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Revert "Allow on-line enabling and disabling of data checksums"
This reverts the backend sides of commit 1fde38b. I have, at least for now, left the pg_verify_checksums tool in place, as this tool can be very valuable without the rest of the patch as well, and since it's a read-only tool that only runs when the cluster is down it should be a lot safer.
1 parent 03c1179 commit a228cc1

39 files changed

+34
-1658
lines changed

‎doc/src/sgml/func.sgml

Lines changed: 0 additions & 65 deletions
Original file line numberDiff line numberDiff line change
@@ -19566,71 +19566,6 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
1956619566

1956719567
</sect2>
1956819568

19569-
<sect2 id="functions-admin-checksum">
19570-
<title>Data Checksum Functions</title>
19571-
19572-
<para>
19573-
The functions shown in <xref linkend="functions-checksums-table" /> can
19574-
be used to enable or disable data checksums in a running cluster.
19575-
See <xref linkend="checksums" /> for details.
19576-
</para>
19577-
19578-
<table id="functions-checksums-table">
19579-
<title>Checksum <acronym>SQL</acronym> Functions</title>
19580-
<tgroup cols="3">
19581-
<thead>
19582-
<row>
19583-
<entry>Function</entry>
19584-
<entry>Return Type</entry>
19585-
<entry>Description</entry>
19586-
</row>
19587-
</thead>
19588-
<tbody>
19589-
<row>
19590-
<entry>
19591-
<indexterm>
19592-
<primary>pg_enable_data_checksums</primary>
19593-
</indexterm>
19594-
<literal><function>pg_enable_data_checksums(<optional><parameter>cost_delay</parameter> <type>int</type>, <parameter>cost_limit</parameter> <type>int</type></optional>)</function></literal>
19595-
</entry>
19596-
<entry>
19597-
void
19598-
</entry>
19599-
<entry>
19600-
<para>
19601-
Initiates data checksums for the cluster. This will switch the data checksums mode
19602-
to <literal>in progress</literal> and start a background worker that will process
19603-
all data in the database and enable checksums for it. When all data pages have had
19604-
checksums enabled, the cluster will automatically switch to checksums
19605-
<literal>on</literal>.
19606-
</para>
19607-
<para>
19608-
If <parameter>cost_delay</parameter> and <parameter>cost_limit</parameter> are
19609-
specified, the speed of the process is throttled using the same principles as
19610-
<link linkend="runtime-config-resource-vacuum-cost">Cost-based Vacuum Delay</link>.
19611-
</para>
19612-
</entry>
19613-
</row>
19614-
<row>
19615-
<entry>
19616-
<indexterm>
19617-
<primary>pg_disable_data_checksums</primary>
19618-
</indexterm>
19619-
<literal><function>pg_disable_data_checksums()</function></literal>
19620-
</entry>
19621-
<entry>
19622-
void
19623-
</entry>
19624-
<entry>
19625-
Disables data checksums for the cluster.
19626-
</entry>
19627-
</row>
19628-
</tbody>
19629-
</tgroup>
19630-
</table>
19631-
19632-
</sect2>
19633-
1963419569
<sect2 id="functions-admin-dbobject">
1963519570
<title>Database Object Management Functions</title>
1963619571

‎doc/src/sgml/ref/initdb.sgml

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -214,9 +214,9 @@ PostgreSQL documentation
214214
<para>
215215
Use checksums on data pages to help detect corruption by the
216216
I/O system that would otherwise be silent. Enabling checksums
217-
may incur a noticeable performance penalty. If set, checksums
218-
are calculated for all objects, in all databases. See
219-
<xref linkend="checksums" /> for details.
217+
may incur a noticeable performance penalty. This option can only
218+
be set during initialization, and cannot be changed later. If
219+
set, checksums are calculated for all objects, in all databases.
220220
</para>
221221
</listitem>
222222
</varlistentry>

‎doc/src/sgml/reference.sgml

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@@ -284,7 +284,6 @@
284284
&pgtestfsync;
285285
&pgtesttiming;
286286
&pgupgrade;
287-
&pgVerifyChecksums;
288287
&pgwaldump;
289288
&postgres;
290289
&postmaster;

