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diff --git a/man/man1/pmlogrewrite.1 b/man/man1/pmlogrewrite.1 new file mode 100644 index 0000000..8808b42 --- /dev/null +++ b/man/man1/pmlogrewrite.1 @@ -0,0 +1,1002 @@ +'\"macro stdmacro +.\" +.\" Copyright (c) 2011 Ken McDonell. All Rights Reserved. +.\" +.\" This program is free software; you can redistribute it and/or modify it +.\" under the terms of the GNU General Public License as published by the +.\" Free Software Foundation; either version 2 of the License, or (at your +.\" option) any later version. +.\" +.\" This program is distributed in the hope that it will be useful, but +.\" WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +.\" or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +.\" for more details. +.\" +.\" +.TH PMLOGREWRITE 1 "" "Performance Co-Pilot" +.SH NAME +\f3pmlogrewrite\f1 \- rewrite Performance Co-Pilot archives +.SH SYNOPSIS +\f3$PCP_BINADM_DIR/pmlogrewrite\f1 +[\f3\-Cdiqsvw \f1] +[\f3\-c\f1 \f2config\f1] +\f2inlog\f1 [\f2outlog\f1] +.SH DESCRIPTION +.de KW +\\f(BI\\$1\\fP\\$2 +.. +.B pmlogrewrite +reads a Performance Co-Pilot (PCP) archive log +identified by +.I inlog +and creates a PCP archive log in +.IR outlog . +Under normal usage, the +.B \-c +option will be used to nominate a configuration file or files +that contains specifications (see the +.B "REWRITING RULES SYNTAX" +section below) +that describe how the data and metadata from +.I inlog +should be transformed to produce +.IR outlog . +.PP +The typical uses for +.B pmlogrewrite +would be to accommodate the evolution of Performance Metric Domain Agents +(PMDAs) where the names, metadata and semantics of metrics and their associated +instance domains may change over time, e.g. promoting the type of a metric +from a 32-bit to a 64-bit integer, or renaming a group of metrics. +Refer to the +.B EXAMPLES +section for some additional use cases. +.PP +.B pmlogrewrite +is most useful where PMDA changes, or errors in the production environment, +result in archives that cannot be combined with +.BR pmlogextract (1). +By pre-processing the archives with +.B pmlogrewrite +the resulting archives may be able to be merged with +.BR pmlogextract (1). +.PP +The input +.I inlog +must be a PCP archive log +created by +.BR pmlogger (1), +or possibly one of the tools that read and create PCP archives, e.g. +.BR pmlogextract (1) +and +.BR pmlogreduce (1). +.PP +If no +.B \-c +option is specified, then the default behavior simply creates +.I outlog +as a copy of +.IR inlog . +This is a little more complicated than +.BR cat (1), +as each PCP archive is made up of several physical files. +.PP +While +.B pmlogrewrite +may be used to repair some data consistency issues in PCP archives, +there is also a class of repair tasks that cannot be handled by +.B pmlogrewrite +and +.BR pmloglabel (1) +may be a useful tool in these cases. +.SH COMMAND LINE OPTIONS +The command line options for +.B pmlogrewrite +are as follows: +.TP 7 +.B \-C +Parse the rewriting rules and quit. +.I outlog +is not created. +When +.B \-C +is specified, this also sets +.B \-v +and +.B \-w +so that all warnings and verbose messages are displayed as +.I config +is parsed. +.TP 7 +.BI \-c " config" +If +.I config +is a file or symbolic link, +read and parse rewriting rules from there. +If +.I config +is a directory, then all of the files or symbolic links in that +directory (excluding those beginning with a period ``.'') will +be used to provide the rewriting rules. +Multiple +.B \-c +options are allowed. +.TP 7 +.B \-d +Desperate mode. Normally if a fatal error occurs, all trace of +the partially written PCP archive +.I outlog +is removed. With the +.B \-d +option, the partially created +.I outlog +archive log is not removed. +.TP 7 +.B \-i +Rather than creating +.IR outlog , +.I inlog +is rewritten in place when the +.B \-i +option is used. +A new archive is created using temporary file names and then renamed to +.I inlog +in such a way that +if any errors (not warnings) are encountered, +.I inlog +remains unaltered. +.TP 7 +.B \-q +Quick