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Remove simple protocol and one round trip query options

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It is impossible to guarantee that the a query executed with the simple
protocol will behave the same as with the extended protocol. This is
because the normal pgx path relies on knowing the OID of query
parameters. Without this encoding a value can only be determined by the
value instead of the combination of value and PostgreSQL type. For
example, how should a []int32 be encoded? It might be encoded into a
PostgreSQL int4[] or json.

Removal also simplifies the core query path.

The primary reason for the simple protocol is for servers like PgBouncer
that may not be able to support normal prepared statements. After
further research it appears that issuing a "flush" instead "sync" after
preparing the unnamed statement would allow PgBouncer to work.

The one round trip mode can be better handled with prepared statements.

As a last resort, all original server functionality can still be accessed by
dropping down to PgConn.
This commit is contained in:
Jack Christensen
2019-04-13 11:39:01 -05:00
parent 5a374c467f
commit c53c9e6eb5
16 changed files with 32 additions and 1021 deletions
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stdlib/sql.go
+10 -28
View File
@@ -239,40 +239,22 @@ func (c *Conn) QueryContext(ctx context.Context, query string, argsV []driver.Na
return nil, driver.ErrBadConn
}
var rows pgx.Rows
// TODO - remove hack that creates a new prepared statement for every query -- put in place because of problem preparing empty statement name
psname := fmt.Sprintf("stdlibpx%v", &argsV)
if !c.connConfig.PreferSimpleProtocol {
// TODO - remove hack that creates a new prepared statement for every query -- put in place because of problem preparing empty statement name
psname := fmt.Sprintf("stdlibpx%v", &argsV)
ps, err := c.conn.PrepareEx(ctx, psname, query, nil)
if err != nil {
// since PrepareEx failed, we didn't actually get to send the values, so
// we can safely retry
if _, is := err.(net.Error); is {
return nil, driver.ErrBadConn
}
return nil, err
}
restrictBinaryToDatabaseSqlTypes(ps)
return c.queryPreparedContext(ctx, psname, argsV)
}
rows, err := c.conn.Query(ctx, query, namedValueToInterface(argsV)...)
ps, err := c.conn.PrepareEx(ctx, psname, query, nil)
if err != nil {
// if we got a network error before we had a chance to send the query, retry
if !c.conn.LastStmtSent() {
if _, is := err.(net.Error); is {
return nil, driver.ErrBadConn
}
// since PrepareEx failed, we didn't actually get to send the values, so
// we can safely retry
if _, is := err.(net.Error); is {
return nil, driver.ErrBadConn
}
return nil, err
}
// Preload first row because otherwise we won't know what columns are available when database/sql asks.
more := rows.Next()
return &Rows{rows: rows, skipNext: true, skipNextMore: more}, nil
restrictBinaryToDatabaseSqlTypes(ps)
return c.queryPreparedContext(ctx, psname, argsV)
}
func (c *Conn) queryPrepared(name string, argsV []driver.Value) (driver.Rows, error) {