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Optionally prefetch referenced data in recovery. 

Introduce a new GUC recovery_prefetch, disabled by default.  When
enabled, look ahead in the WAL and try to initiate asynchronous reading
of referenced data blocks that are not yet cached in our buffer pool.
For now, this is done with posix_fadvise(), which has several caveats.
Better mechanisms will follow in later work on the I/O subsystem.

The GUC maintenance_io_concurrency is used to limit the number of
concurrent I/Os we allow ourselves to initiate, based on pessimistic
heuristics used to infer that I/Os have begun and completed.

The GUC wal_decode_buffer_size is used to limit the maximum distance we
are prepared to read ahead in the WAL to find uncached blocks.

Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> (parts)
Reviewed-by: Andres Freund <andres@anarazel.de> (parts)
Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> (parts)
Tested-by: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com>
Tested-by: Dmitry Dolgov <9erthalion6@gmail.com>
Tested-by: Sait Talha Nisanci <Sait.Nisanci@microsoft.com>
Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
This commit is contained in:
Thomas Munro 2021-04-08 23:03:43 +12:00
parent f003d9f872
commit 1d257577e0
23 changed files with 1502 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
doc/src/sgml/config.sgml
View File

@ -3565,6 +3565,89 @@ include_dir 'conf.d'
</variablelist>
</sect2>
<sect2 id="runtime-config-wal-recovery">
<title>Recovery</title>
<indexterm>
<primary>configuration</primary>
<secondary>of recovery</secondary>
<tertiary>general settings</tertiary>
</indexterm>
<para>
This section describes the settings that apply to recovery in general,
affecting crash recovery, streaming replication and archive-based
replication.
</para>
<variablelist>
<varlistentry id="guc-recovery-prefetch" xreflabel="recovery_prefetch">
<term><varname>recovery_prefetch</varname> (<type>boolean</type>)
<indexterm>
<primary><varname>recovery_prefetch</varname> configuration parameter</primary>
</indexterm>
</term>
<listitem>
<para>
Whether to try to prefetch blocks that are referenced in the WAL that
are not yet in the buffer pool, during recovery. Prefetching blocks
that will soon be needed can reduce I/O wait times in some workloads.
See also the <xref linkend="guc-wal-decode-buffer-size"/> and
<xref linkend="guc-maintenance-io-concurrency"/> settings, which limit
prefetching activity.
This setting is disabled by default.
</para>
<para>
This feature currently depends on an effective
<function>posix_fadvise</function> function, which some
operating systems lack.
</para>
</listitem>
</varlistentry>
<varlistentry id="guc-recovery-prefetch-fpw" xreflabel="recovery_prefetch_fpw">
<term><varname>recovery_prefetch_fpw</varname> (<type>boolean</type>)
<indexterm>
<primary><varname>recovery_prefetch_fpw</varname> configuration parameter</primary>
</indexterm>
</term>
<listitem>
<para>
Whether to prefetch blocks that were logged with full page images,
during recovery. Often this doesn't help, since such blocks will not
be read the first time they are needed and might remain in the buffer
pool after that. However, on file systems with a block size larger
than
<productname>PostgreSQL</productname>'s, prefetching can avoid a
costly read-before-write when a blocks are later written.
The default is off.
</para>
</listitem>
</varlistentry>
<varlistentry id="guc-wal-decode-buffer-size" xreflabel="wal_decode_buffer_size">
<term><varname>wal_decode_buffer_size</varname> (<type>integer</type>)
<indexterm>
<primary><varname>wal_decode_buffer_size</varname> configuration parameter</primary>
</indexterm>
</term>
<listitem>
<para>
A limit on how far ahead the server can look in the WAL, to find
blocks to prefetch. Setting it too high might be counterproductive,
if it means that data falls out of the
kernel cache before it is needed. If this value is specified without
units, it is taken as bytes.
The default is 512kB.
</para>
</listitem>
</varlistentry>
</variablelist>
</sect2>
<sect2 id="runtime-config-wal-archive-recovery">
<title>Archive Recovery</title>

86
doc/src/sgml/monitoring.sgml
View File

@ -337,6 +337,13 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
</entry>
</row>
<row>
<entry><structname>pg_stat_prefetch_recovery</structname><indexterm><primary>pg_stat_prefetch_recovery</primary></indexterm></entry>
<entry>Only one row, showing statistics about blocks prefetched during recovery.
See <xref linkend="pg-stat-prefetch-recovery-view"/> for details.
</entry>
</row>
<row>
<entry><structname>pg_stat_subscription</structname><indexterm><primary>pg_stat_subscription</primary></indexterm></entry>
<entry>At least one row per subscription, showing information about
@ -2917,6 +2924,78 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
copy of the subscribed tables.
</para>
<table id="pg-stat-prefetch-recovery-view" xreflabel="pg_stat_prefetch_recovery">
<title><structname>pg_stat_prefetch_recovery</structname> View</title>
<tgroup cols="3">
<thead>
<row>
<entry>Column</entry>
<entry>Type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><structfield>prefetch</structfield></entry>
<entry><type>bigint</type></entry>
<entry>Number of blocks prefetched because they were not in the buffer pool</entry>
</row>
<row>
<entry><structfield>skip_hit</structfield></entry>
<entry><type>bigint</type></entry>
<entry>Number of blocks not prefetched because they were already in the buffer pool</entry>
</row>
<row>
<entry><structfield>skip_new</structfield></entry>
<entry><type>bigint</type></entry>
<entry>Number of blocks not prefetched because they were new (usually relation extension)</entry>
</row>
<row>
<entry><structfield>skip_fpw</structfield></entry>
<entry><type>bigint</type></entry>
<entry>Number of blocks not prefetched because a full page image was included in the WAL and <xref linkend="guc-recovery-prefetch-fpw"/> was set to <literal>off</literal></entry>
</row>
<row>
<entry><structfield>skip_seq</structfield></entry>
<entry><type>bigint</type></entry>
<entry>Number of blocks not prefetched because of repeated access</entry>
</row>
<row>
<entry><structfield>distance</structfield></entry>
<entry><type>integer</type></entry>
<entry>How far ahead of recovery the prefetcher is currently reading, in bytes</entry>
</row>
<row>
<entry><structfield>queue_depth</structfield></entry>
<entry><type>integer</type></entry>
<entry>How many prefetches have been initiated but are not yet known to have completed</entry>
</row>
<row>
<entry><structfield>avg_distance</structfield></entry>
<entry><type>float4</type></entry>
<entry>How far ahead of recovery the prefetcher is on average, while recovery is not idle</entry>
</row>
<row>
<entry><structfield>avg_queue_depth</structfield></entry>
<entry><type>float4</type></entry>
<entry>Average number of prefetches in flight while recovery is not idle</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The <structname>pg_stat_prefetch_recovery</structname> view will contain only
one row. It is filled with nulls if recovery is not running or WAL
prefetching is not enabled. See <xref linkend="guc-recovery-prefetch"/>
for more information. The counters in this view are reset whenever the
<xref linkend="guc-recovery-prefetch"/>,
<xref linkend="guc-recovery-prefetch-fpw"/> or
<xref linkend="guc-maintenance-io-concurrency"/> setting is changed and
the server configuration is reloaded.
</para>
<table id="pg-stat-subscription" xreflabel="pg_stat_subscription">
<title><structname>pg_stat_subscription</structname> View</title>
<tgroup cols="1">
@ -5049,8 +5128,11 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
all the counters shown in
the <structname>pg_stat_bgwriter</structname>
view, <literal>archiver</literal> to reset all the counters shown in
the <structname>pg_stat_archiver</structname> view or <literal>wal</literal>
to reset all the counters shown in the <structname>pg_stat_wal</structname> view.
the <structname>pg_stat_archiver</structname> view,
<literal>wal</literal> to reset all the counters shown in the
<structname>pg_stat_wal</structname> view or
<literal>prefetch_recovery</literal> to reset all the counters shown
in the <structname>pg_stat_prefetch_recovery</structname> view.
</para>
<para>
This function is restricted to superusers by default, but other users

17
doc/src/sgml/wal.sgml
View File

@ -803,6 +803,23 @@
counted as <literal>wal_write</literal> and <literal>wal_sync</literal>
in <structname>pg_stat_wal</structname>, respectively.
</para>
<para>
The <xref linkend="guc-recovery-prefetch"/> parameter can
be used to improve I/O performance during recovery by instructing
<productname>PostgreSQL</productname> to initiate reads
of disk blocks that will soon be needed but are not currently in
<productname>PostgreSQL</productname>'s buffer pool.
The <xref linkend="guc-maintenance-io-concurrency"/> and
<xref linkend="guc-wal-decode-buffer-size"/> settings limit prefetching
concurrency and distance, respectively. The
prefetching mechanism is most likely to be effective on systems
with <varname>full_page_writes</varname> set to
<varname>off</varname> (where that is safe), and where the working
set is larger than RAM. By default, prefetching in recovery is enabled
on operating systems that have <function>posix_fadvise</function>
support.
</para>
</sect1>
<sect1 id="wal-internals">

