Hi all,
Is there a buffer size or similar optimization parameter that can be
set for QSqlDatabase PSQL connections? The docs refer to PostgreSQL
"options" without specifying what they may be.
I have a PG database cluster of about 7MB, spread over a couple dozen
tables. Locally, it takes about 6 seconds to launch my app, loading
the model data into my forms.
When I pull an identical data-set from a remote location, my
application launch time increases to over 60 seconds. Yet resource
utilization on the remote server is miniscule.
For comparison, I'm able to download the results of a 21MB SELECT
statement in less than 8 seconds via cmd-line psql. That's orders of
magnitude more data in an order of magnitude less time!
I'm creating my db connection as follows. (Sample code attached also.)
db = QtSql.QSqlDatabase.addDatabase("QPSQL")
db.setDatabaseName("fubar")
db.setHostName("localhost")
db.setUserName("admin")
db.setPassword("abc123")
Thanks in advance!
Scott
#!/usr/bin/env python
#-------------------------------------------------------------------------------
# imports
#-------------------------------------------------------------------------------
import sys, os
from PyQt4 import QtCore, QtGui, QtSql
#-------------------------------------------------------------------------------
# enum
#-------------------------------------------------------------------------------
COLOR_ID, NAME, DESCRIPTION = range(3)
#-------------------------------------------------------------------------------
# schema
#-------------------------------------------------------------------------------
def createFakeData():
query = QtSql.QSqlQuery()
print "Dropping table..."
query.exec_("DROP TABLE color")
print "Creating table..."
err1 = query.exec_("""CREATE TABLE color (
color_id INTEGER PRIMARY KEY,
name VARCHAR(20) NOT NULL,
description VARCHAR(40) NOT NULL)""")
print "Populating table..."
err2 = query.exec_("INSERT INTO color (color_id, name, description) "
"VALUES (1, 'red', 'this is red')")
query.exec_("INSERT INTO color (color_id, name, description) "
"VALUES (2, 'green', 'this is green')")
query.exec_("INSERT INTO color (color_id, name, description) "
"VALUES (3, 'blue', 'this is blue')")
#-------------------------------------------------------------------------------
# class
#-------------------------------------------------------------------------------
class QueryTestForm(QtGui.QWidget):
def __init__(self, parent=None):
QtGui.QWidget.__init__(self)
# table model
# ------------------------------------------------
self.theModel = QtSql.QSqlTableModel(self)
self.theModel.setTable("color")
self.theModel.setSort(NAME, QtCore.Qt.AscendingOrder)
self.theModel.setEditStrategy(QtSql.QSqlTableModel.OnManualSubmit)
# column headers
self.theModel.setHeaderData(COLOR_ID, QtCore.Qt.Horizontal, QtCore.QVariant("COLOR_ID"))
self.theModel.setHeaderData(NAME, QtCore.Qt.Horizontal, QtCore.QVariant("NAME"))
self.theModel.setHeaderData(DESCRIPTION, QtCore.Qt.Horizontal, QtCore.QVariant("DESCRIPTION"))
select = self.theModel.select()
# table view
# ------------------------------------------------
self.theView = QtGui.QTableView()
self.theView.setSortingEnabled(True)
self.theView.setModel(self.theModel)
self.theView.setSelectionMode(QtGui.QTableView.SingleSelection)
self.theView.setSelectionBehavior(QtGui.QTableView.SelectRows)
self.theView.setColumnHidden(COLOR_ID, True)
self.theView.resizeColumnsToContents()
self.theView.horizontalHeader().setStretchLastSection(True)
# table layout
# ------------------------------------------------
self.tableLayout = QtGui.QVBoxLayout()
self.tableLayout.addWidget(self.theView)
self.setLayout(self.tableLayout)
# table view selection model
# ------------------------------------------------
self.theSelectionModel = self.theView.selectionModel()
#-------------------------------------------------------------------------------
# main
#-------------------------------------------------------------------------------
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
db = QtSql.QSqlDatabase.addDatabase("QPSQL")
db.setDatabaseName("fubar")
db.setHostName("localhost")
db.setUserName("admin")
db.setPassword("abc123")
if not db.open():
QtGui.QMessageBox.warning(None, "Test",
QtCore.QString("Database Error: %1").arg(db.lastError().text()))
sys.exit(1)
ok = db.open()
print "db connection: ", ok
createFakeData()
form = QueryTestForm()
form.setWindowTitle("Database Test")
form.show()
sys.exit(app.exec_())
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