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Allow read only connections during recovery, known as Hot Standby.

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Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record.

New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far.

This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required.

Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit.

Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
This commit is contained in:
Simon Riggs
2009-12-19 01:32:45 +00:00
parent 78a09145e0
commit efc16ea520
87 changed files with 6165 additions and 428 deletions
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33
src/backend/commands/vacuum.c
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@@ -13,7 +13,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.398 2009/12/09 21:57:51 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.399 2009/12/19 01:32:34 sriggs Exp $
*
*-------------------------------------------------------------------------
*/
@@ -141,6 +141,7 @@ typedef struct VRelStats
/* vtlinks array for tuple chain following - sorted by new_tid */
int num_vtlinks;
VTupleLink vtlinks;
TransactionId latestRemovedXid;
} VRelStats;
/*----------------------------------------------------------------------
@@ -224,7 +225,7 @@ static void scan_heap(VRelStats *vacrelstats, Relation onerel,
static bool repair_frag(VRelStats *vacrelstats, Relation onerel,
VacPageList vacuum_pages, VacPageList fraged_pages,
int nindexes, Relation *Irel);
static void move_chain_tuple(Relation rel,
static void move_chain_tuple(VRelStats *vacrelstats, Relation rel,
Buffer old_buf, Page old_page, HeapTuple old_tup,
Buffer dst_buf, Page dst_page, VacPage dst_vacpage,
ExecContext ec, ItemPointer ctid, bool cleanVpd);
@@ -237,7 +238,7 @@ static void update_hint_bits(Relation rel, VacPageList fraged_pages,
int num_moved);
static void vacuum_heap(VRelStats *vacrelstats, Relation onerel,
VacPageList vacpagelist);
static void vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage);
static void vacuum_page(VRelStats *vacrelstats, Relation onerel, Buffer buffer, VacPage vacpage);
static void vacuum_index(VacPageList vacpagelist, Relation indrel,
double num_tuples, int keep_tuples);
static void scan_index(Relation indrel, double num_tuples);
@@ -1300,6 +1301,7 @@ full_vacuum_rel(Relation onerel, VacuumStmt *vacstmt)
vacrelstats->rel_tuples = 0;
vacrelstats->rel_indexed_tuples = 0;
vacrelstats->hasindex = false;
vacrelstats->latestRemovedXid = InvalidTransactionId;
/* scan the heap */
vacuum_pages.num_pages = fraged_pages.num_pages = 0;
@@ -1708,6 +1710,9 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
{
ItemId lpp;
HeapTupleHeaderAdvanceLatestRemovedXid(tuple.t_data,
&vacrelstats->latestRemovedXid);
/*
* Here we are building a temporary copy of the page with dead
* tuples removed. Below we will apply
@@ -2025,7 +2030,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
/* there are dead tuples on this page - clean them */
Assert(!isempty);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
vacuum_page(onerel, buf, last_vacuum_page);
vacuum_page(vacrelstats, onerel, buf, last_vacuum_page);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
else
@@ -2514,7 +2519,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
tuple.t_data = (HeapTupleHeader) PageGetItem(Cpage, Citemid);
tuple_len = tuple.t_len = ItemIdGetLength(Citemid);
move_chain_tuple(onerel, Cbuf, Cpage, &tuple,
move_chain_tuple(vacrelstats, onerel, Cbuf, Cpage, &tuple,
dst_buffer, dst_page, destvacpage,
&ec, &Ctid, vtmove[ti].cleanVpd);
@@ -2600,7 +2605,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
dst_page = BufferGetPage(dst_buffer);
/* if this page was not used before - clean it */
if (!PageIsEmpty(dst_page) && dst_vacpage->offsets_used == 0)
vacuum_page(onerel, dst_buffer, dst_vacpage);
vacuum_page(vacrelstats, onerel, dst_buffer, dst_vacpage);
}
else
LockBuffer(dst_buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -2753,7 +2758,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
HOLD_INTERRUPTS();
heldoff = true;
ForceSyncCommit();
(void) RecordTransactionCommit();
(void) RecordTransactionCommit(true);
}
/*
@@ -2781,7 +2786,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);
if (!PageIsEmpty(page))
vacuum_page(onerel, buf, *curpage);
vacuum_page(vacrelstats, onerel, buf, *curpage);
UnlockReleaseBuffer(buf);
}
}
@@ -2917,7 +2922,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
recptr = log_heap_clean(onerel, buf,
NULL, 0, NULL, 0,
unused, uncnt,
false);
vacrelstats->latestRemovedXid, false);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
@@ -2969,7 +2974,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
* already too long and almost unreadable.
*/
static void
move_chain_tuple(Relation rel,
move_chain_tuple(VRelStats *vacrelstats, Relation rel,
Buffer old_buf, Page old_page, HeapTuple old_tup,
Buffer dst_buf, Page dst_page, VacPage dst_vacpage,
ExecContext ec, ItemPointer ctid, bool cleanVpd)
@@ -3027,7 +3032,7 @@ move_chain_tuple(Relation rel,
int sv_offsets_used = dst_vacpage->offsets_used;
dst_vacpage->offsets_used = 0;
vacuum_page(rel, dst_buf, dst_vacpage);
vacuum_page(vacrelstats, rel, dst_buf, dst_vacpage);
dst_vacpage->offsets_used = sv_offsets_used;
}
@@ -3367,7 +3372,7 @@ vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages)
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, (*vacpage)->blkno,
RBM_NORMAL, vac_strategy);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
vacuum_page(onerel, buf, *vacpage);
vacuum_page(vacrelstats, onerel, buf, *vacpage);
UnlockReleaseBuffer(buf);
}
}
@@ -3397,7 +3402,7 @@ vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages)
* Caller must hold pin and lock on buffer.
*/
static void
vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage)
vacuum_page(VRelStats *vacrelstats, Relation onerel, Buffer buffer, VacPage vacpage)
{
Page page = BufferGetPage(buffer);
int i;
@@ -3426,7 +3431,7 @@ vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage)
recptr = log_heap_clean(onerel, buffer,
NULL, 0, NULL, 0,
vacpage->offsets, vacpage->offsets_free,
false);
vacrelstats->latestRemovedXid, false);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}