1
src/backend/access/transam/Makefile
View File

@ -31,6 +31,7 @@ OBJS = \
xlogarchive.o \
xlogfuncs.o \
xloginsert.o \
xlogprefetch.o \
xlogreader.o \
xlogutils.o

50
src/backend/access/transam/xlog.c
View File

@ -35,6 +35,7 @@
#include "access/xlog_internal.h"
#include "access/xlogarchive.h"
#include "access/xloginsert.h"
#include "access/xlogprefetch.h"
#include "access/xlogreader.h"
#include "access/xlogutils.h"
#include "catalog/catversion.h"
@ -110,6 +111,7 @@ int CommitDelay = 0; /* precommit delay in microseconds */
int CommitSiblings = 5; /* # concurrent xacts needed to sleep */
int wal_retrieve_retry_interval = 5000;
int max_slot_wal_keep_size_mb = -1;
int wal_decode_buffer_size = 512 * 1024;
bool track_wal_io_timing = false;
#ifdef WAL_DEBUG
@ -910,7 +912,8 @@ static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli,
XLogSource source, bool notfoundOk);
static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source);
static bool XLogPageRead(XLogReaderState *state,
bool fetching_ckpt, int emode, bool randAccess);
bool fetching_ckpt, int emode, bool randAccess,
bool nowait);
static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
bool fetching_ckpt,
XLogRecPtr tliRecPtr,
@ -1461,7 +1464,7 @@ checkXLogConsistency(XLogReaderState *record)
* temporary page.
*/
buf = XLogReadBufferExtended(rnode, forknum, blkno,
RBM_NORMAL_NO_LOG);
RBM_NORMAL_NO_LOG, InvalidBuffer);
if (!BufferIsValid(buf))
continue;
@ -3729,7 +3732,6 @@ XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli,
snprintf(activitymsg, sizeof(activitymsg), "waiting for %s",
xlogfname);
set_ps_display(activitymsg);
restoredFromArchive = RestoreArchivedFile(path, xlogfname,
"RECOVERYXLOG",
wal_segment_size,
@ -4389,9 +4391,9 @@ ReadRecord(XLogReaderState *xlogreader, int emode,
while ((result = XLogReadRecord(xlogreader, &record, &errormsg))
== XLREAD_NEED_DATA)
{
if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess))
if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess,
false /* wait for data if streaming */))
break;
}
ReadRecPtr = xlogreader->ReadRecPtr;
@ -6632,6 +6634,12 @@ StartupXLOG(void)
errdetail("Failed while allocating a WAL reading processor.")));
xlogreader->system_identifier = ControlFile->system_identifier;
/*
* Set the WAL decode buffer size. This limits how far ahead we can read
* in the WAL.
*/
XLogReaderSetDecodeBuffer(xlogreader, NULL, wal_decode_buffer_size);
/*
* Allocate two page buffers dedicated to WAL consistency checks. We do
* it this way, rather than just making static arrays, for two reasons:
@ -7312,6 +7320,7 @@ StartupXLOG(void)
{
ErrorContextCallback errcallback;
TimestampTz xtime;
XLogPrefetchState prefetch;
PGRUsage ru0;
pg_rusage_init(&ru0);
@ -7322,6 +7331,9 @@ StartupXLOG(void)
(errmsg("redo starts at %X/%X",
LSN_FORMAT_ARGS(ReadRecPtr))));
/* Prepare to prefetch, if configured. */
XLogPrefetchBegin(&prefetch, xlogreader);
/*
* main redo apply loop
*/
@ -7351,6 +7363,14 @@ StartupXLOG(void)
/* Handle interrupt signals of startup process */
HandleStartupProcInterrupts();
/* Perform WAL prefetching, if enabled. */
while (XLogPrefetch(&prefetch, xlogreader->ReadRecPtr) == XLREAD_NEED_DATA)
{
if (!XLogPageRead(xlogreader, false, LOG, false,
true /* don't wait for streaming data */))
break;
}
/*
* Pause WAL replay, if requested by a hot-standby session via
* SetRecoveryPause().
@ -7524,6 +7544,9 @@ StartupXLOG(void)
*/
if (AllowCascadeReplication())
WalSndWakeup();
/* Reset the prefetcher. */
XLogPrefetchReconfigure();
}
/* Exit loop if we reached inclusive recovery target */
@ -7540,6 +7563,7 @@ StartupXLOG(void)
/*
* end of main redo apply loop
*/
XLogPrefetchEnd(&prefetch);
if (reachedRecoveryTarget)
{
@ -12109,10 +12133,13 @@ CancelBackup(void)
* and call XLogPageRead() again with the same arguments. This lets
* XLogPageRead() to try fetching the record from another source, or to
* sleep and retry.
*
* If nowait is true, then return false immediately if the requested data isn't
* available yet.
*/
static bool
XLogPageRead(XLogReaderState *state,
bool fetching_ckpt, int emode, bool randAccess)
bool fetching_ckpt, int emode, bool randAccess, bool nowait)
{
char *readBuf = state->readBuf;
XLogRecPtr targetPagePtr = state->readPagePtr;
@ -12136,9 +12163,6 @@ XLogPageRead(XLogReaderState *state,
/*
* Request a restartpoint if we've replayed too much xlog since the
* last one.
*
* XXX Why is this here? Move it to recovery loop, since it's based
* on replay position, not read position?
*/
if (bgwriterLaunched)
{
@ -12163,6 +12187,12 @@ retry:
(readSource == XLOG_FROM_STREAM &&
flushedUpto < targetPagePtr + reqLen))
{
if (nowait)
{
XLogReaderSetInputData(state, -1);
return false;
}
if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen,
randAccess, fetching_ckpt,
targetRecPtr, state->seg.ws_segno))
@ -12396,6 +12426,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
*/
currentSource = XLOG_FROM_STREAM;
startWalReceiver = true;
XLogPrefetchReconfigure();
break;
case XLOG_FROM_STREAM:
@ -12651,6 +12682,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
else
havedata = false;
}
if (havedata)
{
/*

