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Fix LFC prewarm cancellation

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This commit is contained in:
Heikki Linnakangas
2025-08-01 00:11:50 +03:00
parent 26bd994852
commit 4a031b9467
2 changed files with 118 additions and 97 deletions
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19
pgxn/neon/communicator_new.c
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@@ -423,11 +423,20 @@ communicator_new_get_lfc_state(size_t max_entries)
struct FileCacheIterator iter;
FileCacheState *fcs;
uint8 *bitmap;
uint64_t num_pages_used;
size_t n_entries;
size_t state_size;
size_t n_pages;
/* TODO: Max(max_entries, <current # of entries in cache>) */
size_t n_entries = max_entries;
size_t state_size = FILE_CACHE_STATE_SIZE_FOR_CHUNKS(n_entries, 1);
size_t n_pages = 0;
/*
* Calculate the size of the returned state.
*
* FIXME: if the LFC is very large, this can exceed 1 GB, resulting in a
* palloc error.
*/
num_pages_used = bcomm_cache_get_num_pages_used(my_bs);
n_entries = Min(num_pages_used, max_entries);
state_size = FILE_CACHE_STATE_SIZE_FOR_CHUNKS(n_entries, 1);
fcs = (FileCacheState *) palloc0(state_size);
SET_VARSIZE(fcs, state_size);
@@ -437,6 +446,7 @@ communicator_new_get_lfc_state(size_t max_entries)
bitmap = FILE_CACHE_STATE_BITMAP(fcs);
bcomm_cache_iterate_begin(my_bs, &iter);
n_pages = 0;
while (n_pages < max_entries && bcomm_cache_iterate_next(my_bs, &iter))
{
BufferTag tag;
@@ -455,6 +465,7 @@ communicator_new_get_lfc_state(size_t max_entries)
BITMAP_SET(bitmap, i);
}
fcs->n_pages = n_pages;
fcs->n_chunks = n_pages;
return fcs;
}

10
pgxn/neon/lfc_prewarm.c
View File

@@ -440,6 +440,8 @@ lfc_prewarm_with_async_requests(FileCacheState *fcs)
n_entries = Min(fcs->n_chunks, lfc_prewarm_limit);
Assert(n_entries != 0);
PG_TRY();
{
LWLockAcquire(prewarm_lock, LW_EXCLUSIVE);
/* Do not prewarm more entries than LFC limit */
@@ -555,6 +557,14 @@ lfc_prewarm_with_async_requests(FileCacheState *fcs)
LWLockAcquire(prewarm_lock, LW_EXCLUSIVE);
prewarm_ctl->prewarm_active = false;
LWLockRelease(prewarm_lock);
}
PG_CATCH();
{
elog(LOG, "LFC: cancel prewarm");
prewarm_ctl->prewarm_canceled = true;
prewarm_ctl->prewarm_active = false;
}
PG_END_TRY();
}
PG_FUNCTION_INFO_V1(get_local_cache_state);