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pgbackrest/lib/pgBackRest/Db.pm

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####################################################################################################################################
# DB MODULE
####################################################################################################################################
package pgBackRest::Db;
use strict;
use warnings FATAL => qw(all);
use Carp qw(confess);
use DBD::Pg ':async';
use DBI;
use Exporter qw(import);
our @EXPORT = qw();
use Fcntl qw(O_RDONLY);
use File::Basename qw(dirname);
use lib dirname($0);
use pgBackRest::DbVersion;
use pgBackRest::Common::Exception;
use pgBackRest::Common::Log;
use pgBackRest::Common::String;
use pgBackRest::Common::Wait;
use pgBackRest::Config::Config;
use pgBackRest::File;
use pgBackRest::Manifest;
use pgBackRest::Version;
use pgBackRest::Protocol::Common;
use pgBackRest::Protocol::Protocol;
####################################################################################################################################
# Remote operation constants
####################################################################################################################################
use constant OP_DB => 'Db';
use constant OP_DB_CONNECT => OP_DB . '->connect';
push @EXPORT, qw(OP_DB_CONNECT);
use constant OP_DB_EXECUTE_SQL => OP_DB . '->executeSql';
push @EXPORT, qw(OP_DB_EXECUTE_SQL);
use constant OP_DB_INFO => OP_DB . '->info';
push @EXPORT, qw(OP_DB_INFO);
####################################################################################################################################
# Backup advisory lock
####################################################################################################################################
use constant DB_BACKUP_ADVISORY_LOCK => '12340078987004321';
push @EXPORT, qw(DB_BACKUP_ADVISORY_LOCK);
####################################################################################################################################
# Map the control and catalog versions to PostgreSQL version.
#
# The control version can be found in src/include/catalog/pg_control.h and may not change with every version of PostgreSQL but is
# still checked to detect custom builds which change the structure. The catalog version can be found in
# src/include/catalog/catversion.h and should change with every release.
####################################################################################################################################
my $oPgControlVersionHash =
{
# iControlVersion => {iCatalogVersion => strDbVersion}
833 => {200711281 => PG_VERSION_83},
843 => {200904091 => PG_VERSION_84},
903 =>
{
201008051 => PG_VERSION_90,
201105231 => PG_VERSION_91,
},
922 => {201204301 => PG_VERSION_92},
937 => {201306121 => PG_VERSION_93},
942 =>
{
201409291 => PG_VERSION_94,
201510051 => PG_VERSION_95,
},
960 =>
{
201608131 => PG_VERSION_96,
},
};
####################################################################################################################################
# CONSTRUCTOR
####################################################################################################################################
sub new
{
my $class = shift; # Class name
# Create the class hash
my $self = {};
bless $self, $class;
# Assign function parameters, defaults, and log debug info
(
my $strOperation,
$self->{iRemoteIdx},
) =
logDebugParam
(
__PACKAGE__ . '->new', \@_,
{name => 'iRemoteIdx', required => false},
);
if (defined($self->{iRemoteIdx}))
{
$self->{strDbPath} = optionGet(optionIndex(OPTION_DB_PATH, $self->{iRemoteIdx}));
$self->{oProtocol} = protocolGet(DB, $self->{iRemoteIdx});
}
else
{
$self->{oProtocol} = protocolGet(NONE);
}
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'self', value => $self}
);
}
####################################################################################################################################
# DESTRUCTOR
####################################################################################################################################
sub DESTROY
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my ($strOperation) = logDebugParam(__PACKAGE__ . '->DESTROY');
if (defined($self->{hDb}))
{
$self->{hDb}->disconnect();
undef($self->{hDb});
}
# Return from function and log return values if any
return logDebugReturn($strOperation);
}
####################################################################################################################################
# connect
####################################################################################################################################
sub connect
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$bWarnOnError,
) =
logDebugParam
(
__PACKAGE__ . '::connect', \@_,
{name => 'bWarnOnError', default => false},
);
# Only connect if not already connected
my $bResult = true;
# Run remotely
if ($self->{oProtocol}->isRemote())
{
# Build param hash
my %oParamHash;
$oParamHash{'warn-on-error'} = $bWarnOnError;
# Execute the command
$bResult = $self->{oProtocol}->cmdExecute(OP_DB_CONNECT, \%oParamHash, false, $bWarnOnError);
if (!defined($bResult))
{
$bResult = false;
}
}
# Else run locally
else
{
if (!defined($self->{hDb}))
{
# Connect to the db
my $strDbName = 'postgres';
my $strDbUser = getpwuid($<);
my $strDbSocketPath = optionGet(optionIndex(OPTION_DB_SOCKET_PATH, $self->{iRemoteIdx}), false);
# Make sure the socket path is absolute
if (defined($strDbSocketPath) && $strDbSocketPath !~ /^\//)
{
confess &log(ERROR, "'${strDbSocketPath}' is not valid for '" . OPTION_DB_SOCKET_PATH . "' option:" .