922
src/backend/access/transam/xlogprefetch.c Normal file
View File

@ -0,0 +1,922 @@
/*-------------------------------------------------------------------------
*
* xlogprefetch.c
* Prefetching support for recovery.
*
* Portions Copyright (c) 2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/access/transam/xlogprefetch.c
*
* The goal of this module is to read future WAL records and issue
* PrefetchSharedBuffer() calls for referenced blocks, so that we avoid I/O
* stalls in the main recovery loop.
*
* When examining a WAL record from the future, we need to consider that a
* referenced block or segment file might not exist on disk until this record
* or some earlier record has been replayed. After a crash, a file might also
* be missing because it was dropped by a later WAL record; in that case, it
* will be recreated when this record is replayed. These cases are handled by
* recognizing them and adding a "filter" that prevents all prefetching of a
* certain block range until the present WAL record has been replayed. Blocks
* skipped for these reasons are counted as "skip_new" (that is, cases where we
* didn't try to prefetch "new" blocks).
*
* Blocks found in the buffer pool already are counted as "skip_hit".
* Repeated access to the same buffer is detected and skipped, and this is
* counted with "skip_seq". Blocks that were logged with FPWs are skipped if
* recovery_prefetch_fpw is off, since on most systems there will be no I/O
* stall; this is counted with "skip_fpw".
*
* The only way we currently have to know that an I/O initiated with
* PrefetchSharedBuffer() has that recovery will eventually call ReadBuffer(),
* and perform a synchronous read. Therefore, we track the number of
* potentially in-flight I/Os by using a circular buffer of LSNs. When it's
* full, we have to wait for recovery to replay records so that the queue
* depth can be reduced, before we can do any more prefetching. Ideally, this
* keeps us the right distance ahead to respect maintenance_io_concurrency.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/xlog.h"
#include "access/xlogprefetch.h"
#include "access/xlogreader.h"
#include "access/xlogutils.h"
#include "catalog/storage_xlog.h"
#include "utils/fmgrprotos.h"
#include "utils/timestamp.h"
#include "funcapi.h"
#include "pgstat.h"
#include "miscadmin.h"
#include "port/atomics.h"
#include "storage/bufmgr.h"
#include "storage/shmem.h"
#include "storage/smgr.h"
#include "utils/guc.h"
#include "utils/hsearch.h"
/*
* Sample the queue depth and distance every time we replay this much WAL.
* This is used to compute avg_queue_depth and avg_distance for the log
* message that appears at the end of crash recovery. It's also used to send
* messages periodically to the stats collector, to save the counters on disk.
*/
#define XLOGPREFETCHER_SAMPLE_DISTANCE 0x40000
/* GUCs */
bool recovery_prefetch = false;
bool recovery_prefetch_fpw = false;
int XLogPrefetchReconfigureCount;
/*
* A prefetcher object. There is at most one of these in existence at a time,
* recreated whenever there is a configuration change.
*/
struct XLogPrefetcher
{
/* Reader and current reading state. */
XLogReaderState *reader;
DecodedXLogRecord *record;
int next_block_id;
bool shutdown;
/* Details of last prefetch to skip repeats and seq scans. */
SMgrRelation last_reln;
RelFileNode last_rnode;
BlockNumber last_blkno;
/* Online averages. */
uint64 samples;
double avg_queue_depth;
double avg_distance;
XLogRecPtr next_sample_lsn;
/* Book-keeping required to avoid accessing non-existing blocks. */
HTAB *filter_table;
dlist_head filter_queue;
/* Book-keeping required to limit concurrent prefetches. */
int prefetch_head;
int prefetch_tail;
int prefetch_queue_size;
XLogRecPtr prefetch_queue[MAX_IO_CONCURRENCY + 1];
};
/*
* A temporary filter used to track block ranges that haven't been created
* yet, whole relations that haven't been created yet, and whole relations
* that we must assume have already been dropped.
*/
typedef struct XLogPrefetcherFilter
{
RelFileNode rnode;
XLogRecPtr filter_until_replayed;
BlockNumber filter_from_block;
dlist_node link;
} XLogPrefetcherFilter;
/*
* Counters exposed in shared memory for pg_stat_prefetch_recovery.
*/
typedef struct XLogPrefetchStats
{
pg_atomic_uint64 reset_time; /* Time of last reset. */
pg_atomic_uint64 prefetch; /* Prefetches initiated. */
pg_atomic_uint64 skip_hit; /* Blocks already buffered. */
pg_atomic_uint64 skip_new; /* New/missing blocks filtered. */
pg_atomic_uint64 skip_fpw; /* FPWs skipped. */
pg_atomic_uint64 skip_seq; /* Repeat blocks skipped. */
float avg_distance;
float avg_queue_depth;
/* Reset counters */
pg_atomic_uint32 reset_request;
uint32 reset_handled;
/* Dynamic values */
int distance; /* Number of bytes ahead in the WAL. */
int queue_depth; /* Number of I/Os possibly in progress. */
} XLogPrefetchStats;
static inline void XLogPrefetcherAddFilter(XLogPrefetcher *prefetcher,
RelFileNode rnode,
BlockNumber blockno,
XLogRecPtr lsn);
static inline bool XLogPrefetcherIsFiltered(XLogPrefetcher *prefetcher,
RelFileNode rnode,
BlockNumber blockno);
static inline void XLogPrefetcherCompleteFilters(XLogPrefetcher *prefetcher,
XLogRecPtr replaying_lsn);
static inline void XLogPrefetcherInitiatedIO(XLogPrefetcher *prefetcher,
XLogRecPtr prefetching_lsn);
static inline void XLogPrefetcherCompletedIO(XLogPrefetcher *prefetcher,
XLogRecPtr replaying_lsn);
static inline bool XLogPrefetcherSaturated(XLogPrefetcher *prefetcher);
static bool XLogPrefetcherScanRecords(XLogPrefetcher *prefetcher,
XLogRecPtr replaying_lsn);
static bool XLogPrefetcherScanBlocks(XLogPrefetcher *prefetcher);
static void XLogPrefetchSaveStats(void);
static void XLogPrefetchRestoreStats(void);
static XLogPrefetchStats *SharedStats;
size_t
XLogPrefetchShmemSize(void)
{
return sizeof(XLogPrefetchStats);
}
static void
XLogPrefetchResetStats(void)
{
pg_atomic_write_u64(&SharedStats->reset_time, GetCurrentTimestamp());
pg_atomic_write_u64(&SharedStats->prefetch, 0);
pg_atomic_write_u64(&SharedStats->skip_hit, 0);
pg_atomic_write_u64(&SharedStats->skip_new, 0);
pg_atomic_write_u64(&SharedStats->skip_fpw, 0);
pg_atomic_write_u64(&SharedStats->skip_seq, 0);
SharedStats->avg_distance = 0;
SharedStats->avg_queue_depth = 0;
}
void
XLogPrefetchShmemInit(void)
{
bool found;
SharedStats = (XLogPrefetchStats *)
ShmemInitStruct("XLogPrefetchStats",
sizeof(XLogPrefetchStats),
&found);
if (!found)
{
pg_atomic_init_u32(&SharedStats->reset_request, 0);
SharedStats->reset_handled = 0;
pg_atomic_init_u64(&SharedStats->reset_time, GetCurrentTimestamp());
pg_atomic_init_u64(&SharedStats->prefetch, 0);
pg_atomic_init_u64(&SharedStats->skip_hit, 0);
pg_atomic_init_u64(&SharedStats->skip_new, 0);
pg_atomic_init_u64(&SharedStats->skip_fpw, 0);
pg_atomic_init_u64(&SharedStats->skip_seq, 0);
SharedStats->avg_distance = 0;
SharedStats->avg_queue_depth = 0;
SharedStats->distance = 0;
SharedStats->queue_depth = 0;
}
}
/*
* Called when any GUC is changed that affects prefetching.
*/
void
XLogPrefetchReconfigure(void)
{
XLogPrefetchReconfigureCount++;
}
/*
* Called by any backend to request that the stats be reset.
*/
void
XLogPrefetchRequestResetStats(void)
{
pg_atomic_fetch_add_u32(&SharedStats->reset_request, 1);
}
/*
* Tell the stats collector to serialize the shared memory counters into the
* stats file.
*/
static void
XLogPrefetchSaveStats(void)
{
PgStat_RecoveryPrefetchStats serialized = {
.prefetch = pg_atomic_read_u64(&SharedStats->prefetch),
.skip_hit = pg_atomic_read_u64(&SharedStats->skip_hit),
.skip_new = pg_atomic_read_u64(&SharedStats->skip_new),
.skip_fpw = pg_atomic_read_u64(&SharedStats->skip_fpw),
.skip_seq = pg_atomic_read_u64(&SharedStats->skip_seq),
.stat_reset_timestamp = pg_atomic_read_u64(&SharedStats->reset_time)
};
pgstat_send_recoveryprefetch(&serialized);
}
/*
* Try to restore the shared memory counters from the stats file.
*/
static void
XLogPrefetchRestoreStats(void)
{
PgStat_RecoveryPrefetchStats *serialized = pgstat_fetch_recoveryprefetch();
if (serialized->stat_reset_timestamp != 0)
{
pg_atomic_write_u64(&SharedStats->prefetch, serialized->prefetch);
pg_atomic_write_u64(&SharedStats->skip_hit, serialized->skip_hit);
pg_atomic_write_u64(&SharedStats->skip_new, serialized->skip_new);
pg_atomic_write_u64(&SharedStats->skip_fpw, serialized->skip_fpw);
pg_atomic_write_u64(&SharedStats->skip_seq, serialized->skip_seq);
pg_atomic_write_u64(&SharedStats->reset_time, serialized->stat_reset_timestamp);
}
}
/*
* Increment a counter in shared memory. This is equivalent to *counter++ on a
* plain uint64 without any memory barrier or locking, except on platforms
* where readers can't read uint64 without possibly observing a torn value.
*/
static inline void
XLogPrefetchIncrement(pg_atomic_uint64 *counter)
{
Assert(AmStartupProcess() || !IsUnderPostmaster);
pg_atomic_write_u64(counter, pg_atomic_read_u64(counter) + 1);
}
/*
* Initialize an XLogPrefetchState object and restore the last saved
* statistics from disk.
*/
void
XLogPrefetchBegin(XLogPrefetchState *state, XLogReaderState *reader)
{
XLogPrefetchRestoreStats();
/* We'll reconfigure on the first call to XLogPrefetch(). */
state->reader = reader;
state->prefetcher = NULL;
state->reconfigure_count = XLogPrefetchReconfigureCount - 1;
}
/*
* Shut down the prefetching infrastructure, if configured.
*/
void
XLogPrefetchEnd(XLogPrefetchState *state)
{
XLogPrefetchSaveStats();
if (state->prefetcher)
XLogPrefetcherFree(state->prefetcher);
state->prefetcher = NULL;
SharedStats->queue_depth = 0;
SharedStats->distance = 0;
}
/*
* Create a prefetcher that is ready to begin prefetching blocks referenced by
* WAL records.
*/
XLogPrefetcher *
XLogPrefetcherAllocate(XLogReaderState *reader)
{
XLogPrefetcher *prefetcher;
static HASHCTL hash_table_ctl = {
.keysize = sizeof(RelFileNode),
.entrysize = sizeof(XLogPrefetcherFilter)
};
/*
* The size of the queue is based on the maintenance_io_concurrency
* setting. In theory we might have a separate queue for each tablespace,
* but it's not clear how that should work, so for now we'll just use the
* general GUC to rate-limit all prefetching. The queue has space for up
* the highest possible value of the GUC + 1, because our circular buffer
* has a gap between head and tail when full.
*/
prefetcher = palloc0(sizeof(XLogPrefetcher));
prefetcher->prefetch_queue_size = maintenance_io_concurrency + 1;
prefetcher->reader = reader;
prefetcher->filter_table = hash_create("XLogPrefetcherFilterTable", 1024,
&hash_table_ctl,
HASH_ELEM | HASH_BLOBS);
dlist_init(&prefetcher->filter_queue);
SharedStats->queue_depth = 0;
SharedStats->distance = 0;
return prefetcher;
}
/*
* Destroy a prefetcher and release all resources.
*/
void
XLogPrefetcherFree(XLogPrefetcher *prefetcher)
{
/* Log final statistics. */
ereport(LOG,
(errmsg("recovery finished prefetching at %X/%X; "
"prefetch = " UINT64_FORMAT ", "
"skip_hit = " UINT64_FORMAT ", "
"skip_new = " UINT64_FORMAT ", "
"skip_fpw = " UINT64_FORMAT ", "
"skip_seq = " UINT64_FORMAT ", "
"avg_distance = %f, "
"avg_queue_depth = %f",
(uint32) (prefetcher->reader->EndRecPtr << 32),
(uint32) (prefetcher->reader->EndRecPtr),
pg_atomic_read_u64(&SharedStats->prefetch),
pg_atomic_read_u64(&SharedStats->skip_hit),
pg_atomic_read_u64(&SharedStats->skip_new),
pg_atomic_read_u64(&SharedStats->skip_fpw),
pg_atomic_read_u64(&SharedStats->skip_seq),
SharedStats->avg_distance,
SharedStats->avg_queue_depth)));
hash_destroy(prefetcher->filter_table);
pfree(prefetcher);
}
/*
* Called when recovery is replaying a new LSN, to check if we can read ahead.
*/
bool
XLogPrefetcherReadAhead(XLogPrefetcher *prefetcher, XLogRecPtr replaying_lsn)
{
uint32 reset_request;
/* If an error has occurred or we've hit the end of the WAL, do nothing. */
if (prefetcher->shutdown)
return false;
/*
* Have any in-flight prefetches definitely completed, judging by the LSN
* that is currently being replayed?
*/
XLogPrefetcherCompletedIO(prefetcher, replaying_lsn);
/*
* Do we already have the maximum permitted number of I/Os running
* (according to the information we have)? If so, we have to wait for at
* least one to complete, so give up early and let recovery catch up.
*/
if (XLogPrefetcherSaturated(prefetcher))
return false;
/*
* Can we drop any filters yet? This happens when the LSN that is
* currently being replayed has moved past a record that prevents
* prefetching of a block range, such as relation extension.
*/
XLogPrefetcherCompleteFilters(prefetcher, replaying_lsn);
/*
* Have we been asked to reset our stats counters? This is checked with
* an unsynchronized memory read, but we'll see it eventually and we'll be
* accessing that cache line anyway.
*/
reset_request = pg_atomic_read_u32(&SharedStats->reset_request);
if (reset_request != SharedStats->reset_handled)
{
XLogPrefetchResetStats();
SharedStats->reset_handled = reset_request;
prefetcher->avg_distance = 0;
prefetcher->avg_queue_depth = 0;
prefetcher->samples = 0;
}
/* OK, we can now try reading ahead. */
return XLogPrefetcherScanRecords(prefetcher, replaying_lsn);
}
/*