‎doc/src/sgml/wal.sgml

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Original file line numberDiff line numberDiff line change
@@ -230,87 +230,6 @@
230230
</para>
231231
</sect1>
232232

233-
<sect1 id="checksums">
234-
<title>Data checksums</title>
235-
<indexterm>
236-
<primary>checksums</primary>
237-
</indexterm>
238-
239-
<para>
240-
Data pages are not checksum protected by default, but this can optionally be enabled for a cluster.
241-
When enabled, each data page will be assigned a checksum that is updated when the page is
242-
written and verified every time the page is read. Only data pages are protected by checksums,
243-
internal data structures and temporary files are not.
244-
</para>
245-
246-
<para>
247-
Checksums are normally enabled when the cluster is initialized using
248-
<link linkend="app-initdb-data-checksums"><application>initdb</application></link>. They
249-
can also be enabled or disabled at runtime. In all cases, checksums are enabled or disabled
250-
at the full cluster level, and cannot be specified individually for databases or tables.
251-
</para>
252-
253-
<para>
254-
The current state of checksums in the cluster can be verified by viewing the value
255-
of the read-only configuration variable <xref linkend="guc-data-checksums" /> by
256-
issuing the command <command>SHOW data_checksums</command>.
257-
</para>
258-
259-
<para>
260-
When attempting to recover from corrupt data it may be necessary to bypass the checksum
261-
protection in order to recover data. To do this, temporarily set the configuration parameter
262-
<xref linkend="guc-ignore-checksum-failure" />.
263-
</para>
264-
265-
<sect2 id="checksums-enable-disable">
266-
<title>On-line enabling of checksums</title>
267-
268-
<para>
269-
Checksums can be enabled or disabled online, by calling the appropriate
270-
<link linkend="functions-admin-checksum">functions</link>.
271-
Disabling of checksums takes effect immediately when the function is called.
272-
</para>
273-
274-
<para>
275-
Enabling checksums will put the cluster in <literal>inprogress</literal> mode.
276-
During this time, checksums will be written but not verified. In addition to
277-
this, a background worker process is started that enables checksums on all
278-
existing data in the cluster. Once this worker has completed processing all
279-
databases in the cluster, the checksum mode will automatically switch to
280-
<literal>on</literal>.
281-
</para>
282-
283-
<para>
284-
The process will initially wait for all open transactions to finish before
285-
it starts, so that it can be certain that there are no tables that have been
286-
created inside a transaction that has not committed yet and thus would not
287-
be visible to the process enabling checksums. It will also, for each database,
288-
wait for all pre-existing temporary tables to get removed before it finishes.
289-
If long-lived temporary tables are used in the application it may be necessary
290-
to terminate these application connections to allow the process to complete.
291-
Information about open transactions and connections with temporary tables is
292-
written to log.
293-
</para>
294-
295-
<para>
296-
If the cluster is stopped while in <literal>inprogress</literal> mode, for
297-
any reason, then this process must be restarted manually. To do this,
298-
re-execute the function <function>pg_enable_data_checksums()</function>
299-
once the cluster has been restarted. It is not possible to resume the work,
300-
the process has to start over and re-process the cluster.
301-
</para>
302-
303-
<note>
304-
<para>
305-
Enabling checksums can cause significant I/O to the system, as most of the
306-
database pages will need to be rewritten, and will be written both to the
307-
data files and the WAL.
308-
</para>
309-
</note>
310-
311-
</sect2>
312-
</sect1>
313-
314233
<sect1 id="wal-intro">
315234
<title>Write-Ahead Logging (<acronym>WAL</acronym>)</title>
316235

‎src/backend/access/rmgrdesc/xlogdesc.c

Lines changed: 0 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -17,7 +17,6 @@
1717
#include "access/xlog.h"
1818
#include "access/xlog_internal.h"
1919
#include "catalog/pg_control.h"
20-
#include "storage/bufpage.h"
2120
#include "utils/guc.h"
2221
#include "utils/timestamp.h"
2322

