On Wed, Dec 23, 2020 at 6:01 PM Michael Paquier <mich...@paquier.xyz> wrote: > On Tue, Dec 22, 2020 at 03:12:15PM +0530, Bharath Rupireddy wrote: > > On Tue, Dec 22, 2020 at 2:07 PM Michael Paquier <mich...@paquier.xyz> wrote: > >> Note: I'd like to think that we could choose a better name for > >> CheckRelExistenceInCTAS(). > > > > I changed it to IsCTASRelCreationAllowed() and attached a v5 patch. > > Please let me know if this is okay. > > After thinking about that, using "CTAS" while other routines in the > same area use "CreateTableAs" looks inconsistent to me. So I have > come up with CreateTableAsRelExists() as name.
I think CreateTableAsRelExists() can return true if the relation already exists and false otherwise, to keep in sync with the function name. I updated this and attached v7 patch. > As the same time, I have looked at the git history to note 9bd27b7 > where we had better not give an empty output for non-text formats. So > I'd like to think that it makes sense to use ExplainDummyGroup() if > the relation exists with IF NOT EXISTS, keeping some consistency. > > What do you think? +1. Shall we add some test cases(with xml, yaml, json formats as is currently being done in explain.sql) to cover that? We can have the explain_filter() function to remove the unstable parts in the output, it looks something like below. If yes, please let me know I can add them to matview and select_into. postgres=# select explain_filter('explain(analyze, format xml) create table if not exists t1 as select 1;'); NOTICE: relation "t1" already exists, skipping explain_filter ------------------------------------------------------- <explain xmlns="http://www.postgresql.org/N/explain">+ <CREATE-TABLE-AS /> + </explain> (1 row) postgres=# select explain_filter('explain(analyze, format yaml) create table if not exists t1 as select 1;'); NOTICE: relation "t1" already exists, skipping explain_filter --------------------- - "CREATE TABLE AS" (1 row) postgres=# select explain_filter('explain(analyze, format json) create table if not exists t1 as select 1;'); NOTICE: relation "t1" already exists, skipping explain_filter --------------------- [ + "CREATE TABLE AS"+ ] (1 row) With Regards, Bharath Rupireddy. EnterpriseDB: http://www.enterprisedb.com
v7-0001-Fail-Fast-In-CTAS-CMV-If-Relation-Already-Exists.patch
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