* Read ahead as far as we are allowed to, considering the LSN that recovery
* is currently replaying.
*
* Return true if the xlogreader would like more data.
*/
static bool
XLogPrefetcherScanRecords(XLogPrefetcher *prefetcher, XLogRecPtr replaying_lsn)
{
XLogReaderState *reader = prefetcher->reader;
DecodedXLogRecord *record;
Assert(!XLogPrefetcherSaturated(prefetcher));
for (;;)
{
char *error;
int64 distance;
/* If we don't already have a record, then try to read one. */
if (prefetcher->record == NULL)
{
switch (XLogReadAhead(reader, &record, &error))
{
case XLREAD_NEED_DATA:
return true;
case XLREAD_FAIL:
if (error)
ereport(LOG,
(errmsg("recovery no longer prefetching: %s",
error)));
else
ereport(LOG,
(errmsg("recovery no longer prefetching")));
prefetcher->shutdown = true;
SharedStats->queue_depth = 0;
SharedStats->distance = 0;
return false;
case XLREAD_FULL:
return false;
case XLREAD_SUCCESS:
prefetcher->record = record;
prefetcher->next_block_id = 0;
break;
}
}
else
{
/*
* We ran out of I/O queue while part way through a record. We'll
* carry on where we left off, according to next_block_id.
*/
record = prefetcher->record;
}
/* How far ahead of replay are we now? */
distance = record->lsn - replaying_lsn;
/* Update distance shown in shm. */
SharedStats->distance = distance;
/* Periodically recompute some statistics. */
if (unlikely(replaying_lsn >= prefetcher->next_sample_lsn))
{
/* Compute online averages. */
prefetcher->samples++;
if (prefetcher->samples == 1)
{
prefetcher->avg_distance = SharedStats->distance;
prefetcher->avg_queue_depth = SharedStats->queue_depth;
}
else
{
prefetcher->avg_distance +=
(SharedStats->distance - prefetcher->avg_distance) /
prefetcher->samples;
prefetcher->avg_queue_depth +=
(SharedStats->queue_depth - prefetcher->avg_queue_depth) /
prefetcher->samples;
}
/* Expose it in shared memory. */
SharedStats->avg_distance = prefetcher->avg_distance;
SharedStats->avg_queue_depth = prefetcher->avg_queue_depth;
/* Also periodically save the simple counters. */
XLogPrefetchSaveStats();
prefetcher->next_sample_lsn =
replaying_lsn + XLOGPREFETCHER_SAMPLE_DISTANCE;
}
/* Are we not far enough ahead? */
if (distance <= 0)
{
/* XXX Is this still possible? */
prefetcher->record = NULL; /* skip this record */
continue;
}
/*
* If this is a record that creates a new SMGR relation, we'll avoid
* prefetching anything from that rnode until it has been replayed.
*/
if (replaying_lsn < record->lsn &&
record->header.xl_rmid == RM_SMGR_ID &&
(record->header.xl_info & ~XLR_INFO_MASK) == XLOG_SMGR_CREATE)
{
xl_smgr_create *xlrec = (xl_smgr_create *) record->main_data;
XLogPrefetcherAddFilter(prefetcher, xlrec->rnode, 0, record->lsn);
}
/* Scan the record's block references. */
if (!XLogPrefetcherScanBlocks(prefetcher))
return false;
/* Advance to the next record. */
prefetcher->record = NULL;
}
}
/*
* Scan the current record for block references, and consider prefetching.
*
* Return true if we processed the current record to completion and still have
* queue space to process a new record, and false if we saturated the I/O
* queue and need to wait for recovery to advance before we continue.
*/
static bool
XLogPrefetcherScanBlocks(XLogPrefetcher *prefetcher)
{
DecodedXLogRecord *record = prefetcher->record;
Assert(!XLogPrefetcherSaturated(prefetcher));
/*
* We might already have been partway through processing this record when
* our queue became saturated, so we need to start where we left off.
*/
for (int block_id = prefetcher->next_block_id;
block_id <= record->max_block_id;
++block_id)
{
DecodedBkpBlock *block = &record->blocks[block_id];
PrefetchBufferResult prefetch;
SMgrRelation reln;
/* Ignore everything but the main fork for now. */
if (block->forknum != MAIN_FORKNUM)
continue;
/*
* If there is a full page image attached, we won't be reading the
* page, so you might think we should skip it. However, if the
* underlying filesystem uses larger logical blocks than us, it might
* still need to perform a read-before-write some time later.
* Therefore, only prefetch if configured to do so.
*/
if (block->has_image && !recovery_prefetch_fpw)
{
XLogPrefetchIncrement(&SharedStats->skip_fpw);
continue;
}
/*
* If this block will initialize a new page then it's probably a
* relation extension. Since that might create a new segment, we
* can't try to prefetch this block until the record has been
* replayed, or we might try to open a file that doesn't exist yet.
*/
if (block->flags & BKPBLOCK_WILL_INIT)
{
XLogPrefetcherAddFilter(prefetcher, block->rnode, block->blkno,
record->lsn);
XLogPrefetchIncrement(&SharedStats->skip_new);
continue;
}
/* Should we skip this block due to a filter? */
if (XLogPrefetcherIsFiltered(prefetcher, block->rnode, block->blkno))
{
XLogPrefetchIncrement(&SharedStats->skip_new);
continue;
}
/* Fast path for repeated references to the same relation. */
if (RelFileNodeEquals(block->rnode, prefetcher->last_rnode))
{
/*
* If this is a repeat access to the same block, then skip it.
*
* XXX We could also check for last_blkno + 1 too, and also update
* last_blkno; it's not clear if the kernel would do a better job
* of sequential prefetching.
*/
if (block->blkno == prefetcher->last_blkno)
{
XLogPrefetchIncrement(&SharedStats->skip_seq);
continue;
}
/* We can avoid calling smgropen(). */
reln = prefetcher->last_reln;
}
else
{
/* Otherwise we have to open it. */
reln = smgropen(block->rnode, InvalidBackendId);
prefetcher->last_rnode = block->rnode;
prefetcher->last_reln = reln;
}
prefetcher->last_blkno = block->blkno;
/* Try to prefetch this block! */
prefetch = PrefetchSharedBuffer(reln, block->forknum, block->blkno);
if (BufferIsValid(prefetch.recent_buffer))
{
/*
* It was already cached, so do nothing. We'll remember the
* buffer, so that recovery can try to avoid looking it up again.
*/
block->recent_buffer = prefetch.recent_buffer;
XLogPrefetchIncrement(&SharedStats->skip_hit);
}
else if (prefetch.initiated_io)
{
/*
* I/O has possibly been initiated (though we don't know if it was
* already cached by the kernel, so we just have to assume that it
* has due to lack of better information). Record this as an I/O
* in progress until eventually we replay this LSN.
*/
XLogPrefetchIncrement(&SharedStats->prefetch);
XLogPrefetcherInitiatedIO(prefetcher, record->lsn);
/*
* If the queue is now full, we'll have to wait before processing
* any more blocks from this record, or move to a new record if
* that was the last block.
*/
if (XLogPrefetcherSaturated(prefetcher))
{
prefetcher->next_block_id = block_id + 1;
return false;
}
}
else
{
/*
* Neither cached nor initiated. The underlying segment file
* doesn't exist. Presumably it will be unlinked by a later WAL
* record. When recovery reads this block, it will use the
* EXTENSION_CREATE_RECOVERY flag. We certainly don't want to do
* that sort of thing while merely prefetching, so let's just
* ignore references to this relation until this record is
* replayed, and let recovery create the dummy file or complain if
* something is wrong.
*/
XLogPrefetcherAddFilter(prefetcher, block->rnode, 0,
record->lsn);
XLogPrefetchIncrement(&SharedStats->skip_new);
}
}
return true;
}
/*
* Expose statistics about recovery prefetching.
*/
Datum
pg_stat_get_prefetch_recovery(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_PREFETCH_RECOVERY_COLS 10
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
Datum values[PG_STAT_GET_PREFETCH_RECOVERY_COLS];
bool nulls[PG_STAT_GET_PREFETCH_RECOVERY_COLS];
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mod required, but it is not allowed in this context")));
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
if (pg_atomic_read_u32(&SharedStats->reset_request) != SharedStats->reset_handled)
{
/* There's an unhandled reset request, so just show NULLs */
for (int i = 0; i < PG_STAT_GET_PREFETCH_RECOVERY_COLS; ++i)
nulls[i] = true;
}
else
{
for (int i = 0; i < PG_STAT_GET_PREFETCH_RECOVERY_COLS; ++i)
nulls[i] = false;
}
values[0] = TimestampTzGetDatum(pg_atomic_read_u64(&SharedStats->reset_time));
values[1] = Int64GetDatum(pg_atomic_read_u64(&SharedStats->prefetch));
values[2] = Int64GetDatum(pg_atomic_read_u64(&SharedStats->skip_hit));
values[3] = Int64GetDatum(pg_atomic_read_u64(&SharedStats->skip_new));
values[4] = Int64GetDatum(pg_atomic_read_u64(&SharedStats->skip_fpw));
values[5] = Int64GetDatum(pg_atomic_read_u64(&SharedStats->skip_seq));
values[6] = Int32GetDatum(SharedStats->distance);
values[7] = Int32GetDatum(SharedStats->queue_depth);
values[8] = Float4GetDatum(SharedStats->avg_distance);
values[9] = Float4GetDatum(SharedStats->avg_queue_depth);
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
tuplestore_donestoring(tupstore);
return (Datum) 0;
}
/*
* Compute (n + 1) % prefetch_queue_size, assuming n < prefetch_queue_size,
* without using division.
*/
static inline int
XLogPrefetcherNext(XLogPrefetcher *prefetcher, int n)
{
int next = n + 1;
return next == prefetcher->prefetch_queue_size ? 0 : next;
}
/*
* Don't prefetch any blocks >= 'blockno' from a given 'rnode', until 'lsn'
* has been replayed.
*/
static inline void
XLogPrefetcherAddFilter(XLogPrefetcher *prefetcher, RelFileNode rnode,
BlockNumber blockno, XLogRecPtr lsn)
{
XLogPrefetcherFilter *filter;
bool found;
filter = hash_search(prefetcher->filter_table, &rnode, HASH_ENTER, &found);
if (!found)
{
/*
* Don't allow any prefetching of this block or higher until replayed.
*/
filter->filter_until_replayed = lsn;
filter->filter_from_block = blockno;
dlist_push_head(&prefetcher->filter_queue, &filter->link);
}
else
{
/*
* We were already filtering this rnode. Extend the filter's lifetime
* to cover this WAL record, but leave the (presumably lower) block
* number there because we don't want to have to track individual
* blocks.
*/
filter->filter_until_replayed = lsn;
dlist_delete(&filter->link);
dlist_push_head(&prefetcher->filter_queue, &filter->link);
}
}
/*
* Have we replayed the records that caused us to begin filtering a block
* range? That means that relations should have been created, extended or
* dropped as required, so we can drop relevant filters.
*/
static inline void
XLogPrefetcherCompleteFilters(XLogPrefetcher *prefetcher, XLogRecPtr replaying_lsn)
{
while (unlikely(!dlist_is_empty(&prefetcher->filter_queue)))
{
XLogPrefetcherFilter *filter = dlist_tail_element(XLogPrefetcherFilter,
link,
&prefetcher->filter_queue);
if (filter->filter_until_replayed >= replaying_lsn)
break;
dlist_delete(&filter->link);
hash_search(prefetcher->filter_table, filter, HASH_REMOVE, NULL);
}
}
/*
* Check if a given block should be skipped due to a filter.
*/
static inline bool
XLogPrefetcherIsFiltered(XLogPrefetcher *prefetcher, RelFileNode rnode,
BlockNumber blockno)
{
/*
* Test for empty queue first, because we expect it to be empty most of
* the time and we can avoid the hash table lookup in that case.
*/
if (unlikely(!dlist_is_empty(&prefetcher->filter_queue)))
{
XLogPrefetcherFilter *filter = hash_search(prefetcher->filter_table, &rnode,
HASH_FIND, NULL);
if (filter && filter->filter_from_block <= blockno)
return true;
}
return false;
}
/*
* Insert an LSN into the queue. The queue must not be full already. This
* tracks the fact that we have (to the best of our knowledge) initiated an
* I/O, so that we can impose a cap on concurrent prefetching.
*/
static inline void
XLogPrefetcherInitiatedIO(XLogPrefetcher *prefetcher,
XLogRecPtr prefetching_lsn)
{
Assert(!XLogPrefetcherSaturated(prefetcher));
prefetcher->prefetch_queue[prefetcher->prefetch_head] = prefetching_lsn;
prefetcher->prefetch_head =
XLogPrefetcherNext(prefetcher, prefetcher->prefetch_head);
SharedStats->queue_depth++;
Assert(SharedStats->queue_depth <= prefetcher->prefetch_queue_size);
}
/*
* Have we replayed the records that caused us to initiate the oldest
* prefetches yet? That means that they're definitely finished, so we can can
* forget about them and allow ourselves to initiate more prefetches. For now
* we don't have any awareness of when I/O really completes.
*/
static inline void
XLogPrefetcherCompletedIO(XLogPrefetcher *prefetcher, XLogRecPtr replaying_lsn)
{
while (prefetcher->prefetch_head != prefetcher->prefetch_tail &&
prefetcher->prefetch_queue[prefetcher->prefetch_tail] < replaying_lsn)
{
prefetcher->prefetch_tail =
XLogPrefetcherNext(prefetcher, prefetcher->prefetch_tail);
SharedStats->queue_depth--;
Assert(SharedStats->queue_depth >= 0);
}
}
/*
* Check if the maximum allowed number of I/Os is already in flight.
*/
static inline bool
XLogPrefetcherSaturated(XLogPrefetcher *prefetcher)
{
int next = XLogPrefetcherNext(prefetcher, prefetcher->prefetch_head);
return next == prefetcher->prefetch_tail;
}
void
assign_recovery_prefetch(bool new_value, void *extra)
{
/* Reconfigure prefetching, because a setting it depends on changed. */
recovery_prefetch = new_value;
if (AmStartupProcess())
XLogPrefetchReconfigure();
}
void
assign_recovery_prefetch_fpw(bool new_value, void *extra)
{
/* Reconfigure prefetching, because a setting it depends on changed. */
recovery_prefetch_fpw = new_value;
if (AmStartupProcess())
XLogPrefetchReconfigure();
}

