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Commit4f1b890

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committed
Merge the various forms of transaction commit & abort records.
Since465883b two versions of commit records have existed. A compactversion that was used when no cache invalidations, smgr unlinks andsimilar were needed, and a full version that could deal with allthat. Additionally the full version was embedded into twophase commitrecords.That resulted in a measurable reduction in the size of the logged WAL insome workloads. But more recently additions like logical decoding, whiche.g. needs information about the database something was executed on,made it applicable in fewer situations. The static split generally madeit hard to expand the commit record, because concerns over the size madeit hard to add anything to the compact version.Additionally it's not particularly pretty to have twophase.c insertRM_XACT records.Rejigger things so that the commit and abort records only have one formeach, including the twophase equivalents. The presence of the variousoptional (in the sense of not being in every record) pieces is indicatedby a bits in the 'xinfo' flag. That flag previously was not included incompact commit records. To prevent an increase in size due to itspresence, it's only included if necessary; signalled by a bit in thexl_info bits available for xact.c, similar to heapam.c'sXLOG_HEAP_OPMASK/XLOG_HEAP_INIT_PAGE.Twophase commit/aborts are now the same as their normalcounterparts. The original transaction's xid is included in an optionaldata field.This means that commit records generally are smaller, except in the caseof a transaction with subtransactions, but no other special cases; theincrease there is four bytes, which seems acceptable given that the morecommon case of not having subtransactions shrank. The savings areespecially measurable for twophase commits, which previously always usedthe full version; but will in practice only infrequently have requiredthat.The motivation for this work are not the space savings and anddeduplication though; it's that it makes it easier to extend commitrecords with additional information. That's just a few lines of codenow; without impacting the common case where that information is notneeded.Discussion: 20150220152150.GD4149@awork2.anarazel.de, 235610.92468.qm%40web29004.mail.ird.yahoo.comReviewed-By: Heikki Linnakangas, Simon Riggs
1 parenta0f5954 commit4f1b890

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7 files changed

+748
-507
lines changed

7 files changed

+748
-507
lines changed

‎src/backend/access/rmgrdesc/xactdesc.c

Lines changed: 175 additions & 70 deletions
Original file line numberDiff line numberDiff line change
@@ -14,53 +14,188 @@
1414
*/
1515
#include"postgres.h"
1616

17+
#include"access/transam.h"
1718
#include"access/xact.h"
1819
#include"catalog/catalog.h"
1920
#include"storage/sinval.h"
2021
#include"utils/timestamp.h"
2122

