From 4bea91f21f61d01bd40a4191a4a8c82d0959fffe Mon Sep 17 00:00:00 2001 From: Masahiko Sawada Date: Mon, 20 Oct 2025 10:38:52 -0700 Subject: Support COPY TO for partitioned tables. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Previously, COPY TO command didn't support directly specifying partitioned tables so users had to use COPY (SELECT ...) TO variant. This commit adds direct COPY TO support for partitioned tables, improving both usability and performance. Performance tests show it's faster than the COPY (SELECT ...) TO variant as it avoids the overheads of query processing and sending results to the COPY TO command. When used with partitioned tables, COPY TO copies the same rows as SELECT * FROM table. Row-level security policies of the partitioned table are applied in the same way as when executing COPY TO on a plain table. Author: jian he Reviewed-by: vignesh C Reviewed-by: David Rowley Reviewed-by: Melih Mutlu Reviewed-by: Kirill Reshke Reviewed-by: Atsushi Torikoshi Reviewed-by: Álvaro Herrera Reviewed-by: Masahiko Sawada Reviewed-by: Chao Li Discussion: https://postgr.es/m/CACJufxEZt%2BG19Ors3bQUq-42-61__C%3Dy5k2wk%3DsHEFRusu7%3DiQ%40mail.gmail.com --- src/backend/commands/copy.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'src/backend/commands/copy.c') diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c index fae9c41db65..44020d0ae80 100644 --- a/src/backend/commands/copy.c +++ b/src/backend/commands/copy.c @@ -251,11 +251,15 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt, * relation which we have opened and locked. Use "ONLY" so that * COPY retrieves rows from only the target table not any * inheritance children, the same as when RLS doesn't apply. + * + * However, when copying data from a partitioned table, we don't + * use "ONLY", since we need to retrieve rows from its descendant + * tables too. */ from = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)), pstrdup(RelationGetRelationName(rel)), -1); - from->inh = false; /* apply ONLY */ + from->inh = (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE); /* Build query */ select = makeNode(SelectStmt); -- cgit v1.2.3