From 5d28c9bd73e29890cccd3f6b188b86f81031f671 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 6 Nov 2018 18:33:15 -0500 Subject: [PATCH] Disable recheck_on_update optimization to avoid crashes. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The code added by commit c203d6cf8 causes a crash in at least one case, where a potentially-optimizable expression index has a storage type different from the input data type. A cursory code review turned up numerous other problems that seem impractical to fix on short notice. Andres argued for revert of that patch some time ago, and if additional senior committers had been paying attention, that's likely what would have happened, but we were not :-( At this point we can't just revert, at least not in v11, because that would mean an ABI break for code touching relcache entries. And we should not remove the (also buggy) support for the recheck_on_update index reloption, since it might already be used in some databases in the field. So this patch just does the as-little-invasive-as-possible measure of disabling the feature as though recheck_on_update were forced off for all indexes. I also removed the related regression tests (which would otherwise fail) and the user-facing documentation of the reloption. We should undertake a more thorough code cleanup if the patch can't be fixed, but not under the extreme time pressure of being already overdue for 11.1 release. Per report from Ondřej Bouda and subsequent private discussion among pgsql-release. Discussion: https://postgr.es/m/20181106185255.776mstcyehnc63ty@alvherre.pgsql --- doc/src/sgml/ref/create_index.sgml | 37 +------------- doc/src/sgml/release-11.sgml | 13 ----- src/backend/utils/cache/relcache.c | 3 ++ src/test/regress/expected/func_index.out | 64 ------------------------ src/test/regress/parallel_schedule | 2 +- src/test/regress/serial_schedule | 1 - src/test/regress/sql/func_index.sql | 31 ------------ 7 files changed, 6 insertions(+), 145 deletions(-) delete mode 100644 src/test/regress/expected/func_index.out delete mode 100644 src/test/regress/sql/func_index.sql diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml index 4df3d756de..ad619cdcfe 100644 --- a/doc/src/sgml/ref/create_index.sgml +++ b/doc/src/sgml/ref/create_index.sgml @@ -356,41 +356,8 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ [ IF NOT EXISTS ] The optional WITH clause specifies storage parameters for the index. Each index method has its own set of allowed - storage parameters. All indexes accept the following parameter: - - - - - recheck_on_update - - - Specifies whether to recheck a functional index value to see whether - we can use a HOT update or not. The default value is on for functional - indexes with an total expression cost less than 1000, otherwise off. - You might decide to turn this off if you knew that a function used in - an index is unlikely to return the same value when one of the input - columns is updated and so the recheck is not worth the additional cost - of executing the function. - - - - Functional indexes are used frequently for the case where the function - returns a subset of the argument. Examples of this would be accessing - part of a string with SUBSTR() or accessing a single - field in a JSON document using an expression such as - (bookinfo->>'isbn'). In this example, the JSON - document might be updated frequently, yet it is uncommon for the ISBN - field for a book to change so we would keep the parameter set to on - for that index. A more frequently changing field might have an index - with this parameter turned off, while very frequently changing fields - might be better to avoid indexing at all under high load. - - - - - - - The B-tree, hash, GiST and SP-GiST index methods all accept this parameter: + storage parameters. The B-tree, hash, GiST and SP-GiST index methods all + accept this parameter: diff --git a/doc/src/sgml/release-11.sgml b/doc/src/sgml/release-11.sgml index f7ddcec120..36e69654e2 100644 --- a/doc/src/sgml/release-11.sgml +++ b/doc/src/sgml/release-11.sgml @@ -1437,19 +1437,6 @@ same commits as above - - - - - Allow heap-only-tuple (HOT) updates for - expression indexes when the values of the expressions are unchanged - (Konstantin Knizhnik) - - - - diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c index fd3d010b77..aecbd4a943 100644 --- a/src/backend/utils/cache/relcache.c +++ b/src/backend/utils/cache/relcache.c @@ -4755,6 +4755,7 @@ IsProjectionFunctionalIndex(Relation index, IndexInfo *ii) { bool is_projection = false; +#ifdef NOT_USED if (ii->ii_Expressions) { HeapTuple tuple; @@ -4800,6 +4801,8 @@ IsProjectionFunctionalIndex(Relation index, IndexInfo *ii) } ReleaseSysCache(tuple); } +#endif + return is_projection; } diff --git a/src/test/regress/expected/func_index.out