diff options
Diffstat (limited to 'src/backend/access/heap/vacuumlazy.c')
| -rw-r--r-- | src/backend/access/heap/vacuumlazy.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index 6d287b38cf5..f28326bad09 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -1225,7 +1225,12 @@ lazy_scan_heap(LVRelState *vacrel) vacrel->next_unskippable_eager_scanned = false; vacrel->next_unskippable_vmbuffer = InvalidBuffer; - /* Set up the read stream for vacuum's first pass through the heap */ + /* + * Set up the read stream for vacuum's first pass through the heap. + * + * This could be made safe for READ_STREAM_USE_BATCHING, but only with + * explicit work in heap_vac_scan_next_block. + */ stream = read_stream_begin_relation(READ_STREAM_MAINTENANCE, vacrel->bstrategy, vacrel->rel, @@ -2669,6 +2674,8 @@ lazy_vacuum_all_indexes(LVRelState *vacrel) * Read stream callback for vacuum's third phase (second pass over the heap). * Gets the next block from the TID store and returns it or InvalidBlockNumber * if there are no further blocks to vacuum. + * + * NB: Assumed to be safe to use with READ_STREAM_USE_BATCHING. */ static BlockNumber vacuum_reap_lp_read_stream_next(ReadStream *stream, @@ -2732,8 +2739,16 @@ lazy_vacuum_heap_rel(LVRelState *vacrel) iter = TidStoreBeginIterate(vacrel->dead_items); - /* Set up the read stream for vacuum's second pass through the heap */ - stream = read_stream_begin_relation(READ_STREAM_MAINTENANCE, + /* + * Set up the read stream for vacuum's second pass through the heap. + * + * It is safe to use batchmode, as vacuum_reap_lp_read_stream_next() does + * not need to wait for IO and does not perform locking. Once we support + * parallelism it should still be fine, as presumably the holder of locks + * would never be blocked by IO while holding the lock. + */ + stream = read_stream_begin_relation(READ_STREAM_MAINTENANCE | + READ_STREAM_USE_BATCHING, vacrel->bstrategy, vacrel->rel, MAIN_FORKNUM, |