" path must be absolute", ERROR_OPTION_INVALID_VALUE);
}
# Construct the URI
my $strDbUri = "dbi:Pg:dbname=${strDbName};port=" . optionGet(optionIndex(OPTION_DB_PORT, $self->{iRemoteIdx})) .
(defined($strDbSocketPath) ? ";host=${strDbSocketPath}" : '');
logDebugMisc
(
$strOperation, undef,
{name => 'strDbUri', value => $strDbUri},
{name => 'strDbUser', value => $strDbUser}
);
$self->{hDb} = DBI->connect($strDbUri, $strDbUser, undef,
{AutoCommit => 1, RaiseError => 0, PrintError => 0, Warn => 0});
# If db handle is not valid then check error
if (!$self->{hDb})
{
# Throw an error unless a warning was requested
if (!$bWarnOnError)
{
confess &log(ERROR, $DBI::errstr, ERROR_DB_CONNECT);
}
# Log a warning
&log(WARN, $DBI::errstr);
$bResult = false;
undef($self->{hDb});
}
}
}
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'bResult', value => $bResult}
);
}
####################################################################################################################################
# executeSql
####################################################################################################################################
sub executeSql
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$strSql,
$bIgnoreError,
$bResult,
) =
logDebugParam
(
__PACKAGE__ . '::executeSql', \@_,
{name => 'strSql'},
{name => 'bIgnoreError', default => false},
{name => 'bResult', default => true},
);
# Get the user-defined command for psql
my $strResult;
# Run remotely
if ($self->{oProtocol}->isRemote())
{
# Build param hash
my %oParamHash;
$oParamHash{'script'} = $strSql;
$oParamHash{'ignore-error'} = $bIgnoreError;
$oParamHash{'result'} = $bResult;
# Execute the command
$strResult = $self->{oProtocol}->cmdExecute(OP_DB_EXECUTE_SQL, \%oParamHash, $bResult);
}
# Else run locally
else
{
$self->connect();
# Prepare the query
my $hStatement = $self->{hDb}->prepare($strSql, {pg_async => PG_ASYNC})
or confess &log(ERROR, $DBI::errstr . ":\n${strSql}", ERROR_DB_QUERY);
# Execute the query
$hStatement->execute()
or confess &log(ERROR, $DBI::errstr. ":\n${strSql}", ERROR_DB_QUERY);
# Wait for the query to return
my $oWait = waitInit(optionGet(OPTION_DB_TIMEOUT));
my $bTimeout = true;
do
{
# Is the statement done?
if ($hStatement->pg_ready())
{
# return now if there is no result expected
if (!$bResult)
{
return;
}
if (!$hStatement->pg_result())
{
# Return if the error should be ignored
if ($bIgnoreError)
{
return '';
}
# Else report it
confess &log(ERROR, $DBI::errstr . ":\n${strSql}", ERROR_DB_QUERY);
}
# Get rows and return them
my @stryRow;
do
{
# Get next row
@stryRow = $hStatement->fetchrow_array;
# If the row has data then add it to the result
if (@stryRow)
{
# Add an LF after the first row
$strResult .= (defined($strResult) ? "\n" : '');
# Add row to result
for (my $iColumnIdx = 0; $iColumnIdx < @stryRow; $iColumnIdx++)
{
# Add tab between columns
$strResult .= $iColumnIdx == 0 ? '' : "\t";
# Add column data
$strResult .= defined($stryRow[$iColumnIdx]) ? $stryRow[$iColumnIdx] : '';
}
}
# Else check for error
elsif ($hStatement->err)
{
confess &log(ERROR, $DBI::errstr . ":\n${strSql}", ERROR_DB_QUERY);
}
}
while (@stryRow);
$bTimeout = false;
}
} while ($bTimeout && waitMore($oWait));
# If timeout then cancel the query and confess
if ($bTimeout)
{
$hStatement->pg_cancel();
confess &log(ERROR, 'statement timed out after ' . waitInterval($oWait) .
