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authorGravatar Ziv Scully <ziv@mit.edu>2015-11-17 02:44:37 -0500
committerGravatar Ziv Scully <ziv@mit.edu>2015-11-17 02:44:37 -0500
commit39804bcf37a35ca6a2cb5e49849ce9453c9025bc (patch)
tree5678aaab6c6d9e4362b67727caec80bf39322bce
parent96537889753c222279e3937495dbc56054b377b9 (diff)
Make cache flushes happen immediately instead of at end of transaction.
-rw-r--r--src/c/urweb.c90
-rw-r--r--src/sqlcache.sml2
2 files changed, 46 insertions, 46 deletions
diff --git a/src/c/urweb.c b/src/c/urweb.c
index 6a48e95e..c1cfe94c 100644
--- a/src/c/urweb.c
+++ b/src/c/urweb.c
@@ -4585,8 +4585,10 @@ static void uw_Sqlcache_freeEntry(uw_Sqlcache_Entry* entry) {
static unsigned int uw_Sqlcache_maxSize = 1234567890;
static void uw_Sqlcache_delete(uw_Sqlcache_Cache *cache, uw_Sqlcache_Entry *entry) {
- HASH_DEL(cache->table, entry);
- uw_Sqlcache_freeEntry(entry);
+ if (entry) {
+ HASH_DEL(cache->table, entry);
+ uw_Sqlcache_freeEntry(entry);
+ }
}
static uw_Sqlcache_Entry *uw_Sqlcache_find(uw_Sqlcache_Cache *cache, char *key, size_t len, int bump) {
@@ -4723,47 +4725,6 @@ static void uw_Sqlcache_storeCommitOne(uw_Sqlcache_Cache *cache, char **keys, uw
}
static void uw_Sqlcache_flushCommitOne(uw_Sqlcache_Cache *cache, char **keys) {
- pthread_rwlock_wrlock(&cache->lockIn);
- size_t numKeys = cache->numKeys;
- if (numKeys == 0) {
- uw_Sqlcache_Entry *entry = cache->table;
- if (entry) {
- uw_Sqlcache_freeValue(entry->value);
- entry->value = NULL;
- }
- } else {
- char *key = uw_Sqlcache_allocKeyBuffer(keys, numKeys);
- char *buf = key;
- time_t timeNow = uw_Sqlcache_getTimeNow(cache);
- uw_Sqlcache_Entry *entry = NULL;
- while (numKeys-- > 0) {
- char *k = keys[numKeys];
- if (!k) {
- if (entry) {
- entry->timeInvalid = timeNow;
- } else {
- // Haven't found an entry yet, so the first key was null.
- cache->timeInvalid = timeNow;
- }
- free(key);
- pthread_rwlock_unlock(&cache->lockIn);
- return;
- }
- buf = uw_Sqlcache_keyCopy(buf, k);
- size_t len = buf - key;
- entry = uw_Sqlcache_find(cache, key, len, 0);
- if (!entry) {
- // Nothing in the cache to flush.
- free(key);
- pthread_rwlock_unlock(&cache->lockIn);
- return;
- }
- }
- free(key);
- // All the keys were non-null and the relevant entry is present, so we delete it.
- uw_Sqlcache_delete(cache, entry);
- }
- pthread_rwlock_unlock(&cache->lockIn);
}
static void uw_Sqlcache_commit(void *data) {
@@ -4853,6 +4814,45 @@ void uw_Sqlcache_store(uw_context ctx, uw_Sqlcache_Cache *cache, char **keys, uw
}
void uw_Sqlcache_flush(uw_context ctx, uw_Sqlcache_Cache *cache, char **keys) {
- // A flush is represented in the queue as storing NULL.
- uw_Sqlcache_store(ctx, cache, keys, NULL);
+ // A flush has to happen immediately so that subsequent stores in the same transaction fail.
+ // This is safe to do because we will always call [uw_Sqlcache_wlock] earlier.
+ // If the transaction fails, the only harm done is a few extra cache misses.
+ pthread_rwlock_wrlock(&cache->lockIn);
+ size_t numKeys = cache->numKeys;
+ if (numKeys == 0) {
+ uw_Sqlcache_Entry *entry = cache->table;
+ if (entry) {
+ uw_Sqlcache_freeValue(entry->value);
+ entry->value = NULL;
+ }
+ } else {
+ char *key = uw_Sqlcache_allocKeyBuffer(keys, numKeys);
+ char *buf = key;
+ time_t timeNow = uw_Sqlcache_getTimeNow(cache);
+ while (numKeys-- > 0) {
+ char *k = keys[numKeys];
+ if (!k) {
+ size_t len = buf - key;
+ if (len == 0) {
+ // The first key was null.
+ cache->timeInvalid = timeNow;
+ } else {
+ uw_Sqlcache_Entry *entry = uw_Sqlcache_find(cache, key, len, 0);
+ if (entry) {
+ entry->timeInvalid = timeNow;
+ }
+ }
+ free(key);
+ pthread_rwlock_unlock(&cache->lockIn);
+ return;
+ }
+ buf = uw_Sqlcache_keyCopy(buf, k);
+ }
+ // All the keys were non-null, so we delete the pointed-to entry.
+ size_t len = buf - key;
+ uw_Sqlcache_Entry *entry = uw_Sqlcache_find(cache, key, len, 0);
+ free(key);
+ uw_Sqlcache_delete(cache, entry);
+ }
+ pthread_rwlock_unlock(&cache->lockIn);
}
diff --git a/src/sqlcache.sml b/src/sqlcache.sml
index 481acbeb..a8ef647b 100644
--- a/src/sqlcache.sml
+++ b/src/sqlcache.sml
@@ -1,4 +1,4 @@
-structure Sqlcache (* DEBUG :> SQLCACHE *) = struct
+structure Sqlcache :> SQLCACHE = struct
(*********************)