@@ -138,18 +137,6 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
138137
xlrec.ThisTimeLineID, xlrec.PrevTimeLineID,
139138
timestamptz_to_str(xlrec.end_time));
140139
}
141-
else if (info == XLOG_CHECKSUMS)
142-
{
143-
xl_checksum_state xlrec;
144-
145-
memcpy(&xlrec, rec, sizeof(xl_checksum_state));
146-
if (xlrec.new_checksumtype == PG_DATA_CHECKSUM_VERSION)
147-
appendStringInfo(buf, "on");
148-
else if (xlrec.new_checksumtype == PG_DATA_CHECKSUM_INPROGRESS_VERSION)
149-
appendStringInfo(buf, "inprogress");
150-
else
151-
appendStringInfo(buf, "off");
152-
}
153140
}
154141

155142
const char *
@@ -195,9 +182,6 @@ xlog_identify(uint8 info)
195182
case XLOG_FPI_FOR_HINT:
196183
id = "FPI_FOR_HINT";
197184
break;
198-
case XLOG_CHECKSUMS:
199-
id = "CHECKSUMS";
200-
break;
201185
}
202186

203187
return id;

‎src/backend/access/transam/xlog.c

Lines changed: 6 additions & 118 deletions
Original file line numberDiff line numberDiff line change
@@ -856,7 +856,6 @@ static void SetLatestXTime(TimestampTz xtime);
856856
static void SetCurrentChunkStartTime(TimestampTz xtime);
857857
static void CheckRequiredParameterValues(void);
858858
static void XLogReportParameters(void);
859-
static void XlogChecksums(ChecksumType new_type);
860859
static void checkTimeLineSwitch(XLogRecPtr lsn, TimeLineID newTLI,
861860
TimeLineID prevTLI);
862861
static void LocalSetXLogInsertAllowed(void);
@@ -1034,7 +1033,7 @@ XLogInsertRecord(XLogRecData *rdata,
10341033
Assert(RedoRecPtr < Insert->RedoRecPtr);
10351034
RedoRecPtr = Insert->RedoRecPtr;
10361035
}
1037-
doPageWrites = (Insert->fullPageWrites || Insert->forcePageWrites || DataChecksumsInProgress());
1036+
doPageWrites = (Insert->fullPageWrites || Insert->forcePageWrites);
10381037

10391038
if (fpw_lsn != InvalidXLogRecPtr && fpw_lsn <= RedoRecPtr && doPageWrites)
10401039
{
@@ -4674,6 +4673,10 @@ ReadControlFile(void)
46744673
(SizeOfXLogLongPHD - SizeOfXLogShortPHD);
46754674

46764675
CalculateCheckpointSegments();
4676+
4677+
/* Make the initdb settings visible as GUC variables, too */
4678+
SetConfigOption("data_checksums", DataChecksumsEnabled() ? "yes" : "no",
4679+
PGC_INTERNAL, PGC_S_OVERRIDE);
46774680
}
46784681

46794682
void
@@ -4745,90 +4748,12 @@ GetMockAuthenticationNonce(void)
47454748
* Are checksums enabled for data pages?
47464749
*/
47474750
bool
4748-
DataChecksumsNeedWrite(void)
4751+
DataChecksumsEnabled(void)
47494752
{
47504753
Assert(ControlFile != NULL);
47514754
return (ControlFile->data_checksum_version > 0);
47524755
}
47534756