" second(s):\n${strSql}", ERROR_DB_TIMEOUT);
}
}
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strResult', value => $strResult}
);
}
####################################################################################################################################
# executeSqlRow
####################################################################################################################################
sub executeSqlRow
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$strSql
) =
logDebugParam
(
__PACKAGE__ . '->executeSqlRow', \@_,
{name => 'strSql', trace => true}
);
# Return from function and log return values if any
my @stryResult = split("\t", $self->executeSql($strSql));
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strResult', value => \@stryResult}
);
}
####################################################################################################################################
# executeSqlOne
####################################################################################################################################
sub executeSqlOne
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$strSql
) =
logDebugParam
(
__PACKAGE__ . '->executeSqlOne', \@_,
{name => 'strSql', trace => true}
);
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strResult', value => ($self->executeSqlRow($strSql))[0], trace => true}
);
}
####################################################################################################################################
# tablespaceMapGet
#
# Get the mapping between oid and tablespace name.
####################################################################################################################################
sub tablespaceMapGet
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my ($strOperation) = logDebugParam(__PACKAGE__ . '->tablespaceMapGet');
dataHashBuild(my $oTablespaceMapRef = {}, "oid\tname\n" . $self->executeSql(
'select oid, spcname from pg_tablespace'), "\t");
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'oTablespaceMapRef', value => $oTablespaceMapRef}
);
}
####################################################################################################################################
# databaseMapGet
#
# Get the mapping between oid and database name.
####################################################################################################################################
sub databaseMapGet
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my ($strOperation) = logDebugParam(__PACKAGE__ . '->databaseMapGet');
dataHashBuild(my $oDatabaseMapRef = {}, "name\t" . MANIFEST_KEY_DB_ID . "\t" . MANIFEST_KEY_DB_LAST_SYSTEM_ID . "\n" .
$self->executeSql('select datname, oid, datlastsysoid from pg_database'), "\t");
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'oDatabaseMapRef', value => $oDatabaseMapRef}
);
}
####################################################################################################################################
# info
####################################################################################################################################
sub info
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$strDbPath
) =
logDebugParam
(
__PACKAGE__ . '->info', \@_,
{name => 'strDbPath', default => $self->{strDbPath}}
);
# Get info if it is not cached
#-------------------------------------------------------------------------------------------------------------------------------
if (!defined($self->{info}{$strDbPath}))
{
# Initialize file object
my $oFile = new pgBackRest::File
(
optionGet(OPTION_STANZA),
optionGet(OPTION_REPO_PATH),
$self->{oProtocol}
);
# Get info from remote
#---------------------------------------------------------------------------------------------------------------------------
if ($oFile->isRemote(PATH_DB_ABSOLUTE))
{
# Build param hash
my %oParamHash;
$oParamHash{'db-path'} = $strDbPath;
# Output remote trace info
&log(TRACE, OP_DB_INFO . ": remote (" . $oFile->{oProtocol}->commandParamString(\%oParamHash) . ')');
# Execute the command
my $strResult = $oFile->{oProtocol}->cmdExecute(OP_DB_INFO, \%oParamHash, true);
# Split the result into return values
my @stryToken = split(/\t/, $strResult);
# Cache info so it does not need to read again for the same database
$self->{info}{$strDbPath}{strDbVersion} = $stryToken[0];
$self->{info}{$strDbPath}{iControlVersion} = $stryToken[1];
$self->{info}{$strDbPath}{iCatalogVersion} = $stryToken[2];
$self->{info}{$strDbPath}{ullDbSysId} = $stryToken[3];
}
# Get info locally
#---------------------------------------------------------------------------------------------------------------------------
else
{
# Open the control file and read system id and versions
#-----------------------------------------------------------------------------------------------------------------------
my $strControlFile = "${strDbPath}/" . DB_FILE_PGCONTROL;
my $hFile;
my $tBlock;
sysopen($hFile, $strControlFile, O_RDONLY)
or confess &log(ERROR, "unable to open ${strControlFile}", ERROR_FILE_OPEN);
# Read system identifier
sysread($hFile, $tBlock, 8) == 8
or confess &log(ERROR, "unable to read database system identifier");
$self->{info}{$strDbPath}{ullDbSysId} = unpack('Q', $tBlock);
# Read control version
sysread($hFile, $tBlock, 4) == 4
or confess &log(ERROR, "unable to read control version");
$self->{info}{$strDbPath}{iControlVersion} = unpack('L', $tBlock);
# Read catalog version
sysread($hFile, $tBlock, 4) == 4
or confess &log(ERROR, "unable to read catalog version");
$self->{info}{$strDbPath}{iCatalogVersion} = unpack('L', $tBlock);
# Close the control file
close($hFile);
# Get PostgreSQL version
$self->{info}{$strDbPath}{strDbVersion} =
$$oPgControlVersionHash{$self->{info}{$strDbPath}{iControlVersion}}{$self->{info}{$strDbPath}{iCatalogVersion}};
if (!defined($self->{info}{$strDbPath}{strDbVersion}))
{
confess &log(
ERROR,
'unexpected control version = ' . $self->{info}{$strDbPath}{iControlVersion} .