23+
/*
24+
* Parse the WAL format of a xact commit and abort records into a easier to
25+
* understand format.
26+
*
27+
* This routines are in xactdesc.c because they're accessed in backend (when
28+
* replaying WAL) and frontend (pg_xlogdump) code. This file is the only xact
29+
* specific one shared between both. They're complicated enough that
30+
* duplication would be bothersome.
31+
*/
32+
33+
void
34+
ParseCommitRecord(uint8info,xl_xact_commit*xlrec,xl_xact_parsed_commit*parsed)
35+
{
36+
char*data= ((char*)xlrec)+MinSizeOfXactCommit;
37+
38+
memset(parsed,0,sizeof(*parsed));
39+
40+
parsed->xinfo=0;/* default, if no XLOG_XACT_HAS_INFO is present */
41+
42+
parsed->xact_time=xlrec->xact_time;
43+
44+
if (info&XLOG_XACT_HAS_INFO)
45+
{
46+
xl_xact_xinfo*xl_xinfo= (xl_xact_xinfo*)data;
47+
48+
parsed->xinfo=xl_xinfo->xinfo;
49+
50+
data+=sizeof(xl_xact_xinfo);
51+
}
52+
53+
if (parsed->xinfo&XACT_XINFO_HAS_DBINFO)
54+
{
55+
xl_xact_dbinfo*xl_dbinfo= (xl_xact_dbinfo*)data;
56+
57+
parsed->dbId=xl_dbinfo->dbId;
58+
parsed->tsId=xl_dbinfo->tsId;
59+
60+
data+=sizeof(xl_xact_dbinfo);
61+
}
62+
63+
if (parsed->xinfo&XACT_XINFO_HAS_SUBXACTS)
64+
{
65+
xl_xact_subxacts*xl_subxacts= (xl_xact_subxacts*)data;
66+
67+
parsed->nsubxacts=xl_subxacts->nsubxacts;
68+
parsed->subxacts=xl_subxacts->subxacts;
69+
70+
data+=MinSizeOfXactSubxacts;
71+
data+=parsed->nsubxacts*sizeof(TransactionId);
72+
}
73+
74+
if (parsed->xinfo&XACT_XINFO_HAS_RELFILENODES)
75+
{
76+
xl_xact_relfilenodes*xl_relfilenodes= (xl_xact_relfilenodes*)data;
77+
78+
parsed->nrels=xl_relfilenodes->nrels;
79+
parsed->xnodes=xl_relfilenodes->xnodes;
80+
81+
data+=MinSizeOfXactRelfilenodes;
82+
data+=xl_relfilenodes->nrels*sizeof(RelFileNode);
83+
}
84+
85+
if (parsed->xinfo&XACT_XINFO_HAS_INVALS)
86+
{
87+
xl_xact_invals*xl_invals= (xl_xact_invals*)data;
88+
89+
parsed->nmsgs=xl_invals->nmsgs;
90+
parsed->msgs=xl_invals->msgs;
91+
92+
data+=MinSizeOfXactInvals;
93+
data+=xl_invals->nmsgs*sizeof(SharedInvalidationMessage);
94+
}
95+
96+
if (parsed->xinfo&XACT_XINFO_HAS_TWOPHASE)
97+
{
98+
xl_xact_twophase*xl_twophase= (xl_xact_twophase*)data;
99+
100+
parsed->twophase_xid=xl_twophase->xid;
101+
102+
data+=sizeof(xl_xact_twophase);
103+
}
104+
}
105+
106+
void
107+
ParseAbortRecord(uint8info,xl_xact_abort*xlrec,xl_xact_parsed_abort*parsed)
108+
{
109+
char*data= ((char*)xlrec)+MinSizeOfXactAbort;
110+
111+
memset(parsed,0,sizeof(*parsed));
112+
113+
parsed->xinfo=0;/* default, if no XLOG_XACT_HAS_INFO is present */
114+
115+
parsed->xact_time=xlrec->xact_time;
116+
117+
if (info&XLOG_XACT_HAS_INFO)
118+
{
119+
xl_xact_xinfo*xl_xinfo= (xl_xact_xinfo*)data;
120+
121+
parsed->xinfo=xl_xinfo->xinfo;
122+
123+
data+=sizeof(xl_xact_xinfo);
124+
}
125+
126+
if (parsed->xinfo&XACT_XINFO_HAS_SUBXACTS)
127+
{
128+
xl_xact_subxacts*xl_subxacts= (xl_xact_subxacts*)data;
129+
130+
parsed->nsubxacts=xl_subxacts->nsubxacts;
131+
parsed->subxacts=xl_subxacts->subxacts;
132+
133+
data+=MinSizeOfXactSubxacts;
134+
data+=parsed->nsubxacts*sizeof(TransactionId);
135+
}
136+
137+
if (parsed->xinfo&XACT_XINFO_HAS_RELFILENODES)
138+
{
139+
xl_xact_relfilenodes*xl_relfilenodes= (xl_xact_relfilenodes*)data;
140+
141+
parsed->nrels=xl_relfilenodes->nrels;
142+
parsed->xnodes=xl_relfilenodes->xnodes;
143+
144+
data+=MinSizeOfXactRelfilenodes;
145+
data+=xl_relfilenodes->nrels*sizeof(RelFileNode);
146+
}
147+
148+
if (parsed->xinfo&XACT_XINFO_HAS_TWOPHASE)
149+
{
150+
xl_xact_twophase*xl_twophase= (xl_xact_twophase*)data;
151+
152+
parsed->twophase_xid=xl_twophase->xid;
153+
154+
data+=sizeof(xl_xact_twophase);
155+
}
156+
}
22157

23158
staticvoid
24-
xact_desc_commit(StringInfobuf,xl_xact_commit*xlrec)
159+
xact_desc_commit(StringInfobuf,uint8info,xl_xact_commit*xlrec)
25160
{
161+
xl_xact_parsed_commitparsed;
26162
inti;
27-
TransactionId*subxacts;
28163