mode, where if there are no rewriting actions to be +performed (none of the global data, instance domains or metrics +from +.I inlog +will be changed), then +.B pmlogrewrite +will exit (with status 0, so success) immediately after parsing +the configuration file(s) and +.I outlog +is not created. +.TP 7 +.B \-s +When the ``units'' of a metric are changed, if the dimension in terms +of space, time and count is unaltered, then the scaling factor is being changed, +e.g. BYTE to KBYTE, or MSEC\u\s-3-1\s0\d to USEC\u\s-3-1\s0\d, or the +composite MBYTE.SEC\u\s-3-1\s0\d to KBYTE.USEC\u\s-3-1\s0\d. +The +motivation may be (a) that the original metadata was wrong but the +values in +.I inlog +are correct, or (b) the metadata is changing so the values need +to change as well. The default +.B pmlogrewrite +behaviour matches case (a). If case (b) applies, then use the +.B \-s +option and the values of all the +metrics with a scale factor change in each result will be rescaled. +For finer control over value rescaling refer to +the +.KW RESCALE +option for the +.KW UNITS +clause of the metric rewriting rule described below. +.TP 7 +.BI \-v +Increase verbosity of diagnostic output. +.TP 7 +.BI \-w +Emit warnings. Normally +.B pmlogrewrite +remains silent for any warning that is not fatal and +it is expected that for a particular archive, some (or indeed, all) +of the rewriting specifications may not apply. For example, changes to +a PMDA may be captured in a set of rewriting rules, but a single archive +may not contain all of the modified metrics nor all of the modified +instance domains and/or instances. Because these cases are expected, +they do not prevent +.B pmlogrewrite +executing, and rules that do not apply to +.I inlog +are silently ignored by default. +Similarly, some rewriting rules may involve no change because +the metadata in +.I inlog +already matches the intent of the rewriting rule to correct data +from a previous version of a PMDA. +The +.B \-w +flag forces warnings to be emitted for all of these cases. +.PP +The argument +.I outlog +is required in all cases, except when +.B \-i +is specified. +.SH REWRITING RULES SYNTAX +A configuration file +contains zero or more rewriting rules as defined below. +.PP +Keywords and special punctuation characters are shown below in +.KW bolditalic +font and are case-insensitive, so +.KW METRIC , +.KW metric +and +.KW Metric +are all equivalent in rewriting rules. +.PP +The character ``#'' introduces +a comment and the remainder of the line is ignored. Otherwise the +input is relatively free format with optional white space (spaces, tabs or +newlines) between lexical items in the rules. +.PP +A +.B global +rewriting rule has the form: +.PP +.KW GLOBAL +.KW { +.I globalspec +\&... +.KW } +.PP +where +.I globalspec +is zero or more of the following clauses: +.RS +4n +.PP +.KW HOSTNAME +.KW -> +.I hostname +.RS +4n +.PP +Modifies the label records in the +.I outlog +PCP archive, so that the metrics will appear to have +been collected from the host +.IR hostname . +.RE +.PP +.KW TIME +.KW -> +.I delta +.RS +4n +.PP +Both metric values and the instance domain metadata in a PCP +archive carry timestamps. +This clause forces all the timestamps to be adjusted by +.IR delta , +where +.I delta +is an optional sign ``+'' (the default) or ``\-'', an optional number of +hours followed by a colon ``:'', an optional number of minutes followed by a +colon ``:'', a number of seconds, an optional fraction of seconds following +a period ``.''. The simplest example would be ``30'' to increase the +timestamps by 30 seconds. A more complex example would be ``\-23:59:59.999'' +to move the timestamps backwards by one millisecond less than one day. +.RE +.PP +.KW TZ +.KW -> +\f(BI"\fP\fItimezone\fP\f(BI"\fP +.RS +4n +.PP +Modifies the label records in the +.I outlog +PCP archive, so that the metrics will appear to have been +collected from a host with a local timezone of +.IR timezone . +.I timezone +must be enclosed in quotes, and should conform to the valid +timezone syntax rules for the local platform. +.RE +.RE +.PP +An +.B indom +rewriting rule modifies an instance domain and has the form: +.PP +.KW INDOM +\fIdomain\fP\f(BI.