' and catalog version = ' . $self->{info}{$strDbPath}{iCatalogVersion} . "\n" .
'HINT: is this version of PostgreSQL supported?',
ERROR_VERSION_NOT_SUPPORTED);
}
}
}
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strDbVersion', value => $self->{info}{$strDbPath}{strDbVersion}},
{name => 'iControlVersion', value => $self->{info}{$strDbPath}{iControlVersion}},
{name => 'iCatalogVersion', value => $self->{info}{$strDbPath}{iCatalogVersion}},
{name => 'ullDbSysId', value => $self->{info}{$strDbPath}{ullDbSysId}}
);
}
####################################################################################################################################
# versionGet
####################################################################################################################################
sub versionGet
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my ($strOperation) = logDebugParam(__PACKAGE__ . '->versionGet');
# Get data from the cache if possible
if (defined($self->{strDbVersion}) && defined($self->{strDbPath}))
{
return $self->{strDbVersion}, $self->{strDbPath};
}
# Get version and db-path from
($self->{strDbVersion}, $self->{strDbPath}) =
$self->executeSqlRow("select (regexp_matches(split_part(version(), ' ', 2), '^[0-9]+\.[0-9]+'))[1], setting" .
" from pg_settings where name = 'data_directory'");
my @stryVersionSupport = versionSupport();
if ($self->{strDbVersion} < $stryVersionSupport[0])
{
confess &log(ERROR, 'unsupported Postgres version' . $self->{strDbVersion}, ERROR_VERSION_NOT_SUPPORTED);
}
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strDbVersion', value => $self->{strDbVersion}},
{name => 'strDbPath', value => $self->{strDbPath}}
);
}
####################################################################################################################################
# backupStart
####################################################################################################################################
sub backupStart
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$strLabel,
$bStartFast
) =
logDebugParam
(
__PACKAGE__ . '->backupStart', \@_,
{name => 'strLabel'},
{name => 'bStartFast'}
);
# Validate the database configuration
$self->configValidate($self->{strDbPath});
# Only allow start-fast option for version >= 8.4
if ($self->{strDbVersion} < PG_VERSION_84 && $bStartFast)
{
&log(WARN, OPTION_START_FAST . ' option is only available in PostgreSQL >= ' . PG_VERSION_84);
$bStartFast = false;
}
# Acquire the backup advisory lock to make sure that backups are not running from multiple backup servers against the same
# database cluster. This lock helps make the stop-auto option safe.
if (!$self->executeSqlOne('select pg_try_advisory_lock(' . DB_BACKUP_ADVISORY_LOCK . ')'))
{
confess &log(ERROR, "unable to acquire backup lock\n" .
'HINT: is another backup already running on this cluster?', ERROR_LOCK_ACQUIRE);
}
# If stop-auto is enabled check for a running backup. This feature is not supported for PostgreSQL >= 9.6 since backups are
# run in non-exclusive mode.
if (optionGet(OPTION_STOP_AUTO) && $self->{strDbVersion} < PG_VERSION_96)
{
# Running backups can only be detected in PostgreSQL >= 9.3
if ($self->{strDbVersion} >= PG_VERSION_93)
{
# If a backup is currently in progress emit a warning and then stop it
if ($self->executeSqlOne('select pg_is_in_backup()'))
{
&log(WARN, 'the cluster is already in backup mode but no backup process is running.' .
