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Fix lastWrittenLsnCache eviction order #12906

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Fix lastWrittenLsnCache eviction order #12906

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21 changes: 13 additions & 8 deletions pgxn/neon/neon_lwlsncache.c
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Original file line number Diff line number Diff line change
Expand Up @@ -332,8 +332,8 @@ SetLastWrittenLSNForBlockRangeInternal(XLogRecPtr lsn,
for (i = 0; i < n_blocks; i++)
{
key.blockNum = from + i;
entry = hash_search(lastWrittenLsnCache, &key, HASH_ENTER, &found);
if (found)
entry = hash_search(lastWrittenLsnCache, &key, HASH_FIND, NULL);
if (entry != NULL)
{
if (lsn > entry->lsn)
entry->lsn = lsn;
Expand All @@ -344,8 +344,7 @@ SetLastWrittenLSNForBlockRangeInternal(XLogRecPtr lsn,
}
else
{
entry->lsn = lsn;
if (hash_get_num_entries(lastWrittenLsnCache) > LwLsnCache->lastWrittenLsnCacheSize)
if (hash_get_num_entries(lastWrittenLsnCache) >= LwLsnCache->lastWrittenLsnCacheSize)
{
/* Replace least recently used entry */
LastWrittenLsnCacheEntry* victim = dlist_container(LastWrittenLsnCacheEntry, lru_node, dlist_pop_head_node(&LwLsnCache->lastWrittenLsnLRU));
Expand All @@ -355,6 +354,10 @@ SetLastWrittenLSNForBlockRangeInternal(XLogRecPtr lsn,

hash_search(lastWrittenLsnCache, victim, HASH_REMOVE, NULL);
}

entry = hash_search(lastWrittenLsnCache, &key, HASH_ENTER, &found);
Assert(!found);
entry->lsn = lsn;
}
/* Link to the end of LRU list */
dlist_push_tail(&LwLsnCache->lastWrittenLsnLRU, &entry->lru_node);
Expand Down Expand Up @@ -429,8 +432,8 @@ neon_set_lwlsn_block_v(const XLogRecPtr *lsns, NRelFileInfo relfilenode,

Assert(lsn >= WalSegMinSize);
key.blockNum = blockno + i;
entry = hash_search(lastWrittenLsnCache, &key, HASH_ENTER, &found);
if (found)
entry = hash_search(lastWrittenLsnCache, &key, HASH_FIND, NULL);
if (entry != NULL)
{
if (lsn > entry->lsn)
entry->lsn = lsn;
Expand All @@ -441,8 +444,7 @@ neon_set_lwlsn_block_v(const XLogRecPtr *lsns, NRelFileInfo relfilenode,
}
else
{
entry->lsn = lsn;
if (hash_get_num_entries(lastWrittenLsnCache) > LwLsnCache->lastWrittenLsnCacheSize)
if (hash_get_num_entries(lastWrittenLsnCache) >= LwLsnCache->lastWrittenLsnCacheSize)
{
/* Replace least recently used entry */
LastWrittenLsnCacheEntry* victim = dlist_container(LastWrittenLsnCacheEntry, lru_node, dlist_pop_head_node(&LwLsnCache->lastWrittenLsnLRU));
Expand All @@ -452,6 +454,9 @@ neon_set_lwlsn_block_v(const XLogRecPtr *lsns, NRelFileInfo relfilenode,

hash_search(lastWrittenLsnCache, victim, HASH_REMOVE, NULL);
}
entry = hash_search(lastWrittenLsnCache, &key, HASH_ENTER, &found);
Assert(!found);
entry->lsn = lsn;
}
/* Link to the end of LRU list */
dlist_push_tail(&LwLsnCache->lastWrittenLsnLRU, &entry->lru_node);
Expand Down