) continue; if (st.page_data[x].bytes_used < frag_limit) { if (st.page_data[x].version < low_version) { |