' pg_stop_backup() will be called so a new backup can be started.');
$self->backupStop();
}
}
# Else emit a warning that the feature is not supported and continue. If a backup is running then an error will be
# generated later on.
else
{
&log(WARN, OPTION_STOP_AUTO . 'option is only available in PostgreSQL >= ' . PG_VERSION_93);
}
}
# Start the backup
&log(INFO, 'execute ' . ($self->{strDbVersion} >= PG_VERSION_96 ? 'non-' : '') .
"exclusive pg_start_backup() with label \"${strLabel}\": backup begins after " .
($bStartFast ? "the requested immediate checkpoint" : "the next regular checkpoint") . " completes");
my ($strTimestampDbStart, $strArchiveStart) = $self->executeSqlRow(
"select to_char(current_timestamp, 'YYYY-MM-DD HH24:MI:SS.US TZ'), lsn::text" .
" from pg_start_backup('${strLabel}'" .
($bStartFast ? ', true' : $self->{strDbVersion} >= PG_VERSION_84 ? ', false' : '') .
($self->{strDbVersion} >= PG_VERSION_96 ? ', false' : '') . ') as lsn');
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strArchiveStart', value => $strArchiveStart},
{name => 'strTimestampDbStart', value => $strTimestampDbStart}
);
}
####################################################################################################################################
# backupStop
####################################################################################################################################
sub backupStop
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my ($strOperation) = logDebugParam(__PACKAGE__ . '->backupStop');
# Stop the backup
&log(INFO, 'execute ' . ($self->{strDbVersion} >= PG_VERSION_96 ? 'non-' : '') .
'exclusive pg_stop_backup() and wait for all WAL segments to archive');
my ($strTimestampDbStop, $strArchiveStop, $strLabel, $strTablespaceMap) =
$self->executeSqlRow(
"select to_char(clock_timestamp(), 'YYYY-MM-DD HH24:MI:SS.US TZ'), lsn::text, " .
($self->{strDbVersion} >= PG_VERSION_96 ? 'labelfile, spcmapfile' : "null as labelfile, null as spcmapfile") .
' from pg_stop_backup(' .
($self->{strDbVersion} >= PG_VERSION_96 ? 'false)' : ') as lsn'));
# Build a hash of the files that need to be written to the backup
my $oFileHash =
{
&MANIFEST_FILE_BACKUPLABEL => $strLabel,
&MANIFEST_FILE_TABLESPACEMAP => $strTablespaceMap
};
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strArchiveStop', value => $strArchiveStop},
{name => 'strTimestampDbStop', value => $strTimestampDbStop},
{name => 'oFileHash', value => $oFileHash}
);
}
####################################################################################################################################
# configValidate
#
# Validate the database configuration and archiving.
####################################################################################################################################
sub configValidate
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$strDbPath
) =
logDebugParam
(
__PACKAGE__ . '->configValidate', \@_,
{name => 'strDbPath', default => $self->{strDbPath}}
);
# Get the version from the control file
my ($strDbVersion) = $self->info($strDbPath);
# Get version and db path from the database
my ($fCompareDbVersion, $strCompareDbPath) = $self->versionGet();
# Error if the version from the control file and the configured db-path do not match the values obtained from the database
if (!($strDbVersion == $fCompareDbVersion && $strDbPath eq $strCompareDbPath))
{
confess &log(ERROR,
"version '${fCompareDbVersion}' and db-path '${strCompareDbPath}' queried from cluster does not match" .
" version '${strDbVersion}' and db-path '${strDbPath}' read from '${strDbPath}/" . DB_FILE_PGCONTROL . "'\n" .
"HINT: the db-path and db-port settings likely reference different clusters", ERROR_DB_MISMATCH);
}
# Error if archive_mode = always (support has not been added yet)
if (optionGet(OPTION_BACKUP_ARCHIVE_CHECK) && $self->executeSql('show archive_mode') eq 'always')
{
confess &log(ERROR, "archive_mode=always not supported", ERROR_FEATURE_NOT_SUPPORTED);
}
# Check if archive_command is set
if (!optionGet(OPTION_BACKUP_STANDBY) && optionGet(OPTION_BACKUP_ARCHIVE_CHECK))
{
my $strArchiveCommand = $self->executeSql('show archive_command');
if (index($strArchiveCommand, BACKREST_EXE) == -1)
{
confess &log(ERROR,
'archive_command \'${strArchiveCommand}\' must contain \'' . BACKREST_EXE . '\'', ERROR_ARCHIVE_COMMAND_INVALID);
}
}
return logDebugReturn
(
$strOperation
);
}
####################################################################################################################################
