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Use binary search instead of brute-force scan in findNamespace().

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The previous coding presented a significant bottleneck when dumping
databases containing many thousands of schemas, since the total time
spent searching would increase roughly as O(N^2) in the number of objects.
Noted by Jeff Janes, though I rewrote his proposed patch to use the
existing findObjectByOid infrastructure.

Since this is a longstanding performance bug, backpatch to all supported
versions.
This commit is contained in:
Tom Lane 2012-05-25 14:35:37 -04:00
parent 45ca31d6a7
commit 73cc7d3b24
3 changed files with 31 additions and 23 deletions
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18
src/bin/pg_dump/common.c
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@ -48,16 +48,19 @@ static TableInfo *tblinfo;
static TypeInfo *typinfo;
static FuncInfo *funinfo;
static OprInfo *oprinfo;
static NamespaceInfo *nspinfo;
static int numTables;
static int numTypes;
static int numFuncs;
static int numOperators;
static int numCollations;
static int numNamespaces;
static DumpableObject **tblinfoindex;
static DumpableObject **typinfoindex;
static DumpableObject **funinfoindex;
static DumpableObject **oprinfoindex;
static DumpableObject **collinfoindex;
static DumpableObject **nspinfoindex;
static void flagInhTables(TableInfo *tbinfo, int numTables,
@ -81,7 +84,6 @@ getSchemaData(Archive *fout, int *numTablesPtr)
ExtensionInfo *extinfo;
InhInfo *inhinfo;
CollInfo *collinfo;
int numNamespaces;
int numExtensions;
int numAggregates;
int numInherits;
@ -101,7 +103,8 @@ getSchemaData(Archive *fout, int *numTablesPtr)
if (g_verbose)
write_msg(NULL, "reading schemas\n");
getNamespaces(fout, &numNamespaces);
nspinfo = getNamespaces(fout, &numNamespaces);
nspinfoindex = buildIndexArray(nspinfo, numNamespaces, sizeof(NamespaceInfo));
/*
* getTables should be done as soon as possible, so as to minimize the
@ -732,6 +735,17 @@ findCollationByOid(Oid oid)
return (CollInfo *) findObjectByOid(oid, collinfoindex, numCollations);
}
/*
* findNamespaceByOid
* finds the entry (in nspinfo) of the namespace with the given oid
* returns NULL if not found
*/
NamespaceInfo *
findNamespaceByOid(Oid oid)
{
return (NamespaceInfo *) findObjectByOid(oid, nspinfoindex, numNamespaces);
}
/*
* findParentsByOid

35
src/bin/pg_dump/pg_dump.c
View File

@ -129,10 +129,6 @@ char g_comment_end[10];
static const CatalogId nilCatalogId = {0, 0};
/* these are to avoid passing around info for findNamespace() */
static NamespaceInfo *g_namespaces;
static int g_numNamespaces;
/* flags for various command-line long options */
static int binary_upgrade = 0;
static int disable_dollar_quoting = 0;
@ -2595,8 +2591,7 @@ getNamespaces(Archive *fout, int *numNamespaces)
selectDumpableNamespace(&nsinfo[1]);
g_namespaces = nsinfo;
g_numNamespaces = *numNamespaces = 2;
*numNamespaces = 2;
return nsinfo;
}
@ -2648,8 +2643,7 @@ getNamespaces(Archive *fout, int *numNamespaces)
PQclear(res);
destroyPQExpBuffer(query);
g_namespaces = nsinfo;
g_numNamespaces = *numNamespaces = ntups;
*numNamespaces = ntups;
return nsinfo;
}
@ -2660,35 +2654,34 @@ getNamespaces(Archive *fout, int *numNamespaces)
* getNamespaces
*
* NB: for pre-7.3 source database, we use object OID to guess whether it's
* a system object or not. In 7.3 and later there is no guessing.
* a system object or not. In 7.3 and later there is no guessing, and we
* don't use objoid at all.
*/
static NamespaceInfo *
findNamespace(Archive *fout, Oid nsoid, Oid objoid)
{
int i;
NamespaceInfo *nsinfo;
if (fout->remoteVersion >= 70300)
{
for (i = 0; i < g_numNamespaces; i++)
{
NamespaceInfo *nsinfo = &g_namespaces[i];
if (nsoid == nsinfo->dobj.catId.oid)
return nsinfo;
}
exit_horribly(NULL, "schema with OID %u does not exist\n", nsoid);
nsinfo = findNamespaceByOid(nsoid);
}
else
{
/* This code depends on the layout set up by getNamespaces. */
/* This code depends on the dummy objects set up by getNamespaces. */
Oid i;
if (objoid > g_last_builtin_oid)
i = 0; /* user object */
else
i = 1; /* system object */
return &g_namespaces[i];
nsinfo = findNamespaceByOid(i);
}
return NULL; /* keep compiler quiet */
if (nsinfo == NULL)
exit_horribly(NULL, "schema with OID %u does not exist\n", nsoid);
return nsinfo;
}
/*

1
src/bin/pg_dump/pg_dump.h
View File

@ -511,6 +511,7 @@ extern TypeInfo *findTypeByOid(Oid oid);
extern FuncInfo *findFuncByOid(Oid oid);
extern OprInfo *findOprByOid(Oid oid);
extern CollInfo *findCollationByOid(Oid oid);
extern NamespaceInfo *findNamespaceByOid(Oid oid);
extern void simple_oid_list_append(SimpleOidList *list, Oid val);
extern void simple_string_list_append(SimpleStringList *list, const char *val);