\fP\fIserial\fP +.KW { +.I indomspec +\&... +.KW } +.PP +where +.I domain +and +.I serial +identify one or more existing instance domains from +.I inlog +\- typically +.I domain +would be an integer in the range 1 to 510 +and +.I serial +would be an integer in the range 0 to 4194304. +.PP +As a special +case +.I serial +could be an asterisk ``*'' which means the rule applies to every +instance domain with a domain number of +.IR domain . +.PP +If a designated instance domain is not in +.I inlog +the rule has no effect. +.PP +The +.I indomspec +is zero or more of the following clauses: +.RS +4n +.PP +.KW INAME +"\fIoldname\fP" +.KW -> +"\fInewname\fP" +.RS +4n +.PP +The instance identified by the external instance name +.I oldname +is renamed to +.IR newname . +Both +.I oldname +and +.I newname +must be enclosed in quotes. +.PP +As a special case, the new name may be the keyword +.KW DELETE +(with no quotes), and then the instance +.I oldname +will be expunged from +.I outlog +which removes it from the instance domain metadata and removes all +values of this instance for all the associated metrics. +.PP +If the instance names contain any embedded +spaces then special care needs to be taken in respect of the +PCP instance naming rule that treats the leading non-space +part of the instance name as the unique portion of the name for +the purposes of matching and ensuring uniqueness within an +instance domain, refer to +.BR pmdaInstance (3) +for a discussion of this issue. +.PP +As an illustration, consider the hypothetical instance domain for a metric +which contains 2 instances with the following names: +.RS +4 +.ft CW +.nf +red +eek urk +.fi +.ft P +.RE +.PP +Then some possible +.KW INAME +clauses might be: +.TP +10n +\f(CW"eek" -> "yellow like a flower"\fP +Acceptable, +.I oldname +"eek" matches the "eek urk" instance. +.TP +10n +\f(CW"red" -> "eek"\fP +Error, +.I newname +"eek" matches the existing "eek urk" +instance. +.TP +10n +\f(CW"eek urk" -> "red of another hue"\fP +Error, +.I newname +"red of another hue" matches the existing "red" +instance. +.RE +.PP +.KW INDOM +.KW -> +\fInewdomain\fP\f(BI.\fP\fInewserial\fP +.RS +4n +.PP +Modifies the metadata for the instance domain and every metric associated +with the instance domain. +As a special case, +.I newserial +could be an asterisk ``*'' which means use +.I serial +from the +.B indom +rewriting rule, although this is most useful when +.I serial +is also an asterisk. +So for example: +.RS +4n +.ft CW +indom 29.* { indom -> 109.* } +.ft P +.RE +will move all instance domains from domain 29 to domain 109. +.RE +.PP +.KW INDOM +.KW -> +.KW DUPLICATE +\fInewdomain\fP\f(BI.\fP\fInewserial\fP +.RS +4n +.PP +A special case of the previous +.KW INDOM +clause where the instance domain is a duplicate copy of the +\fIdomain\fP\f(BI.\fP\fIserial\fP instance domain from the +.I indom +rewriting rule, and then any +mapping rules are applied to the copied +\fInewdomain\fP\f(BI.\fP\fInewserial\fP instance domain. This is +useful when a PMDA is split and the same instance domain needs to +be replicated for domain \fIdomain\fP and domain \fInewdomain\fP. +So for example if the metrics +.I foo.one +and +.I foo.two +are both defined over instance domain 12.34, and +.I foo.two +is moved to another PMDA using domain 27, then the +following rewriting rules could be used: +.RS +4n +.ft CW +indom 12.34 { indom -> duplicate 27.34 } +.br +metric foo.two { indom -> 27.34 pmid -> 27.*.* } +.ft P +.RE +.RE +.PP +.KW INST +\fIoldid\fP +.KW -> +\fInewid\fP +.RS +4n +.PP +The instance identified by the internal instance identifier +.I oldid +is renumbered to +.IR newid . +Both +.I oldid +and +.I newid +are integers in the range 0 to 2\u\s-331\s0\d-1. +.PP +As a special case, +.I newid +may be the keyword +.KW DELETE +and then the instance +.I oldid +will be expunged from +.I outlog +which removes it from the instance domain metadata and removes all +values of this instance for all the associated metrics. +.RE +.RE +.PP +A +.B metric +rewriting rule has the form: +.PP +.KW METRIC +.I metricid +.KW { +.I metricspec +\&... +.KW } +.PP +where +.I metricid +identifies one or more existing metrics from +.I inlog +using either a metric name, or the internal encoding for a metric's PMID as +\fIdomain\fP\f(BI.