# xlogSwitch
#
# Forces a switch to the next transaction log in order to archive the current log.
####################################################################################################################################
sub xlogSwitch
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my $strOperation = logDebugParam(__PACKAGE__ . '->xlogSwitch');
# Create a restore point to ensure current xlog will be archived. For versions <= 9.0 activity will need to be generated by
# the user if there have been no writes since the last xlog switch.
if ($self->{strDbVersion} >= PG_VERSION_91)
{
$self->executeSql("select pg_create_restore_point('" . BACKREST_NAME . " Archive Check');");
}
my $strWalFileName = $self->executeSqlRow('select pg_xlogfile_name from pg_xlogfile_name(pg_switch_xlog());');
&log(INFO, "switch xlog ${strWalFileName}");
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strXlogFileName', value => $strWalFileName}
);
}
####################################################################################################################################
# replayWait
#
# Waits for replay on the standby to equal specified LSN
####################################################################################################################################
sub replayWait
{
my $self = shift;
# Assign function parameters, defaults, and log debug info
my
(
$strOperation,
$strTargetLSN,
) =
logDebugParam
(
__PACKAGE__ . '->replayWait', \@_,
{name => 'strTargetLSN'}
);
# Load ArchiveCommon Module
require pgBackRest::ArchiveCommon;
pgBackRest::ArchiveCommon->import();
# Initialize working variables
my $oWait = waitInit(optionGet(OPTION_ARCHIVE_TIMEOUT));
my $bTimeout = true;
my $strReplayedLSN = undef;
# Monitor the replay location
do
{
# Get the replay location
my $strLastReplayedLSN = $self->executeSqlOne("select coalesce(pg_last_xlog_replay_location()::text, '<NONE>')");
# Error if the replay location could not be retrieved
if ($strLastReplayedLSN eq '<NONE>')
{
confess &log(
ERROR,
"unable to query replay location on the standby using pg_last_xlog_replay_location()\n" .
"Hint: Is this a standby?",
ERROR_ARCHIVE_TIMEOUT);
}
# Is the replay lsn > target lsn? It needs to be greater because the checkpoint record is directly after the LSN returned
# by pg_start_backup().
if (lsnNormalize($strLastReplayedLSN) ge lsnNormalize($strTargetLSN))
{
$bTimeout = false;
}
else
{
# Reset the timer if the LSN is advancing
if (defined($strReplayedLSN) &&
lsnNormalize($strLastReplayedLSN) gt lsnNormalize($strReplayedLSN) &&
!waitMore($oWait))
{
$oWait = waitInit(optionGet(OPTION_ARCHIVE_TIMEOUT));
}
}
# Assigned last replayed to replayed
$strReplayedLSN = $strLastReplayedLSN;
} while ($bTimeout && waitMore($oWait));
# Error if a timeout occurred before the target lsn was reached
if ($bTimeout == true)
{
confess &log(
ERROR, "timeout before standby replayed ${strTargetLSN} - only reached ${strReplayedLSN}", ERROR_ARCHIVE_TIMEOUT);
}
# Perform a checkpoint
$self->executeSql('checkpoint', undef, false);
# On PostgreSQL >= 9.6 the checkpoint location can be verified
my $strCheckpointLSN = undef;
if ($self->{strDbVersion} >= PG_VERSION_96)
{
$strCheckpointLSN = $self->executeSqlOne('select checkpoint_location from pg_control_checkpoint()');
if (lsnNormalize($strCheckpointLSN) le lsnNormalize($strTargetLSN))
{
confess &log(
ERROR,
"the checkpoint location ${strCheckpointLSN} is less than the target location ${strTargetLSN} even though the" .
" replay location is ${strReplayedLSN}\n" .
"Hint: This should not be possible and may indicate a bug in PostgreSQL.",
ERROR_ARCHIVE_TIMEOUT);
}
}
# Return from function and log return values if any
return logDebugReturn
(
$strOperation,
{name => 'strReplayedLSN', value => $strReplayedLSN},
{name => 'strCheckpointLSN', value => $strCheckpointLSN},
);
}
1;
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