29-
subxacts= (TransactionId*)&xlrec->xnodes[xlrec->nrels];
164+
ParseCommitRecord(info,xlrec,&parsed);
165+
166+
/* If this is a prepared xact, show the xid of the original xact */
167+
if (TransactionIdIsValid(parsed.twophase_xid))
168+
appendStringInfo(buf,"%u: ",parsed.twophase_xid);
30169

31170
appendStringInfoString(buf,timestamptz_to_str(xlrec->xact_time));
32171

33-
if (xlrec->nrels>0)
172+
if (parsed.nrels>0)
34173
{
35174
appendStringInfoString(buf,"; rels:");
36-
for (i=0;i<xlrec->nrels;i++)
175+
for (i=0;i<parsed.nrels;i++)
37176
{
38-
char*path=relpathperm(xlrec->xnodes[i],MAIN_FORKNUM);
177+
char*path=relpathperm(parsed.xnodes[i],MAIN_FORKNUM);
39178

40179
appendStringInfo(buf," %s",path);
41180
pfree(path);
42181
}
43182
}
44-
if (xlrec->nsubxacts>0)
183+
if (parsed.nsubxacts>0)
45184
{
46185
appendStringInfoString(buf,"; subxacts:");
47-
for (i=0;i<xlrec->nsubxacts;i++)
48-
appendStringInfo(buf," %u",subxacts[i]);
186+
for (i=0;i<parsed.nsubxacts;i++)
187+
appendStringInfo(buf," %u",parsed.subxacts[i]);
49188
}
50-
if (xlrec->nmsgs>0)
189+
if (parsed.nmsgs>0)
51190
{
52-
SharedInvalidationMessage*msgs;
53-
54-
msgs= (SharedInvalidationMessage*)&subxacts[xlrec->nsubxacts];
55-
56-
if (XactCompletionRelcacheInitFileInval(xlrec->xinfo))
191+
if (XactCompletionRelcacheInitFileInval(parsed.xinfo))
57192
appendStringInfo(buf,"; relcache init file inval dbid %u tsid %u",
58-
xlrec->dbId,xlrec->tsId);
193+
parsed.dbId,parsed.tsId);
59194

60195
appendStringInfoString(buf,"; inval msgs:");
61-
for (i=0;i<xlrec->nmsgs;i++)
196+
for (i=0;i<parsed.nmsgs;i++)
62197
{
63-
SharedInvalidationMessage*msg=&msgs[i];
198+
SharedInvalidationMessage*msg=&parsed.msgs[i];
64199

65200
if (msg->id >=0)
66201
appendStringInfo(buf," catcache %d",msg->id);
@@ -80,48 +215,41 @@ xact_desc_commit(StringInfo buf, xl_xact_commit *xlrec)
80215
appendStringInfo(buf," unknown id %d",msg->id);
81216
}
82217
}
218+
219+
if (XactCompletionForceSyncCommit(parsed.xinfo))
220+
appendStringInfo(buf,"; sync");
83221
}
84222

85223
staticvoid
86-
xact_desc_commit_compact(StringInfobuf,xl_xact_commit_compact*xlrec)
224+
xact_desc_abort(StringInfobuf,uint8info,xl_xact_abort*xlrec)
87225
{
226+
xl_xact_parsed_abortparsed;
88227
inti;
89228

90-
appendStringInfoString(buf,timestamptz_to_str(xlrec->xact_time));
229+
ParseAbortRecord(info,xlrec,&parsed);
91230

92-
if (xlrec->nsubxacts>0)
93-
{
94-
appendStringInfoString(buf,"; subxacts:");
95-
for (i=0;i<xlrec->nsubxacts;i++)
96-
appendStringInfo(buf," %u",xlrec->subxacts[i]);
97-
}
98-
}
99-
100-
staticvoid
101-
xact_desc_abort(StringInfobuf,xl_xact_abort*xlrec)
102-
{
103-
inti;
231+
/* If this is a prepared xact, show the xid of the original xact */
232+
if (TransactionIdIsValid(parsed.twophase_xid))
233+
appendStringInfo(buf,"%u: ",parsed.twophase_xid);
104234