\fP\fIcluster\fP\f(BI.\fP\fIitem\fP. +In the latter case, typically +.I domain +would be an integer in the range 1 to 510, +.I cluster +would be an integer in the range 0 to 4095, +and +.I item +would be an integer in the range 0 to 1023. +.PP +As special +cases +.I item +could be an asterisk ``*'' which means the rule applies to every +metric with a domain number of +.I domain +and a cluster number of +.IR cluster , +or +.I cluster +could be an asterisk which means the rule applies to every +metric with a domain number of +.I domain +and an item number of +.IR item , +or both +.I cluster +and +.I item +could be asterisks, and rule applies to every metric with a domain +number of +.IR domain . +.PP +If a designated metric is not in +.I inlog +the rule has no effect. +.PP +The +.I metricspec +is zero or more of the following clauses: +.RS +4n + +.PP +.KW DELETE +.RS +4n +.PP +The metric is completely removed from +.IR outlog , +both the metadata and all values in results are expunged. +.RE + +.PP +.KW INDOM +.KW -> +\fInewdomain\fP\f(BI.\fP\fInewserial\fP [ +.I pick +] +.RS +4n +.PP +Modifies the metadata to change the instance domain for this metric. +The new instance domain must exist in +.IR outlog . +.PP +The optional +.I pick +clause may be used to select one input value, or compute an aggregate +value from the instances in an input result, or assign an internal +instance identifier to a single output value. +If no +.I pick +clause is specified, the default behaviour is to copy all input values +from each input result to +an output result, however if the input instance domain is singular +(indom +.BR PM_INDOM_NULL ) +then the one output value must be assigned an internal instance +identifier, which is 0 by default, unless over-ridden by a +.KW INST +or +.KW INAME +clause as defined below. +.PP +The choices for +.I pick +are as follows: +.TP +12n +\f(BIOUTPUT FIRST\fP +choose the value of the first instance from each input result +.TP +12n +\f(BIOUTPUT LAST\fP +choose the value of the last instance from each input result +.TP +12n +\f(BIOUTPUT INST\fP \fIinstid\fP +choose the value of the instance with internal instance identifier +.I instid +from each result; the sequence of rewriting rules ensures the +.KW OUTPUT +processing happens before instance identifier renumbering +from any associated +.B indom +rule, so +.I instid +should be one of the internal instance identifiers that appears in +.I inlog +.TP +12n +\f(BIOUTPUT INAME\fP "\fIname\fP" +choose the value of the instance with +.I name +for its external instance name +from each result; the sequence of rewriting rules ensures the +.KW OUTPUT +processing happens before instance renaming +from any associated +.B indom +rule, so +.I name +should be one of the external instance names that appears in +.I inlog +.TP +12n +\f(BIOUTPUT MIN\fP +choose the smallest value in each result (metric type must be numeric +and output instance will be 0 for a non-singular instance domain) +.TP +12n +\f(BIOUTPUT MAX\fP +choose the largest value in each result (metric type must be numeric +and output instance will be 0 for a non-singular instance domain) +.TP +12n +\f(BIOUTPUT SUM\fP +choose the sum of all values in each result (metric type must be numeric +and output instance will be 0 for a non-singular instance domain) +.TP +12n +\f(BIOUTPUT AVG\fP +choose the average of all values in each result (metric type must be numeric +and output instance will be 0 for a non-singular instance domain) +.PP +If the input instance domain is singular +(indom +.BR PM_INDOM_NULL ) +then independent of any +.I pick +specifications, there is at most one value in each input result and +so +.KW FIRST , +.KW LAST , +.KW MIN , +.KW MAX , +.KW SUM +and +.KW AVG +are all equivalent and the output instance identifier will be 0. +.PP +In general it is an error to specify a rewriting action for the +same metadata or result values more than once, e.g. more than one +.KW INDOM +clause for the same instance domain. The one exception is the possible +interaction between the +.KW INDOM +clauses in the +.B indom +and +.B metric +rules. +For example the metric +.I sample.bin +is defined over the instance domain 29.2 in +.I inlog +and the following is acceptable (albeit redundant): +.RS +4n +.ft CW +.nf +indom 29.