From 697d5aa28add566198bd1bccce5625bc35e1ea5a Mon Sep 17 00:00:00 2001 From: alterego655 <824662526@qq.com> Date: Sun, 2 Nov 2025 11:56:53 +0800 Subject: [PATCH v20 1/3] Add pairingheap_initialize() for shared memory usage The existing pairingheap_allocate() uses palloc(), which allocates from process-local memory. For shared memory use cases, the pairingheap structure must be allocated via ShmemAlloc() or embedded in a shared memory struct. Add pairingheap_initialize() to initialize an already- allocated pairingheap structure in-place, enabling shared memory usage. Discussion: https://www.postgresql.org/message-id/flat/CAPpHfdsjtZLVzxjGT8rJHCYbM0D5dwkO+BBjcirozJ6nYbOW8Q@mail.gmail.com Discussion: https://www.postgresql.org/message-id/flat/CABPTF7UNft368x-RgOXkfj475OwEbp%2BVVO-wEXz7StgjD_%3D6sw%40mail.gmail.com Author: Kartyshov Ivan Author: Alexander Korotkov Reviewed-by: Michael Paquier Reviewed-by: Peter Eisentraut Reviewed-by: Dilip Kumar Reviewed-by: Amit Kapila Reviewed-by: Alexander Lakhin Reviewed-by: Bharath Rupireddy Reviewed-by: Euler Taveira Reviewed-by: Heikki Linnakangas Reviewed-by: Kyotaro Horiguchi Reviewed-by: Xuneng Zhou --- src/backend/lib/pairingheap.c | 18 ++++++++++++++++-- src/include/lib/pairingheap.h | 3 +++ 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/src/backend/lib/pairingheap.c b/src/backend/lib/pairingheap.c index 0aef8a88f1b..fa8431f7946 100644 --- a/src/backend/lib/pairingheap.c +++ b/src/backend/lib/pairingheap.c @@ -44,12 +44,26 @@ pairingheap_allocate(pairingheap_comparator compare, void *arg) pairingheap *heap; heap = (pairingheap *) palloc(sizeof(pairingheap)); + pairingheap_initialize(heap, compare, arg); + + return heap; +} + +/* + * pairingheap_initialize + * + * Same as pairingheap_allocate(), but initializes the pairing heap in-place + * rather than allocating a new chunk of memory. Useful to store the pairing + * heap in a shared memory. + */ +void +pairingheap_initialize(pairingheap *heap, pairingheap_comparator compare, + void *arg) +{ heap->ph_compare = compare; heap->ph_arg = arg; heap->ph_root = NULL; - - return heap; } /* diff --git a/src/include/lib/pairingheap.h b/src/include/lib/pairingheap.h index 3c57d3fda1b..567586f2ecf 100644 --- a/src/include/lib/pairingheap.h +++ b/src/include/lib/pairingheap.h @@ -77,6 +77,9 @@ typedef struct pairingheap extern pairingheap *pairingheap_allocate(pairingheap_comparator compare, void *arg); +extern void pairingheap_initialize(pairingheap *heap, + pairingheap_comparator compare, + void *arg); extern void pairingheap_free(pairingheap *heap); extern void pairingheap_add(pairingheap *heap, pairingheap_node *node); extern pairingheap_node *pairingheap_first(pairingheap *heap); -- 2.39.5 (Apple Git-154)