4754-
bool
4755-
DataChecksumsNeedVerify(void)
4756-
{
4757-
Assert(ControlFile != NULL);
4758-
4759-
/*
4760-
* Only verify checksums if they are fully enabled in the cluster. In
4761-
* inprogress state they are only updated, not verified.
4762-
*/
4763-
return (ControlFile->data_checksum_version == PG_DATA_CHECKSUM_VERSION);
4764-
}
4765-
4766-
bool
4767-
DataChecksumsInProgress(void)
4768-
{
4769-
Assert(ControlFile != NULL);
4770-
return (ControlFile->data_checksum_version == PG_DATA_CHECKSUM_INPROGRESS_VERSION);
4771-
}
4772-
4773-
void
4774-
SetDataChecksumsInProgress(void)
4775-
{
4776-
Assert(ControlFile != NULL);
4777-
if (ControlFile->data_checksum_version > 0)
4778-
return;
4779-
4780-
XlogChecksums(PG_DATA_CHECKSUM_INPROGRESS_VERSION);
4781-
4782-
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
4783-
ControlFile->data_checksum_version = PG_DATA_CHECKSUM_INPROGRESS_VERSION;
4784-
UpdateControlFile();
4785-
LWLockRelease(ControlFileLock);
4786-
}
4787-
4788-
void
4789-
SetDataChecksumsOn(void)
4790-
{
4791-
Assert(ControlFile != NULL);
4792-
4793-
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
4794-
4795-
if (ControlFile->data_checksum_version != PG_DATA_CHECKSUM_INPROGRESS_VERSION)
4796-
{
4797-
LWLockRelease(ControlFileLock);
4798-
elog(ERROR, "Checksums not in inprogress mode");
4799-
}
4800-
4801-
ControlFile->data_checksum_version = PG_DATA_CHECKSUM_VERSION;
4802-
UpdateControlFile();
4803-
LWLockRelease(ControlFileLock);
4804-
4805-
XlogChecksums(PG_DATA_CHECKSUM_VERSION);
4806-
}
4807-
4808-
void
4809-
SetDataChecksumsOff(void)
4810-
{
4811-
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
4812-
4813-
ControlFile->data_checksum_version = 0;
4814-
UpdateControlFile();
4815-
LWLockRelease(ControlFileLock);
4816-
4817-
XlogChecksums(0);
4818-
}
4819-
4820-
/* guc hook */
4821-
const char *
4822-
show_data_checksums(void)
4823-
{
4824-
if (ControlFile->data_checksum_version == PG_DATA_CHECKSUM_VERSION)
4825-
return "on";
4826-
else if (ControlFile->data_checksum_version == PG_DATA_CHECKSUM_INPROGRESS_VERSION)
4827-
return "inprogress";
4828-
else
4829-
return "off";
4830-
}
4831-
48324757
/*
48334758
* Returns a fake LSN for unlogged relations.
48344759
*
@@ -7863,16 +7788,6 @@ StartupXLOG(void)
78637788
*/
78647789
CompleteCommitTsInitialization();
78657790

7866-
/*
7867-
* If we reach this point with checksums in inprogress state, we notify
7868-
* the user that they need to manually restart the process to enable
7869-
* checksums.
7870-
*/
7871-
if (ControlFile->data_checksum_version == PG_DATA_CHECKSUM_INPROGRESS_VERSION)
7872-
ereport(WARNING,
7873-
(errmsg("checksum state is \"inprogress\" with no worker"),
7874-
errhint("Either disable or enable checksums by calling the pg_disable_data_checksums() or pg_enable_data_checksums() functions.")));
7875-
78767791
/*
78777792
* All done with end-of-recovery actions.
78787793
*
@@ -9626,22 +9541,6 @@ XLogReportParameters(void)
96269541
}
96279542
}
96289543

9629-
/*
9630-
* Log the new state of checksums
9631-
*/
9632-
static void
9633-
XlogChecksums(ChecksumType new_type)
9634-
{
9635-
xl_checksum_state xlrec;
9636-
9637-
xlrec.new_checksumtype = new_type;
9638-
9639-
XLogBeginInsert();
9640-
XLogRegisterData((char *) &xlrec, sizeof(xl_checksum_state));
9641-
9642-
XLogInsert(RM_XLOG_ID, XLOG_CHECKSUMS);
9643-
}
9644-
96459544
/*
96469545
* Update full_page_writes in shared memory, and write an
96479546
* XLOG_FPW_CHANGE record if necessary.
@@ -10070,17 +9969,6 @@ xlog_redo(XLogReaderState *record)
100709969
/* Keep track of full_page_writes */
100719970
lastFullPageWrites = fpw;
100729971
}
10073-
else if (info == XLOG_CHECKSUMS)
10074-
{
10075-
xl_checksum_state state;
10076-
10077-
memcpy(&state, XLogRecGetData(record), sizeof(xl_checksum_state));
10078-
10079-
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
10080-
ControlFile->data_checksum_version = state.new_checksumtype;
10081-
UpdateControlFile();
10082-
LWLockRelease(ControlFileLock);
10083-
}
100849972
}
100859973

100869974
#ifdef WAL_DEBUG

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