Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit9407dbb

Browse files
committed
Cache the results of format_type() queries in pg_dump.
There's long been a "TODO: there might be some value in cachingthe results" annotation on pg_dump's getFormattedTypeName function;but we hadn't gotten around to checking what it was costing us torepetitively look up type names. It turns out that when dumping thecurrent regression database, about 10% of the total number of queriesissued are duplicative format_type() queries. However, Hubert DepeszLubaczewski reported a not-unusual case where these account for overhalf of the queries issued by pg_dump. Individually these queriesaren't expensive, but when network lag is a factor, they add up to aproblem. We can very easily add some caching to getFormattedTypeNameto solve it.Since this is such a simple fix and can have a visible performancebenefit, back-patch to all supported branches.Discussion:https://postgr.es/m/20210826084430.GA26282@depesz.com
1 parent4090ff2 commit9407dbb

File tree

2 files changed

+15
-4
lines changed

2 files changed

+15
-4
lines changed

‎src/bin/pg_dump/pg_dump.c

Lines changed: 11 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -5206,6 +5206,7 @@ getTypes(Archive *fout, int *numTypes)
52065206
tyinfo[i].dobj.name = pg_strdup(PQgetvalue(res, i, i_typname));
52075207
tyinfo[i].dobj.namespace =
52085208
findNamespace(atooid(PQgetvalue(res, i, i_typnamespace)));
5209+
tyinfo[i].ftypname = NULL;/* may get filled later */
52095210
tyinfo[i].rolname = pg_strdup(PQgetvalue(res, i, i_rolname));
52105211
tyinfo[i].typacl = pg_strdup(PQgetvalue(res, i, i_typacl));
52115212
tyinfo[i].rtypacl = pg_strdup(PQgetvalue(res, i, i_rtypacl));
@@ -18761,12 +18762,11 @@ findDumpableDependencies(ArchiveHandle *AH, const DumpableObject *dobj,
1876118762
*
1876218763
* This does not guarantee to schema-qualify the output, so it should not
1876318764
* be used to create the target object name for CREATE or ALTER commands.
18764-
*
18765-
* TODO: there might be some value in caching the results.
1876618765
*/
1876718766
static char *
1876818767
getFormattedTypeName(Archive *fout, Oid oid, OidOptions opts)
1876918768
{
18769+
TypeInfo *typeInfo;
1877018770
char *result;
1877118771
PQExpBuffer query;
1877218772
PGresult *res;
@@ -18779,6 +18779,11 @@ getFormattedTypeName(Archive *fout, Oid oid, OidOptions opts)
1877918779
return pg_strdup("NONE");
1878018780
}
1878118781

18782+
/* see if we have the result cached in the type's TypeInfo record */
18783+
typeInfo = findTypeByOid(oid);
18784+
if (typeInfo && typeInfo->ftypname)
18785+
return pg_strdup(typeInfo->ftypname);
18786+
1878218787
query = createPQExpBuffer();
1878318788
appendPQExpBuffer(query, "SELECT pg_catalog.format_type('%u'::pg_catalog.oid, NULL)",
1878418789
oid);
@@ -18791,6 +18796,10 @@ getFormattedTypeName(Archive *fout, Oid oid, OidOptions opts)
1879118796
PQclear(res);
1879218797
destroyPQExpBuffer(query);
1879318798

18799+
/* cache a copy for later requests */
18800+
if (typeInfo)
18801+
typeInfo->ftypname = pg_strdup(result);
18802+
1879418803
return result;
1879518804
}
1879618805

‎src/bin/pg_dump/pg_dump.h

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -164,9 +164,11 @@ typedef struct _typeInfo
164164
DumpableObjectdobj;
165165

166166
/*
167-
* Note: dobj.name is the pg_type.typname entry. format_type() might
168-
* produce something different than typname
167+
* Note: dobj.name is the raw pg_type.typname entry. ftypname is the
168+
* result of format_type(), which will be quoted if needed, and might be
169+
* schema-qualified too.
169170
*/
171+
char*ftypname;
170172
char*rolname;/* name of owner, or empty string */
171173
char*typacl;
172174
char*rtypacl;

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp