diff options
Diffstat (limited to 'src/backend/utils/adt/formatting.c')
| -rw-r--r-- | src/backend/utils/adt/formatting.c | 70 |
1 files changed, 38 insertions, 32 deletions
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c index d158ef9adf9..4118b78ae41 100644 --- a/src/backend/utils/adt/formatting.c +++ b/src/backend/utils/adt/formatting.c @@ -3376,20 +3376,32 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out) } } +/* + * The invariant for DCH cache entry management is that DCHCounter is equal + * to the maximum age value among the existing entries, and we increment it + * whenever an access occurs. If we approach overflow, deal with that by + * halving all the age values, so that we retain a fairly accurate idea of + * which entries are oldest. + */ +static inline void +DCH_prevent_counter_overflow(void) +{ + if (DCHCounter >= (INT_MAX - 1)) + { + for (int i = 0; i < n_DCHCache; i++) + DCHCache[i]->age >>= 1; + DCHCounter >>= 1; + } +} + /* select a DCHCacheEntry to hold the given format picture */ static DCHCacheEntry * DCH_cache_getnew(const char *str) { DCHCacheEntry *ent; - /* handle counter overflow by resetting all ages */ - if (DCHCounter >= (INT_MAX - DCH_CACHE_ENTRIES)) - { - DCHCounter = 0; - - for (int i = 0; i < n_DCHCache; i++) - DCHCache[i]->age = (++DCHCounter); - } + /* Ensure we can advance DCHCounter below */ + DCH_prevent_counter_overflow(); /* * If cache is full, remove oldest entry (or recycle first not-valid one) @@ -3445,14 +3457,8 @@ DCH_cache_getnew(const char *str) static DCHCacheEntry * DCH_cache_search(const char *str) { - /* handle counter overflow by resetting all ages */ - if (DCHCounter >= (INT_MAX - DCH_CACHE_ENTRIES)) - { - DCHCounter = 0; - - for (int i = 0; i < n_DCHCache; i++) - DCHCache[i]->age = (++DCHCounter); - } + /* Ensure we can advance DCHCounter below */ + DCH_prevent_counter_overflow(); for (int i = 0; i < n_DCHCache; i++) { @@ -4057,20 +4063,26 @@ do { \ (_n)->zero_end = 0; \ } while(0) +/* This works the same as DCH_prevent_counter_overflow */ +static inline void +NUM_prevent_counter_overflow(void) +{ + if (NUMCounter >= (INT_MAX - 1)) + { + for (int i = 0; i < n_NUMCache; i++) + NUMCache[i]->age >>= 1; + NUMCounter >>= 1; + } +} + /* select a NUMCacheEntry to hold the given format picture */ static NUMCacheEntry * NUM_cache_getnew(const char *str) { NUMCacheEntry *ent; - /* handle counter overflow by resetting all ages */ - if (NUMCounter >= (INT_MAX - NUM_CACHE_ENTRIES)) - { - NUMCounter = 0; - - for (int i = 0; i < n_NUMCache; i++) - NUMCache[i]->age = (++NUMCounter); - } + /* Ensure we can advance NUMCounter below */ + NUM_prevent_counter_overflow(); /* * If cache is full, remove oldest entry (or recycle first not-valid one) @@ -4126,14 +4138,8 @@ NUM_cache_getnew(const char *str) static NUMCacheEntry * NUM_cache_search(const char *str) { - /* handle counter overflow by resetting all ages */ - if (NUMCounter >= (INT_MAX - NUM_CACHE_ENTRIES)) - { - NUMCounter = 0; - - for (int i = 0; i < n_NUMCache; i++) - NUMCache[i]->age = (++NUMCounter); - } + /* Ensure we can advance NUMCounter below */ + NUM_prevent_counter_overflow(); for (int i = 0; i < n_NUMCache; i++) { |