13
src/backend/access/transam/xlogreader.c
View File

@ -1927,6 +1927,8 @@ DecodeXLogRecord(XLogReaderState *state,
blk->has_image = ((fork_flags & BKPBLOCK_HAS_IMAGE) != 0);
blk->has_data = ((fork_flags & BKPBLOCK_HAS_DATA) != 0);
blk->recent_buffer = InvalidBuffer;
COPY_HEADER_FIELD(&blk->data_len, sizeof(uint16));
/* cross-check that the HAS_DATA flag is set iff data_length > 0 */
if (blk->has_data && blk->data_len == 0)
@ -2134,6 +2136,15 @@ err:
bool
XLogRecGetBlockTag(XLogReaderState *record, uint8 block_id,
RelFileNode *rnode, ForkNumber *forknum, BlockNumber *blknum)
{
return XLogRecGetRecentBuffer(record, block_id, rnode, forknum, blknum,
NULL);
}
bool
XLogRecGetRecentBuffer(XLogReaderState *record, uint8 block_id,
RelFileNode *rnode, ForkNumber *forknum,
BlockNumber *blknum, Buffer *recent_buffer)
{
DecodedBkpBlock *bkpb;
@ -2148,6 +2159,8 @@ XLogRecGetBlockTag(XLogReaderState *record, uint8 block_id,
*forknum = bkpb->forknum;
if (blknum)
*blknum = bkpb->blkno;
if (recent_buffer)
*recent_buffer = bkpb->recent_buffer;
return true;
}