* { indom -> 109.* } +metric sample.bin { indom -> 109.2 } +.fi +.ft P +.RE +However the following is an error, because the instance domain for +.I sample.bin +has two conflicting definitions: +.RS +4n +.ft CW +.nf +indom 29.* { indom -> 109.* } +metric sample.bin { indom -> 123.2 } +.fi +.ft P +.RE +.RE + +.PP +.KW INDOM +.KW -> +.KW NULL [ +.I pick +] +.RS +4n +.PP +The metric (which must have been +previously defined over an instance domain) is being modified to +be a singular metric. This involves a metadata change and collapsing +all results for this metric so that multiple values become one value. +.PP +The optional +.I pick +part of the clause defines how the one value for each result +should be calculated and follows the same rules as described for the +non-NULL +.KW INDOM +case above. +.PP +In the absence of +.IR pick , +the default is +.KW "OUTPUT FIRST" . +.RE + +.PP +.KW NAME +.KW -> +.I newname +.RS +4n +.PP +Renames the metric in the PCP archive's metadata that supports +the Performance Metrics Name Space (PMNS). +.I newname +should not match any existing name in the archive's PMNS and must +follow the syntactic rules for valid metric names as outlined in +.BR pmns (5). +.RE + +.PP +.KW PMID +.KW -> +\fInewdomain\fP\f(BI.\fP\fInewcluster\fP\f(BI.\fP\fInewitem\fP +.RS +4n +.PP +Modifies the metadata and results to renumber the metric's PMID. +As special cases, +.I newcluster +could be an asterisk ``*'' which means use +.I cluster +from the +.B metric +rewriting rule and/or +.I item +could be an asterisk which means use +.I item +from the +.B metric +rewriting rule. +This is most useful when +.I cluster +and/or +.I item +is also an asterisk. +So for example: +.RS +4n +.ft CW +metric 30.*.* { pmid -> 123.*.* } +.ft P +.RE +will move all metrics from domain 30 to domain 123. +.RE + +.PP +.KW SEM +.KW -> +.I newsem +.RS +4n +.PP +Change the semantics of the metric. +.I newsem +should be the XXX part of the name of one of the +.B PM_SEM_XXX +macros defined in <pcp/pmapi.h> or +.BR pmLookupDesc (3), +e.g. +.KW COUNTER +for +.BR PM_TYPE_COUNTER . +.PP +No data value rewriting is performed as a result of the +.KW SEM +clause, so the usefulness +is limited to cases where a version of the associated +PMDA was exporting incorrect semantics for the metric. +.BR pmlogreduce (1) +may provide an alternative in cases where re-computation of result +values is desired. +.RE + +.PP +.KW TYPE +.KW -> +.I newtype +.RS +4n +.PP +Change the type of the metric which alters the metadata and may change the +encoding of values in results. +.I newtype +should be the XXX part of the name of one of the +.B PM_TYPE_XXX +macros defined in <pcp/pmapi.h> or +.BR pmLookupDesc (3), +e.g. +.KW FLOAT +for +.BR PM_TYPE_FLOAT . +.PP +Type conversion is only supported for cases where the old and new +metric type is numeric, so +.BR PM_TYPE_STRING , +.B PM_TYPE_AGGREGATE +and +.B PM_TYPE_EVENT +are not allowed. +Even for the numeric cases, some conversions may produce run-time errors, +e.g. integer overflow, or attempting to rewrite a negative value into +an unsigned type. +.RE + +.PP +.KW UNITS +.KW -> +.I newunits +[ +.KW RESCALE +] +.RS +4n +.PP +.I newunits +is six values separated by commas. The first 3 values describe the +dimension of the metric along the dimensions of space, time and count; these +are integer values, usually 0, 1 or \-1. The remaining 3 values describe +the scale of the metric's values in the dimensions of space, time and +count. +Space scale values should be 0 (if the space dimension is 0), else +the XXX part of the name of one of the +.B PM_SPACE_XXX +macros, e.g. +.KW KBYTE +for +.BR PM_TYPE_KBYTE . +Time scale values should be 0 (if the time dimension is 0), else +the XXX part of the name of one of the +.B PM_TIME_XXX +macros, e.g. +.KW SEC +for +.BR PM_TIME_SEC . +Count scale values should be 0 (if the time dimension is 0), else +.KW ONE +for +.BR PM_COUNT_ONE . +.PP +The +.BR PM_SPACE_XXX , +.B PM_TIME_XXX +and +.B PM_COUNT_XXX +macros are defined in <pcp/pmapi.h> or +.BR pmLookupDesc (3). +.PP +When the scale is changed (but the dimension is +unaltered) the optional keyword +.KW RESCALE +may be used to chose value rescaling as per the +.B \-s +command line option, but applied to just this metric. +.RE + +.PP +When changing the domain number for a metric or instance domain, +the new domain number will usually match an existing PMDA's domain +number. If this is not the case, then the new domain number +should not be randomly chosen; consult +.B $PCP_VAR_DIR/pmns/stdpmid +for domain numbers that are already assigned to PMDAs. +.SH EXAMPLES +.PP +To promote the values of the per-disk IOPS metrics to 64-bit to +allow aggregation over a long time period for capacity +planning, or because the PMDA has changed to export 64-bit counters +and we want to convert old archives so they can be processed +alongside new archives. +.RS +4 +.ft CW +.nf +metric disk.dev.read { type -> U64 } +metric disk.dev.write { type -> U64 } +metric disk.dev.total { type -> U64 } +.fi +.ft P +.RE +.PP +The instances associated with the load average metric +.B kernel.all.load +could be renamed and renumbered by the +rules below. +.RS +4 +.ft CW +.nf +# for the Linux PMDA, the kernel.all.load metric is defined +# over instance domain 60.2 +indom 60.2 { + inst 1 -> 60 iname "1 minute" -> "60 second" + inst 5 -> 300 iname "5 minute" -> "300 second" + inst 15 -> 900 iname "15 minute" -> "900 second" +} +.fi +.ft P +.RE +.PP +If we decide to split the ``proc'' metrics out of the Linux PMDA, this +will involve changing the domain number for the PMID of these metrics +and the associated instance domains. The rules below would rewrite an +old archive to match the changes after the PMDA split. +.RS +4 +.ft CW +.nf +# all Linux proc metrics are in 7 clusters +metric 60.8.* { pmid -> 123.*.* } +metric 60.9.* { pmid -> 123.*.* } +metric 60.13.* { pmid -> 123.*.* } +metric 60.24.* { pmid -> 123.*.* } +metric 60.31.* { pmid -> 123.*.* } +metric 60.32.* { pmid -> 123.*.* } +metric 60.51.* { pmid -> 123.*.* } +# only one instance domain for Linux proc metrics +indom 60.9 { indom -> 123.0 } +.fi +.ft P +.RE +.SH FILES +.PD 0 +For each of the +.I inlog +and +.I outlog +archive logs, several physical files are used. +.TP 10 +\f2archive\f3.meta +metadata (metric descriptions, instance domains, etc.) for the archive log +.TP +\f2archive\f3.0 +initial volume of metrics values (subsequent volumes have suffixes +.BR 1 , +.BR 2 , +\&...). +.TP +\f2archive\f3.index +temporal index to support rapid random access to the other files in the +archive log. +.PD +.SH "PCP ENVIRONMENT" +Environment variables with the prefix +.B PCP_ +are used to parameterize the file and directory names +used by PCP. +On each installation, the file +.I /etc/pcp.conf +contains the local values for these variables. +The +.B $PCP_CONF +variable may be used to specify an alternative +configuration file, +as described in +.BR pcp.conf (5). +.SH SEE ALSO +.BR PCPIntro (1), +.BR pmdaInstance (3), +.BR pmdumplog (1), +.BR pmlogger (1), +.BR pmlogextract (1), +.BR pmloglabel (1), +.BR pmlogreduce (1), +.BR pmLookupDesc (3), +.BR pmns (5), +.BR pcp.conf (5) +and +.BR pcp.env (5). +.SH DIAGNOSTICS +All error conditions detected by +.B pmlogrewrite +are reported on +.I stderr +with textual (if sometimes terse) explanation. +.PP +Should the input archive log be corrupted (this can happen +if the +.B pmlogger +instance writing the log suddenly dies), then +.B pmlogrewrite +will detect and report the position of the corruption in the file, +and any subsequent information from that archive log will not be processed. +.PP +If any error is detected, +.B pmlogrewrite +will exit with a non-zero status. |