st.c: skip all deleted entries [Bug #17779]

Update the start entry skipping all already deleted entries.
Fixes performance issue of `Hash#first` in a certain case.
This commit is contained in:
tompng (tomoya ishida) 2021-04-11 19:04:31 +09:00 committed by Nobuyoshi Nakada
parent 60bdf03b6d
commit 9f9045123e
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2 changed files with 18 additions and 2 deletions

9
st.c
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@ -1244,8 +1244,13 @@ update_range_for_deleted(st_table *tab, st_index_t n)
{
/* Do not update entries_bound here. Otherwise, we can fill all
bins by deleted entry value before rebuilding the table. */
if (tab->entries_start == n)
tab->entries_start = n + 1;
if (tab->entries_start == n) {
st_index_t start = n + 1;
st_index_t bound = tab->entries_bound;
st_table_entry *entries = tab->entries;
while (start < bound && DELETED_ENTRY_P(&entries[start])) start++;
tab->entries_start = start;
}
}
/* Delete entry with KEY from table TAB, set up *VALUE (unless