23
src/backend/access/transam/xlogutils.c
View File

@ -335,11 +335,13 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
RelFileNode rnode;
ForkNumber forknum;
BlockNumber blkno;
Buffer recent_buffer;
Page page;
bool zeromode;
bool willinit;
if (!XLogRecGetBlockTag(record, block_id, &rnode, &forknum, &blkno))
if (!XLogRecGetRecentBuffer(record, block_id, &rnode, &forknum, &blkno,
&recent_buffer))
{
/* Caller specified a bogus block_id */
elog(PANIC, "failed to locate backup block with ID %d", block_id);
@ -361,7 +363,8 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
{
Assert(XLogRecHasBlockImage(record, block_id));
*buf = XLogReadBufferExtended(rnode, forknum, blkno,
get_cleanup_lock ? RBM_ZERO_AND_CLEANUP_LOCK : RBM_ZERO_AND_LOCK);
get_cleanup_lock ? RBM_ZERO_AND_CLEANUP_LOCK : RBM_ZERO_AND_LOCK,
recent_buffer);
page = BufferGetPage(*buf);
if (!RestoreBlockImage(record, block_id, page))
elog(ERROR, "failed to restore block image");
@ -390,7 +393,8 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
}
else
{
*buf = XLogReadBufferExtended(rnode, forknum, blkno, mode);
*buf = XLogReadBufferExtended(rnode, forknum, blkno, mode,
recent_buffer);
if (BufferIsValid(*buf))
{
if (mode != RBM_ZERO_AND_LOCK && mode != RBM_ZERO_AND_CLEANUP_LOCK)
@ -437,7 +441,8 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
*/
Buffer
XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
BlockNumber blkno, ReadBufferMode mode)
BlockNumber blkno, ReadBufferMode mode,
Buffer recent_buffer)
{
BlockNumber lastblock;
Buffer buffer;
@ -445,6 +450,15 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
Assert(blkno != P_NEW);
/* Do we have a clue where the buffer might be already? */
if (BufferIsValid(recent_buffer) &&
mode == RBM_NORMAL &&
ReadRecentBuffer(rnode, forknum, blkno, recent_buffer))
{
buffer = recent_buffer;
goto recent_buffer_fast_path;
}
/* Open the relation at smgr level */
smgr = smgropen(rnode, InvalidBackendId);
@ -503,6 +517,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
}
}
recent_buffer_fast_path:
if (mode == RBM_NORMAL)
{
/* check that page has been initialized */

14
src/backend/catalog/system_views.sql
View File

@ -911,6 +911,20 @@ CREATE VIEW pg_stat_wal_receiver AS
FROM pg_stat_get_wal_receiver() s
WHERE s.pid IS NOT NULL;
CREATE VIEW pg_stat_prefetch_recovery AS
SELECT
s.stats_reset,
s.prefetch,
s.skip_hit,
s.skip_new,
s.skip_fpw,
s.skip_seq,
s.distance,
s.queue_depth,
s.avg_distance,
s.avg_queue_depth
FROM pg_stat_get_prefetch_recovery() s;
CREATE VIEW pg_stat_subscription AS
SELECT
su.oid AS subid,

103
src/backend/postmaster/pgstat.c
View File

@ -38,6 +38,7 @@
#include "access/transam.h"
#include "access/twophase_rmgr.h"
#include "access/xact.h"
#include "access/xlogprefetch.h"
#include "catalog/partition.h"
#include "catalog/pg_database.h"
#include "catalog/pg_proc.h"
@ -278,6 +279,7 @@ static PgStat_WalStats walStats;
static PgStat_SLRUStats slruStats[SLRU_NUM_ELEMENTS];
static PgStat_ReplSlotStats *replSlotStats;
static int nReplSlotStats;
static PgStat_RecoveryPrefetchStats recoveryPrefetchStats;
/*
* List of OIDs of databases we need to write out. If an entry is InvalidOid,
@ -349,6 +351,7 @@ static void pgstat_recv_archiver(PgStat_MsgArchiver *msg, int len);
static void pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len);
static void pgstat_recv_wal(PgStat_MsgWal *msg, int len);
static void pgstat_recv_slru(PgStat_MsgSLRU *msg, int len);
static void pgstat_recv_recoveryprefetch(PgStat_MsgRecoveryPrefetch *msg, int len);
static void pgstat_recv_funcstat(PgStat_MsgFuncstat *msg, int len);
static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
@ -1424,11 +1427,20 @@ pgstat_reset_shared_counters(const char *target)
msg.m_resettarget = RESET_BGWRITER;
else if (strcmp(target, "wal") == 0)
msg.m_resettarget = RESET_WAL;
else if (strcmp(target, "prefetch_recovery") == 0)
{
/*
* We can't ask the stats collector to do this for us as it is not
* attached to shared memory.
*/
XLogPrefetchRequestResetStats();
return;
}
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("unrecognized reset target: \"%s\"", target),
errhint("Target must be \"archiver\", \"bgwriter\" or \"wal\".")));
errhint("Target must be \"archiver\", \"bgwriter\", \"wal\" or \"prefetch_recovery\".")));
pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
pgstat_send(&msg, sizeof(msg));
@ -2873,6 +2885,22 @@ pgstat_fetch_replslot(int *nslots_p)
return replSlotStats;
}
/*
* ---------
* pgstat_fetch_recoveryprefetch() -
*
* Support function for restoring the counters managed by xlogprefetch.c.
* ---------
*/
PgStat_RecoveryPrefetchStats *
pgstat_fetch_recoveryprefetch(void)
{
backend_read_statsfile();
return &recoveryPrefetchStats;
}
/*
* Shut down a single backend's statistics reporting at process exit.
*
@ -3148,6 +3176,23 @@ pgstat_send_slru(void)
}
/* ----------
* pgstat_send_recoveryprefetch() -
*
* Send recovery prefetch statistics to the collector
* ----------
*/
void
pgstat_send_recoveryprefetch(PgStat_RecoveryPrefetchStats *stats)
{
PgStat_MsgRecoveryPrefetch msg;
pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RECOVERYPREFETCH);
msg.m_stats = *stats;
pgstat_send(&msg, sizeof(msg));
}
/* ----------
* PgstatCollectorMain() -
*
@ -3365,6 +3410,10 @@ PgstatCollectorMain(int argc, char *argv[])
pgstat_recv_slru(&msg.msg_slru, len);
break;
case PGSTAT_MTYPE_RECOVERYPREFETCH:
pgstat_recv_recoveryprefetch(&msg.msg_recoveryprefetch, len);
break;
case PGSTAT_MTYPE_FUNCSTAT:
pgstat_recv_funcstat(&msg.msg_funcstat, len);
break;
@ -3658,6 +3707,13 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
rc = fwrite(slruStats, sizeof(slruStats), 1, fpout);
(void) rc; /* we'll check for error with ferror */
/*
* Write recovery prefetch stats struct
*/
rc = fwrite(&recoveryPrefetchStats, sizeof(recoveryPrefetchStats), 1,
fpout);
(void) rc; /* we'll check for error with ferror */
/*
* Walk through the database table.
*/
@ -3933,6 +3989,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
memset(&archiverStats, 0, sizeof(archiverStats));
memset(&walStats, 0, sizeof(walStats));
memset(&slruStats, 0, sizeof(slruStats));
memset(&recoveryPrefetchStats, 0, sizeof(recoveryPrefetchStats));
/*
* Set the current timestamp (will be kept only in case we can't load an
@ -4038,6 +4095,18 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
goto done;
}
/*
* Read recoveryPrefetchStats struct
*/
if (fread(&recoveryPrefetchStats, 1, sizeof(recoveryPrefetchStats),
fpin) != sizeof(recoveryPrefetchStats))
{
ereport(pgStatRunningInCollector ? LOG : WARNING,
(errmsg("corrupted statistics file \"%s\"", statfile)));
memset(&recoveryPrefetchStats, 0, sizeof(recoveryPrefetchStats));
goto done;
}
/*
* We found an existing collector stats file. Read it and put all the
* hashtable entries into place.
@ -4356,6 +4425,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
PgStat_WalStats myWalStats;
PgStat_SLRUStats mySLRUStats[SLRU_NUM_ELEMENTS];
PgStat_ReplSlotStats myReplSlotStats;
PgStat_RecoveryPrefetchStats myRecoveryPrefetchStats;
FILE *fpin;
int32 format_id;
const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@ -4432,6 +4502,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
return false;
}
/*
* Read recovery prefetch stats struct
*/
if (fread(&myRecoveryPrefetchStats, 1, sizeof(myRecoveryPrefetchStats),
fpin) != sizeof(myRecoveryPrefetchStats))
{
ereport(pgStatRunningInCollector ? LOG : WARNING,
(errmsg("corrupted statistics file \"%s\"", statfile)));
FreeFile(fpin);
return false;
}
/* By default, we're going to return the timestamp of the global file. */
*ts = myGlobalStats.stats_timestamp;
@ -4615,6 +4697,13 @@ backend_read_statsfile(void)
if (ok && file_ts >= min_ts)
break;
/*
* If we're in crash recovery, the collector may not even be running,
* so work with what we have.
*/
if (InRecovery)
break;
/* Not there or too old, so kick the collector and wait a bit */
if ((count % PGSTAT_INQ_LOOP_COUNT) == 0)
pgstat_send_inquiry(cur_ts, min_ts, inquiry_db);
@ -5349,6 +5438,18 @@ pgstat_recv_slru(PgStat_MsgSLRU *msg, int len)
slruStats[msg->m_index].truncate += msg->m_truncate;
}
/* ----------
* pgstat_recv_recoveryprefetch() -
*
* Process a recovery prefetch message.
* ----------
*/
static void
pgstat_recv_recoveryprefetch(PgStat_MsgRecoveryPrefetch *msg, int len)
{
recoveryPrefetchStats = msg->m_stats;
}
/* ----------
* pgstat_recv_recoveryconflict() -
*

