diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/access/common/tidstore.c | 107 |
1 files changed, 82 insertions, 25 deletions
diff --git a/src/backend/access/common/tidstore.c b/src/backend/access/common/tidstore.c index f79141590ed..e1a7e824690 100644 --- a/src/backend/access/common/tidstore.c +++ b/src/backend/access/common/tidstore.c @@ -7,9 +7,9 @@ * Internally it uses a radix tree as the storage for TIDs. The key is the * BlockNumber and the value is a bitmap of offsets, BlocktableEntry. * - * TidStore can be shared among parallel worker processes by passing DSA area - * to TidStoreCreate(). Other backends can attach to the shared TidStore by - * TidStoreAttach(). + * TidStore can be shared among parallel worker processes by using + * TidStoreCreateShared(). Other backends can attach to the shared TidStore + * by TidStoreAttach(). * * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California @@ -111,15 +111,16 @@ static void tidstore_iter_extract_tids(TidStoreIter *iter, BlockNumber blkno, /* * Create a TidStore. The TidStore will live in the memory context that is * CurrentMemoryContext at the time of this call. The TID storage, backed - * by a radix tree, will live in its child memory context, rt_context. The - * TidStore will be limited to (approximately) max_bytes total memory - * consumption. If the 'area' is non-NULL, the radix tree is created in the - * DSA area. + * by a radix tree, will live in its child memory context, rt_context. * - * The returned object is allocated in backend-local memory. + * "max_bytes" is not an internally-enforced limit; it is used only as a + * hint to cap the memory block size of the memory context for TID storage. + * This reduces space wastage due to over-allocation. If the caller wants to + * monitor memory usage, it must compare its limit with the value reported + * by TidStoreMemoryUsage(). */ TidStore * -TidStoreCreate(size_t max_bytes, dsa_area *area, int tranche_id) +TidStoreCreateLocal(size_t max_bytes) { TidStore *ts; size_t initBlockSize = ALLOCSET_DEFAULT_INITSIZE; @@ -143,33 +144,74 @@ TidStoreCreate(size_t max_bytes, dsa_area *area, int tranche_id) initBlockSize, maxBlockSize); - if (area != NULL) - { - ts->tree.shared = shared_ts_create(ts->rt_context, area, - tranche_id); - ts->area = area; - } - else - ts->tree.local = local_ts_create(ts->rt_context); + ts->tree.local = local_ts_create(ts->rt_context); return ts; } /* - * Attach to the shared TidStore using the given handle. The returned object - * is allocated in backend-local memory using the CurrentMemoryContext. + * Similar to TidStoreCreateLocal() but create a shared TidStore on a + * DSA area. The TID storage will live in the DSA area, and the memory + * context rt_context will have only meta data of the radix tree. + * + * The returned object is allocated in backend-local memory. */ TidStore * -TidStoreAttach(dsa_area *area, dsa_pointer handle) +TidStoreCreateShared(size_t max_bytes, int tranche_id) { TidStore *ts; + dsa_area *area; + size_t dsa_init_size = DSA_DEFAULT_INIT_SEGMENT_SIZE; + size_t dsa_max_size = DSA_MAX_SEGMENT_SIZE; - Assert(area != NULL); + ts = palloc0(sizeof(TidStore)); + ts->context = CurrentMemoryContext; + + ts->rt_context = AllocSetContextCreate(CurrentMemoryContext, + "TID storage meta data", + ALLOCSET_SMALL_SIZES); + + /* + * Choose the initial and maximum DSA segment sizes to be no longer than + * 1/8 of max_bytes. + */ + while (8 * dsa_max_size > max_bytes) + dsa_max_size >>= 1; + + if (dsa_max_size < DSA_MIN_SEGMENT_SIZE) + dsa_max_size = DSA_MIN_SEGMENT_SIZE; + + if (dsa_init_size > dsa_max_size) + dsa_init_size = dsa_max_size; + + area = dsa_create_ext(tranche_id, dsa_init_size, dsa_max_size); + ts->tree.shared = shared_ts_create(ts->rt_context, area, + tranche_id); + ts->area = area; + + return ts; +} + +/* + * Attach to the shared TidStore. 'area_handle' is the DSA handle where + * the TidStore is created. 'handle' is the dsa_pointer returned by + * TidStoreGetHandle(). The returned object is allocated in backend-local + * memory using the CurrentMemoryContext. + */ +TidStore * +TidStoreAttach(dsa_handle area_handle, dsa_pointer handle) +{ + TidStore *ts; + dsa_area *area; + + Assert(area_handle != DSA_HANDLE_INVALID); Assert(DsaPointerIsValid(handle)); /* create per-backend state */ ts = palloc0(sizeof(TidStore)); + area = dsa_attach(area_handle); + /* Find the shared the shared radix tree */ ts->tree.shared = shared_ts_attach(area, handle); ts->area = area; @@ -178,10 +220,8 @@ TidStoreAttach(dsa_area *area, dsa_pointer handle) } /* - * Detach from a TidStore. This detaches from radix tree and frees the - * backend-local resources. The radix tree will continue to exist until - * it is either explicitly destroyed, or the area that backs it is returned - * to the operating system. + * Detach from a TidStore. This also detaches from radix tree and frees + * the backend-local resources. */ void TidStoreDetach(TidStore *ts) @@ -189,6 +229,8 @@ TidStoreDetach(TidStore *ts) Assert(TidStoreIsShared(ts)); shared_ts_detach(ts->tree.shared); + dsa_detach(ts->area); + pfree(ts); } @@ -234,7 +276,11 @@ TidStoreDestroy(TidStore *ts) { /* Destroy underlying radix tree */ if (TidStoreIsShared(ts)) + { shared_ts_free(ts->tree.shared); + + dsa_detach(ts->area); + } else local_ts_free(ts->tree.local); @@ -420,6 +466,17 @@ TidStoreMemoryUsage(TidStore *ts) return local_ts_memory_usage(ts->tree.local); } +/* + * Return the DSA area where the TidStore lives. + */ +dsa_area * +TidStoreGetDSA(TidStore *ts) +{ + Assert(TidStoreIsShared(ts)); + + return ts->area; +} + dsa_pointer TidStoreGetHandle(TidStore *ts) { |