upstream/postgresql
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-06-09 08:42:38 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Speed up printing of INSERT statements in pg_dump.

Browse source 
In --inserts and especially --column-inserts mode, we can get a useful
speedup by generating the common prefix of all a table's INSERT commands
just once, and then printing the prebuilt string for each row.  This avoids
multiple invocations of fmtId() and other minor fooling around.

David Rowley
This commit is contained in:
Tom Lane 2013-11-15 18:02:06 -05:00
parent 3172eea062
commit 97e1ec4670
1 changed files with 50 additions and 23 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

73
src/bin/pg_dump/pg_dump.c
View file

@ -1550,6 +1550,7 @@ dumpTableData_insert(Archive *fout, void *dcontext)
TableInfo *tbinfo = tdinfo->tdtable;
const char *classname = tbinfo->dobj.name;
PQExpBuffer q = createPQExpBuffer();
PQExpBuffer insertStmt = NULL;
PGresult *res;
int tuple;
int nfields;
@ -1591,34 +1592,57 @@ dumpTableData_insert(Archive *fout, void *dcontext)
nfields = PQnfields(res);
for (tuple = 0; tuple < PQntuples(res); tuple++)
{
archprintf(fout, "INSERT INTO %s ", fmtId(classname));
if (nfields == 0)
/*
* First time through, we build as much of the INSERT statement as
* possible in "insertStmt", which we can then just print for each
* line. If the table happens to have zero columns then this will
* be a complete statement, otherwise it will end in "VALUES(" and
* be ready to have the row's column values appended.
*/
if (insertStmt == NULL)
{
insertStmt = createPQExpBuffer();
appendPQExpBuffer(insertStmt, "INSERT INTO %s ",
fmtId(classname));
/* corner case for zero-column table */
archprintf(fout, "DEFAULT VALUES;\n");
continue;
}
if (column_inserts)
{
resetPQExpBuffer(q);
appendPQExpBuffer(q, "(");
for (field = 0; field < nfields; field++)
if (nfields == 0)
{
if (field > 0)
appendPQExpBuffer(q, ", ");
appendPQExpBufferStr(q, fmtId(PQfname(res, field)));
appendPQExpBufferStr(insertStmt, "DEFAULT VALUES;\n");
}
else
{
/* append the list of column names if required */
if (column_inserts)
{
appendPQExpBufferStr(insertStmt, "(");
for (field = 0; field < nfields; field++)
{
if (field > 0)
appendPQExpBufferStr(insertStmt, ", ");
appendPQExpBufferStr(insertStmt,
fmtId(PQfname(res, field)));
}
appendPQExpBufferStr(insertStmt, ") ");
}
appendPQExpBufferStr(insertStmt, "VALUES (");
}
appendPQExpBuffer(q, ") ");
archputs(q->data, fout);
}
archprintf(fout, "VALUES (");
archputs(insertStmt->data, fout);
/* if it is zero-column table then we're done */
if (nfields == 0)
continue;
for (field = 0; field < nfields; field++)
{
if (field > 0)
archprintf(fout, ", ");
archputs(", ", fout);
if (PQgetisnull(res, tuple, field))
{
archprintf(fout, "NULL");
archputs("NULL", fout);
continue;
}
@ -1647,7 +1671,7 @@ dumpTableData_insert(Archive *fout, void *dcontext)
const char *s = PQgetvalue(res, tuple, field);
if (strspn(s, "0123456789 +-eE.") == strlen(s))
archprintf(fout, "%s", s);
archputs(s, fout);
else
archprintf(fout, "'%s'", s);
}
@ -1661,9 +1685,9 @@ dumpTableData_insert(Archive *fout, void *dcontext)
case BOOLOID:
if (strcmp(PQgetvalue(res, tuple, field), "t") == 0)
archprintf(fout, "true");
archputs("true", fout);
else
archprintf(fout, "false");
archputs("false", fout);
break;
default:
@ -1676,7 +1700,7 @@ dumpTableData_insert(Archive *fout, void *dcontext)
break;
}
}
archprintf(fout, ");\n");
archputs(");\n", fout);
}
if (PQntuples(res) <= 0)
@ -1687,11 +1711,14 @@ dumpTableData_insert(Archive *fout, void *dcontext)
PQclear(res);
}
archprintf(fout, "\n\n");
archputs("\n\n", fout);
ExecuteSqlStatement(fout, "CLOSE _pg_dump_cursor");
destroyPQExpBuffer(q);
if (insertStmt != NULL)
destroyPQExpBuffer(insertStmt);
return 1;
}