diff options
| -rw-r--r-- | src/backend/replication/logical/reorderbuffer.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c index 22bcf171ff0..e3a5c7b660c 100644 --- a/src/backend/replication/logical/reorderbuffer.c +++ b/src/backend/replication/logical/reorderbuffer.c @@ -337,15 +337,20 @@ ReorderBufferAllocate(void) sizeof(ReorderBufferTXN)); /* - * XXX the allocation sizes used below pre-date generation context's block - * growing code. These values should likely be benchmarked and set to - * more suitable values. + * To minimize memory fragmentation caused by long-running transactions + * with changes spanning multiple memory blocks, we use a single + * fixed-size memory block for decoded tuple storage. The performance + * testing showed that the default memory block size maintains logical + * decoding performance without causing fragmentation due to concurrent + * transactions. One might think that we can use the max size as + * SLAB_LARGE_BLOCK_SIZE but the test also showed it doesn't help resolve + * the memory fragmentation. */ buffer->tup_context = GenerationContextCreate(new_ctx, "Tuples", - SLAB_LARGE_BLOCK_SIZE, - SLAB_LARGE_BLOCK_SIZE, - SLAB_LARGE_BLOCK_SIZE); + SLAB_DEFAULT_BLOCK_SIZE, + SLAB_DEFAULT_BLOCK_SIZE, + SLAB_DEFAULT_BLOCK_SIZE); hash_ctl.keysize = sizeof(TransactionId); hash_ctl.entrysize = sizeof(ReorderBufferTXNByIdEnt); |