3
src/backend/storage/freespace/freespace.c
View File

@ -210,7 +210,8 @@ XLogRecordPageWithFreeSpace(RelFileNode rnode, BlockNumber heapBlk,
blkno = fsm_logical_to_physical(addr);
/* If the page doesn't exist already, extend */
buf = XLogReadBufferExtended(rnode, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR);
buf = XLogReadBufferExtended(rnode, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR,
InvalidBuffer);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);

3
src/backend/storage/ipc/ipci.c
View File

@ -22,6 +22,7 @@
#include "access/subtrans.h"
#include "access/syncscan.h"
#include "access/twophase.h"
#include "access/xlogprefetch.h"
#include "commands/async.h"
#include "miscadmin.h"
#include "pgstat.h"
@ -126,6 +127,7 @@ CreateSharedMemoryAndSemaphores(void)
size = add_size(size, PredicateLockShmemSize());
size = add_size(size, ProcGlobalShmemSize());
size = add_size(size, XLOGShmemSize());
size = add_size(size, XLogPrefetchShmemSize());
size = add_size(size, CLOGShmemSize());
size = add_size(size, CommitTsShmemSize());
size = add_size(size, SUBTRANSShmemSize());
@ -217,6 +219,7 @@ CreateSharedMemoryAndSemaphores(void)
* Set up xlog, clog, and buffers
*/
XLOGShmemInit();
XLogPrefetchShmemInit();
CLOGShmemInit();
CommitTsShmemInit();
SUBTRANSShmemInit();

51
src/backend/utils/misc/guc.c
View File

@ -41,6 +41,7 @@
#include "access/twophase.h"
#include "access/xact.h"
#include "access/xlog_internal.h"
#include "access/xlogprefetch.h"
#include "catalog/namespace.h"
#include "catalog/pg_authid.h"
#include "catalog/storage.h"
@ -209,6 +210,7 @@ static bool check_effective_io_concurrency(int *newval, void **extra, GucSource
static bool check_maintenance_io_concurrency(int *newval, void **extra, GucSource source);
static bool check_huge_page_size(int *newval, void **extra, GucSource source);
static bool check_client_connection_check_interval(int *newval, void **extra, GucSource source);
static void assign_maintenance_io_concurrency(int newval, void *extra);
static void assign_pgstat_temp_directory(const char *newval, void *extra);
static bool check_application_name(char **newval, void **extra, GucSource source);
static void assign_application_name(const char *newval, void *extra);
@ -1294,6 +1296,27 @@ static struct config_bool ConfigureNamesBool[] =
true,
NULL, NULL, NULL
},
{
{"recovery_prefetch", PGC_SIGHUP, WAL_SETTINGS,
gettext_noop("Prefetch referenced blocks during recovery"),
gettext_noop("Read ahead of the current replay position to find uncached blocks.")
},
&recovery_prefetch,
false,
NULL, assign_recovery_prefetch, NULL
},
{
{"recovery_prefetch_fpw", PGC_SIGHUP, WAL_SETTINGS,
gettext_noop("Prefetch blocks that have full page images in the WAL"),
gettext_noop("On some systems, there is no benefit to prefetching pages that will be "
"entirely overwritten, but if the logical page size of the filesystem is "
"larger than PostgreSQL's, this can be beneficial. This option has no "
"effect unless recovery_prefetch is enabled.")
},
&recovery_prefetch_fpw,
false,
NULL, assign_recovery_prefetch_fpw, NULL
},
{
{"wal_log_hints", PGC_POSTMASTER, WAL_SETTINGS,
@ -2748,6 +2771,17 @@ static struct config_int ConfigureNamesInt[] =
NULL, NULL, NULL
},
{
{"wal_decode_buffer_size", PGC_POSTMASTER, WAL_ARCHIVE_RECOVERY,
gettext_noop("Maximum buffer size for reading ahead in the WAL during recovery."),
gettext_noop("This controls the maximum distance we can read ahead n the WAL to prefetch referenced blocks."),
GUC_UNIT_BYTE
},
&wal_decode_buffer_size,
512 * 1024, 64 * 1024, INT_MAX,
NULL, NULL, NULL
},
{
{"wal_keep_size", PGC_SIGHUP, REPLICATION_SENDING,
gettext_noop("Sets the size of WAL files held for standby servers."),
@ -3068,7 +3102,8 @@ static struct config_int ConfigureNamesInt[] =
0,
#endif
0, MAX_IO_CONCURRENCY,
check_maintenance_io_concurrency, NULL, NULL
check_maintenance_io_concurrency, assign_maintenance_io_concurrency,
NULL
},
{
@ -12072,6 +12107,20 @@ check_client_connection_check_interval(int *newval, void **extra, GucSource sour
return true;
}
static void
assign_maintenance_io_concurrency(int newval, void *extra)
{
#ifdef USE_PREFETCH
/*
* Reconfigure recovery prefetching, because a setting it depends on
* changed.
*/
maintenance_io_concurrency = newval;
if (AmStartupProcess())
XLogPrefetchReconfigure();
#endif
}
static void
assign_pgstat_temp_directory(const char *newval, void *extra)
{

6
src/backend/utils/misc/postgresql.conf.sample
View File

@ -235,6 +235,12 @@
#checkpoint_flush_after = 0 # measured in pages, 0 disables
#checkpoint_warning = 30s # 0 disables
# - Prefetching during recovery -
#wal_decode_buffer_size = 512kB # lookahead window used for prefetching
#recovery_prefetch = off # prefetch pages referenced in the WAL?
#recovery_prefetch_fpw = off # even pages logged with full page?
# - Archiving -
#archive_mode = off # enables archiving; off, on, or always

1
src/include/access/xlog.h
View File

@ -132,6 +132,7 @@ extern char *PrimaryConnInfo;
extern char *PrimarySlotName;
extern bool wal_receiver_create_temp_slot;
extern bool track_wal_io_timing;
extern int wal_decode_buffer_size;
/* indirectly set via GUC system */
extern TransactionId recoveryTargetXid;

