diff options
Diffstat (limited to 'src/backend/tcop/postgres.c')
| -rw-r--r-- | src/backend/tcop/postgres.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c index 0a6f80963bd..23661ae15f5 100644 --- a/src/backend/tcop/postgres.c +++ b/src/backend/tcop/postgres.c @@ -1155,7 +1155,16 @@ exec_simple_query(const char *query_string) plantree_list = pg_plan_queries(querytree_list, CURSOR_OPT_PARALLEL_OK, NULL); - /* Done with the snapshot used for parsing/planning */ + /* + * Done with the snapshot used for parsing/planning. + * + * While it looks promising to reuse the same snapshot for query + * execution (at least for simple protocol), unfortunately it causes + * execution to use a snapshot that has been acquired before locking + * any of the tables mentioned in the query. This creates user- + * visible anomalies, so refrain. Refer to + * https://postgr.es/m/flat/5075D8DF.6050500@fuzzy.cz for details. + */ if (snapshot_set) PopActiveSnapshot(); |