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The expression (len_diff * 10 * (an + 1)) used as the return value of ltree_compare() is computed at int32 width. With LTREE_MAX_LEVELS = 65535, the product can exceed INT32_MAX once an ltree has more than ~14,653 levels, which causes the result to wrap and invert its sign. That corrupts btree ordering as well as the "magnitude" consumed by ltree_penalty() for GiST page splits. To fix, split ltree_compare() into two functions. The new ltree_compare_distance() function returns a float, which won't overflow. It's used by the ltree_penalty() caller. All the other callers only care about the sign of the return value, i.e. which of the arguments is greater, so change ltree_compare() to not multiply the result with (10 * (an + 1)), which avoids the overflow for those callers. Existing btree or GiST indexes on ltree columns containing values with more than ~14,653 levels may be corrupt and should be REINDEXed. Add a regression test based on the reporter's PoC. Author: Ayush Tiwari <ayushtiwari.slg01@gmail.com> Reported-by: 王跃林 <violin0613@tju.edu.cn> Discussion: https://www.postgresql.org/message-id/AI6AnABgKW93Qbx1jVzi84r9.8.1781322625756.Hmail.3020001251%40tju.edu.cn Backpatch-through: 14 |
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| .. | ||
| data | ||
| expected | ||
| sql | ||
| .gitignore | ||
| _ltree_gist.c | ||
| _ltree_op.c | ||
| crc32.c | ||
| crc32.h | ||
| lquery_op.c | ||
| ltree--1.0--1.1.sql | ||
| ltree--1.1--1.2.sql | ||
| ltree--1.1.sql | ||
| ltree.control | ||
| ltree.h | ||
| ltree_gist.c | ||
| ltree_io.c | ||
| ltree_op.c | ||
| ltreetest.sql | ||
| ltxtquery_io.c | ||
| ltxtquery_op.c | ||
| Makefile | ||