82
src/include/access/xlogprefetch.h Normal file
View File

@ -0,0 +1,82 @@
/*-------------------------------------------------------------------------
*
* xlogprefetch.h
* Declarations for the recovery prefetching module.
*
* Portions Copyright (c) 2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/include/access/xlogprefetch.h
*-------------------------------------------------------------------------
*/
#ifndef XLOGPREFETCH_H
#define XLOGPREFETCH_H
#include "access/xlogdefs.h"
/* GUCs */
extern bool recovery_prefetch;
extern bool recovery_prefetch_fpw;
struct XLogPrefetcher;
typedef struct XLogPrefetcher XLogPrefetcher;
extern int XLogPrefetchReconfigureCount;
typedef struct XLogPrefetchState
{
XLogReaderState *reader;
XLogPrefetcher *prefetcher;
int reconfigure_count;
} XLogPrefetchState;
extern size_t XLogPrefetchShmemSize(void);
extern void XLogPrefetchShmemInit(void);
extern void XLogPrefetchReconfigure(void);
extern void XLogPrefetchRequestResetStats(void);
extern void XLogPrefetchBegin(XLogPrefetchState *state, XLogReaderState *reader);
extern void XLogPrefetchEnd(XLogPrefetchState *state);
/* Functions exposed only for the use of XLogPrefetch(). */
extern XLogPrefetcher *XLogPrefetcherAllocate(XLogReaderState *reader);
extern void XLogPrefetcherFree(XLogPrefetcher *prefetcher);
extern bool XLogPrefetcherReadAhead(XLogPrefetcher *prefetch,
XLogRecPtr replaying_lsn);
/*
* Tell the prefetching module that we are now replaying a given LSN, so that
* it can decide how far ahead to read in the WAL, if configured. Return
* true if more data is needed by the reader.
*/
static inline bool
XLogPrefetch(XLogPrefetchState *state, XLogRecPtr replaying_lsn)
{
/*
* Handle any configuration changes. Rather than trying to deal with
* various parameter changes, we just tear down and set up a new
* prefetcher if anything we depend on changes.
*/
if (unlikely(state->reconfigure_count != XLogPrefetchReconfigureCount))
{
/* If we had a prefetcher, tear it down. */
if (state->prefetcher)
{
XLogPrefetcherFree(state->prefetcher);
state->prefetcher = NULL;
}
/* If we want a prefetcher, set it up. */
if (recovery_prefetch)
state->prefetcher = XLogPrefetcherAllocate(state->reader);
state->reconfigure_count = XLogPrefetchReconfigureCount;
}
if (state->prefetcher)
return XLogPrefetcherReadAhead(state->prefetcher, replaying_lsn);
return false;
}
#endif

7
src/include/access/xlogreader.h
View File

@ -39,6 +39,7 @@
#endif
#include "access/xlogrecord.h"
#include "storage/buf.h"
/* WALOpenSegment represents a WAL segment being read. */
typedef struct WALOpenSegment
@ -77,6 +78,9 @@ typedef struct
ForkNumber forknum;
BlockNumber blkno;
/* Workspace for remembering last known buffer holding this block. */
Buffer recent_buffer;
/* copy of the fork_flags field from the XLogRecordBlockHeader */
uint8 flags;
@ -397,5 +401,8 @@ extern char *XLogRecGetBlockData(XLogReaderState *record, uint8 block_id, Size *
extern bool XLogRecGetBlockTag(XLogReaderState *record, uint8 block_id,
RelFileNode *rnode, ForkNumber *forknum,
BlockNumber *blknum);
extern bool XLogRecGetRecentBuffer(XLogReaderState *record, uint8 block_id,
RelFileNode *rnode, ForkNumber *forknum,
BlockNumber *blknum, Buffer *recent_buffer);
#endif /* XLOGREADER_H */

3
src/include/access/xlogutils.h
View File

@ -42,7 +42,8 @@ extern XLogRedoAction XLogReadBufferForRedoExtended(XLogReaderState *record,
Buffer *buf);
extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
BlockNumber blkno, ReadBufferMode mode);
BlockNumber blkno, ReadBufferMode mode,
Buffer recent_buffer);
extern Relation CreateFakeRelcacheEntry(RelFileNode rnode);
extern void FreeFakeRelcacheEntry(Relation fakerel);

8
src/include/catalog/pg_proc.dat
View File

@ -6291,6 +6291,14 @@
prorettype => 'text', proargtypes => '',
prosrc => 'pg_get_wal_replay_pause_state' },
{ oid => '9085', descr => 'statistics: information about WAL prefetching',
proname => 'pg_stat_get_prefetch_recovery', prorows => '1', provolatile => 'v',
proretset => 't', prorettype => 'record', proargtypes => '',
proallargtypes => '{timestamptz,int8,int8,int8,int8,int8,int4,int4,float4,float4}',
proargmodes => '{o,o,o,o,o,o,o,o,o,o}',
proargnames => '{stats_reset,prefetch,skip_hit,skip_new,skip_fpw,skip_seq,distance,queue_depth,avg_distance,avg_queue_depth}',
prosrc => 'pg_stat_get_prefetch_recovery' },
{ oid => '2621', descr => 'reload configuration files',
proname => 'pg_reload_conf', provolatile => 'v', prorettype => 'bool',
proargtypes => '', prosrc => 'pg_reload_conf' },

26
src/include/pgstat.h
View File

@ -74,6 +74,7 @@ typedef enum StatMsgType
PGSTAT_MTYPE_BGWRITER,
PGSTAT_MTYPE_WAL,
PGSTAT_MTYPE_SLRU,
PGSTAT_MTYPE_RECOVERYPREFETCH,
PGSTAT_MTYPE_FUNCSTAT,
PGSTAT_MTYPE_FUNCPURGE,
PGSTAT_MTYPE_RECOVERYCONFLICT,
@ -197,6 +198,19 @@ typedef struct PgStat_TableXactStatus
struct PgStat_TableXactStatus *next; /* next of same subxact */
} PgStat_TableXactStatus;
/*
* Recovery prefetching statistics persisted on disk by pgstat.c, but kept in
* shared memory by xlogprefetch.c.
*/
typedef struct PgStat_RecoveryPrefetchStats
{
PgStat_Counter prefetch;
PgStat_Counter skip_hit;
PgStat_Counter skip_new;
PgStat_Counter skip_fpw;
PgStat_Counter skip_seq;
TimestampTz stat_reset_timestamp;
} PgStat_RecoveryPrefetchStats;
/* ------------------------------------------------------------
* Message formats follow
@ -536,6 +550,15 @@ typedef struct PgStat_MsgReplSlot
PgStat_Counter m_stream_bytes;
} PgStat_MsgReplSlot;
/* ----------
* PgStat_MsgRecoveryPrefetch Sent by XLogPrefetch to save statistics.
* ----------
*/
typedef struct PgStat_MsgRecoveryPrefetch
{
PgStat_MsgHdr m_hdr;
PgStat_RecoveryPrefetchStats m_stats;
} PgStat_MsgRecoveryPrefetch;
/* ----------
* PgStat_MsgRecoveryConflict Sent by the backend upon recovery conflict
@ -699,6 +722,7 @@ typedef union PgStat_Msg
PgStat_MsgBgWriter msg_bgwriter;
PgStat_MsgWal msg_wal;
PgStat_MsgSLRU msg_slru;
PgStat_MsgRecoveryPrefetch msg_recoveryprefetch;
PgStat_MsgFuncstat msg_funcstat;
PgStat_MsgFuncpurge msg_funcpurge;
PgStat_MsgRecoveryConflict msg_recoveryconflict;
@ -1088,6 +1112,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
extern void pgstat_send_archiver(const char *xlog, bool failed);
extern void pgstat_send_bgwriter(void);
extern void pgstat_send_recoveryprefetch(PgStat_RecoveryPrefetchStats *stats);
extern void pgstat_report_wal(void);
extern bool pgstat_send_wal(bool force);
@ -1104,6 +1129,7 @@ extern PgStat_GlobalStats *pgstat_fetch_global(void);
extern PgStat_WalStats *pgstat_fetch_stat_wal(void);
extern PgStat_SLRUStats *pgstat_fetch_slru(void);
extern PgStat_ReplSlotStats *pgstat_fetch_replslot(int *nslots_p);
extern PgStat_RecoveryPrefetchStats *pgstat_fetch_recoveryprefetch(void);
extern void pgstat_count_slru_page_zeroed(int slru_idx);
extern void pgstat_count_slru_page_hit(int slru_idx);

4
src/include/utils/guc.h
View File

@ -443,4 +443,8 @@ extern void assign_search_path(const char *newval, void *extra);
extern bool check_wal_buffers(int *newval, void **extra, GucSource source);
extern void assign_xlog_sync_method(int new_sync_method, void *extra);
/* in access/transam/xlogprefetch.c */
extern void assign_recovery_prefetch(bool new_value, void *extra);
extern void assign_recovery_prefetch_fpw(bool new_value, void *extra);
#endif /* GUC_H */

11
src/test/regress/expected/rules.out
View File

@ -1879,6 +1879,17 @@ pg_stat_gssapi| SELECT s.pid,
s.gss_enc AS encrypted
FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, ssl_client_dn, ssl_client_serial, ssl_issuer_dn, gss_auth, gss_princ, gss_enc, leader_pid, queryid)
WHERE (s.client_port IS NOT NULL);
pg_stat_prefetch_recovery| SELECT s.stats_reset,
s.prefetch,
s.skip_hit,
s.skip_new,
s.skip_fpw,
s.skip_seq,
s.distance,
s.queue_depth,
s.avg_distance,
s.avg_queue_depth
FROM pg_stat_get_prefetch_recovery() s(stats_reset, prefetch, skip_hit, skip_new, skip_fpw, skip_seq, distance, queue_depth, avg_distance, avg_queue_depth);
pg_stat_progress_analyze| SELECT s.pid,
s.datid,
d.datname,

4
src/tools/pgindent/typedefs.list
View File

@ -2803,6 +2803,10 @@ XLogPageHeader
XLogPageHeaderData
XLogPageReadCB
XLogPageReadPrivate
XLogPrefetcher
XLogPrefetcherFilter
XLogPrefetchState
XLogPrefetchStats
XLogReaderRoutine
XLogReaderState
XLogRecData