From ed9c9b033546129daf06d4aa013f5c0e22c5947d Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Mon, 30 Nov 2020 18:24:55 -0300 Subject: [PATCH] Document concurrent indexes waiting on each other Because regular CREATE INDEX commands are independent, and there's no logical data dependency, it's not immediately obvious that transactions held by concurrent index builds on one table will block the second phase of concurrent index creation on an unrelated table, so document this caveat. Backpatch this all the way back. In branch master, mention that only some indexes are involved. Author: James Coleman Reviewed-by: David Johnston Discussion: https://postgr.es/m/CAAaqYe994=PUrn8CJZ4UEo_S-FfRr_3ogERyhtdgHAb2WG_Ufg@mail.gmail.com --- doc/src/sgml/ref/create_index.sgml | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml index ad4956958f..7b3465ca7a 100644 --- a/doc/src/sgml/ref/create_index.sgml +++ b/doc/src/sgml/ref/create_index.sgml @@ -533,7 +533,8 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ [ IF NOT EXISTS ] ) predating the second - scan to terminate. Then finally the index can be marked ready for use, + scan to terminate, including transactions used by any phase of concurrent + index builds on other tables. Then finally the index can be marked ready for use, and the CREATE INDEX command terminates. Even then, however, the index may not be immediately usable for queries: in the worst case, it cannot be used as long as transactions exist that