b/src/test/regress/expected/func_index.out deleted file mode 100644 index 307ac97b4b..0000000000 --- a/src/test/regress/expected/func_index.out +++ /dev/null @@ -1,64 +0,0 @@ -begin; -create table keyvalue(id integer primary key, info jsonb); -create index nameindex on keyvalue((info->>'name')) with (recheck_on_update=false); -insert into keyvalue values (1, '{"name": "john", "data": "some data"}'); -update keyvalue set info='{"name": "john", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); - pg_stat_get_xact_tuples_hot_updated -------------------------------------- - 0 -(1 row) - -rollback; -begin; -create table keyvalue(id integer primary key, info jsonb); -create index nameindex on keyvalue((info->>'name')) with (recheck_on_update=true); -insert into keyvalue values (1, '{"name": "john", "data": "some data"}'); -update keyvalue set info='{"name": "john", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); - pg_stat_get_xact_tuples_hot_updated -------------------------------------- - 1 -(1 row) - -update keyvalue set info='{"name": "smith", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); - pg_stat_get_xact_tuples_hot_updated -------------------------------------- - 1 -(1 row) - -update keyvalue set info='{"name": "smith", "data": "some more data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); - pg_stat_get_xact_tuples_hot_updated -------------------------------------- - 2 -(1 row) - -rollback; -begin; -create table keyvalue(id integer primary key, info jsonb); -create index nameindex on keyvalue((info->>'name')); -insert into keyvalue values (1, '{"name": "john", "data": "some data"}'); -update keyvalue set info='{"name": "john", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); - pg_stat_get_xact_tuples_hot_updated -------------------------------------- - 1 -(1 row) - -update keyvalue set info='{"name": "smith", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); - pg_stat_get_xact_tuples_hot_updated -------------------------------------- - 1 -(1 row) - -update keyvalue set info='{"name": "smith", "data": "some more data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); - pg_stat_get_xact_tuples_hot_updated -------------------------------------- - 2 -(1 row) - -rollback; diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule index b5e15501dd..289c658483 100644 --- a/src/test/regress/parallel_schedule +++ b/src/test/regress/parallel_schedule @@ -84,7 +84,7 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi # ---------- # Another group of parallel tests # ---------- -test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password func_index +test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password # ---------- # Another group of parallel tests diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule index 49329ffbb6..bc43b18c62 100644 --- a/src/test/regress/serial_schedule +++ b/src/test/regress/serial_schedule @@ -99,7 +99,6 @@ test: portals test: arrays test: btree_index test: hash_index -test: func_index test: update test: delete test: namespace diff --git a/src/test/regress/sql/func_index.sql b/src/test/regress/sql/func_index.sql deleted file mode 100644 index c267c93eb0..0000000000 --- a/src/test/regress/sql/func_index.sql +++ /dev/null @@ -1,31 +0,0 @@ -begin; -create table keyvalue(id integer primary key, info jsonb); -create index nameindex on keyvalue((info->>'name')) with (recheck_on_update=false); -insert into keyvalue values (1, '{"name": "john", "data": "some data"}'); -update keyvalue set info='{"name": "john", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); -rollback; - -begin; -create table keyvalue(id integer primary key, info jsonb); -create index nameindex on keyvalue((info->>'name')) with (recheck_on_update=true); -insert into keyvalue values (1, '{"name": "john", "data": "some data"}'); -update keyvalue set info='{"name": "john", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); -update keyvalue set info='{"name": "smith", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); -update keyvalue set info='{"name": "smith", "data": "some more data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); -rollback; - -begin; -create table keyvalue(id integer primary key, info jsonb); -create index nameindex on keyvalue((info->>'name')); -insert into keyvalue values (1, '{"name": "john", "data": "some data"}'); -update keyvalue set info='{"name": "john", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); -update keyvalue set info='{"name": "smith", "data": "some other data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); -update keyvalue set info='{"name": "smith", "data": "some more data"}' where id=1; -select pg_stat_get_xact_tuples_hot_updated('keyvalue'::regclass); -rollback; -- 2.40.0