>From b264bfe61b315a5f65d72b9550592cc9f73bf0a8 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Tue, 31 Dec 2013 00:42:11 -0300 Subject: [PATCH 1/3] pg_burn_multixact utility Andres Freund, minor tweaks by me --- contrib/pageinspect/heapfuncs.c | 42 ++++++++++++++++++++++++++++++ contrib/pageinspect/pageinspect--1.1.sql | 5 ++++ src/backend/access/heap/heapam.c | 2 +- src/backend/access/transam/multixact.c | 12 +++++---- src/include/access/multixact.h | 3 ++- 5 files changed, 57 insertions(+), 7 deletions(-) diff --git a/contrib/pageinspect/heapfuncs.c b/contrib/pageinspect/heapfuncs.c index 6d8f6f1..93a3317 100644 --- a/contrib/pageinspect/heapfuncs.c +++ b/contrib/pageinspect/heapfuncs.c @@ -29,6 +29,8 @@ #include "funcapi.h" #include "utils/builtins.h" #include "miscadmin.h" +#include "access/multixact.h" +#include "access/transam.h" Datum heap_page_items(PG_FUNCTION_ARGS); @@ -224,3 +226,43 @@ heap_page_items(PG_FUNCTION_ARGS) else SRF_RETURN_DONE(fctx); } + +extern Datum +pg_burn_multixact(PG_FUNCTION_ARGS); +PG_FUNCTION_INFO_V1(pg_burn_multixact); + +Datum +pg_burn_multixact(PG_FUNCTION_ARGS) +{ + int rep = PG_GETARG_INT32(0); + int size = PG_GETARG_INT32(1); + MultiXactMember *members; + MultiXactId ret; + TransactionId id = ReadNewTransactionId() - size; + int i; + + if (rep < 1) + elog(ERROR, "need to burn, burn, burn"); + + members = palloc(size * sizeof(MultiXactMember)); + for (i = 0; i < size; i++) + { + members[i].xid = id++; + members[i].status = MultiXactStatusForShare; + + if (!TransactionIdIsNormal(members[i].xid)) + { + id = FirstNormalTransactionId; + members[i].xid = id++; + } + } + + MultiXactIdSetOldestMember(); + + for (i = 0; i < rep; i++) + { + ret = MultiXactIdCreateFromMembers(size, members, true); + } + + PG_RETURN_INT64((int64) ret); +} diff --git a/contrib/pageinspect/pageinspect--1.1.sql b/contrib/pageinspect/pageinspect--1.1.sql index 22a47d5..b895246 100644 --- a/contrib/pageinspect/pageinspect--1.1.sql +++ b/contrib/pageinspect/pageinspect--1.1.sql @@ -105,3 +105,8 @@ CREATE FUNCTION fsm_page_contents(IN page bytea) RETURNS text AS 'MODULE_PATHNAME', 'fsm_page_contents' LANGUAGE C STRICT; + +CREATE FUNCTION pg_burn_multixact(num int4, size int4) +RETURNS int4 +AS 'MODULE_PATHNAME', 'pg_burn_multixact' +LANGUAGE C STRICT; diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 90e9e6f..1b8469f 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -5544,7 +5544,7 @@ FreezeMultiXactId(MultiXactId multi, uint16 t_infomask, * Create a new multixact with the surviving members of the previous * one, to set as new Xmax in the tuple. */ - xid = MultiXactIdCreateFromMembers(nnewmembers, newmembers); + xid = MultiXactIdCreateFromMembers(nnewmembers, newmembers, false); *flags |= FRM_RETURN_IS_MULTI; } diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index 6ce0eb2..2f87a1e 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -349,7 +349,7 @@ MultiXactIdCreate(TransactionId xid1, MultiXactStatus status1, members[1].xid = xid2; members[1].status = status2; - newMulti = MultiXactIdCreateFromMembers(2, members); + newMulti = MultiXactIdCreateFromMembers(2, members, false); debug_elog3(DEBUG2, "Create: %s", mxid_to_string(newMulti, 2, members)); @@ -415,7 +415,7 @@ MultiXactIdExpand(MultiXactId multi, TransactionId xid, MultiXactStatus status) */ member.xid = xid; member.status = status; - newMulti = MultiXactIdCreateFromMembers(1, &member); + newMulti = MultiXactIdCreateFromMembers(1, &member, false); debug_elog4(DEBUG2, "Expand: %u has no members, create singleton %u", multi, newMulti); @@ -467,7 +467,7 @@ MultiXactIdExpand(MultiXactId multi, TransactionId xid, MultiXactStatus status) newMembers[j].xid = xid; newMembers[j++].status = status; - newMulti = MultiXactIdCreateFromMembers(j, newMembers); + newMulti = MultiXactIdCreateFromMembers(j, newMembers, false); pfree(members); pfree(newMembers); @@ -681,7 +681,7 @@ ReadNextMultiXactId(void) * NB: the passed members[] array will be sorted in-place. */ MultiXactId -MultiXactIdCreateFromMembers(int nmembers, MultiXactMember *members) +MultiXactIdCreateFromMembers(int nmembers, MultiXactMember *members, bool nocache) { MultiXactId multi; MultiXactOffset offset; @@ -701,7 +701,9 @@ MultiXactIdCreateFromMembers(int nmembers, MultiXactMember *members) * corner cases where someone else added us to a MultiXact without our * knowledge, but it's not worth checking for.) */ - multi = mXactCacheGetBySet(nmembers, members); + multi = nocache ? InvalidMultiXactId : + mXactCacheGetBySet(nmembers, members); + if (MultiXactIdIsValid(multi)) { debug_elog2(DEBUG2, "Create: in cache!"); diff --git a/src/include/access/multixact.h b/src/include/access/multixact.h index 6aceaeb..1180e1f 100644 --- a/src/include/access/multixact.h +++ b/src/include/access/multixact.h @@ -79,10 +79,11 @@ typedef struct xl_multixact_create extern MultiXactId MultiXactIdCreate(TransactionId xid1, MultiXactStatus status1, TransactionId xid2, MultiXactStatus status2); +extern MultiXactId CreateMultiXactId(int nmembers, MultiXactMember *members, bool nocache); extern MultiXactId MultiXactIdExpand(MultiXactId multi, TransactionId xid, MultiXactStatus status); extern MultiXactId MultiXactIdCreateFromMembers(int nmembers, - MultiXactMember *members); + MultiXactMember *members, bool nocache); extern MultiXactId ReadNextMultiXactId(void); extern bool MultiXactIdIsRunning(MultiXactId multi, bool isLockOnly); -- 1.7.10.4