105235
appendStringInfoString(buf,timestamptz_to_str(xlrec->xact_time));
106-
if (xlrec->nrels>0)
236+
if (parsed.nrels>0)
107237
{
108238
appendStringInfoString(buf,"; rels:");
109-
for (i=0;i<xlrec->nrels;i++)
239+
for (i=0;i<parsed.nrels;i++)
110240
{
111-
char*path=relpathperm(xlrec->xnodes[i],MAIN_FORKNUM);
241+
char*path=relpathperm(parsed.xnodes[i],MAIN_FORKNUM);
112242

113243
appendStringInfo(buf," %s",path);
114244
pfree(path);
115245
}
116246
}
117-
if (xlrec->nsubxacts>0)
118-
{
119-
TransactionId*xacts= (TransactionId*)
120-
&xlrec->xnodes[xlrec->nrels];
121247

248+
if (parsed.nsubxacts>0)
249+
{
122250
appendStringInfoString(buf,"; subxacts:");
123-
for (i=0;i<xlrec->nsubxacts;i++)
124-
appendStringInfo(buf," %u",xacts[i]);
251+
for (i=0;i<parsed.nsubxacts;i++)
252+
appendStringInfo(buf," %u",parsed.subxacts[i]);
125253
}
126254
}
127255

@@ -140,39 +268,19 @@ void
140268
xact_desc(StringInfobuf,XLogReaderState*record)
141269
{
142270
char*rec=XLogRecGetData(record);
143-
uint8info=XLogRecGetInfo(record)& ~XLR_INFO_MASK;
144-
145-
if (info==XLOG_XACT_COMMIT_COMPACT)
146-
{
147-
xl_xact_commit_compact*xlrec= (xl_xact_commit_compact*)rec;
271+
uint8info=XLogRecGetInfo(record)&XLOG_XACT_OPMASK;
148272

149-
xact_desc_commit_compact(buf,xlrec);
150-
}
151-
elseif (info==XLOG_XACT_COMMIT)
273+
if (info==XLOG_XACT_COMMIT||info==XLOG_XACT_COMMIT_PREPARED)
152274
{
153275
xl_xact_commit*xlrec= (xl_xact_commit*)rec;
154276

155-
xact_desc_commit(buf,xlrec);
277+
xact_desc_commit(buf,XLogRecGetInfo(record),xlrec);
156278
}
157-
elseif (info==XLOG_XACT_ABORT)
279+
elseif (info==XLOG_XACT_ABORT||info==XLOG_XACT_ABORT_PREPARED)
158280
{
159281
xl_xact_abort*xlrec= (xl_xact_abort*)rec;
160282

161-
xact_desc_abort(buf,xlrec);
162-
}
163-
elseif (info==XLOG_XACT_COMMIT_PREPARED)
164-
{
165-
xl_xact_commit_prepared*xlrec= (xl_xact_commit_prepared*)rec;
166-
167-
appendStringInfo(buf,"%u: ",xlrec->xid);
168-
xact_desc_commit(buf,&xlrec->crec);
169-
}
170-
elseif (info==XLOG_XACT_ABORT_PREPARED)
171-
{
172-
xl_xact_abort_prepared*xlrec= (xl_xact_abort_prepared*)rec;
173-
174-
appendStringInfo(buf,"%u: ",xlrec->xid);
175-
xact_desc_abort(buf,&xlrec->arec);
283+
xact_desc_abort(buf,XLogRecGetInfo(record),xlrec);
176284
}
177285
elseif (info==XLOG_XACT_ASSIGNMENT)
178286
{
@@ -193,7 +301,7 @@ xact_identify(uint8 info)
193301
{
194302
constchar*id=NULL;
195303

196-
switch (info&~XLR_INFO_MASK)
304+
switch (info&XLOG_XACT_OPMASK)
197305
{
198306
caseXLOG_XACT_COMMIT:
199307
id="COMMIT";
@@ -213,9 +321,6 @@ xact_identify(uint8 info)
213321
caseXLOG_XACT_ASSIGNMENT:
214322
id="ASSIGNMENT";
215323
break;
216-
caseXLOG_XACT_COMMIT_COMPACT:
217-
id="COMMIT_COMPACT";
218-
break;
219324
}
220325

221326
returnid;

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