pgwire: update statusReportParams to match PostgreSQL 18

Add four new ParameterStatus parameters to match PostgreSQL 18's
connection startup sequence: default_transaction_read_only,
in_hot_standby, search_path, and scram_iterations.

in_hot_standby is a read-only session variable that always returns
"off" (CockroachDB does not support hot standby). scram_iterations
is a read-only session variable whose value comes from the
server.user_login.password_hashes.default_cost.scram_sha_256
cluster setting, so it reflects the actual configured SCRAM cost.

default_transaction_read_only and search_path are also added to
bufferableParamStatusUpdates so that clients receive ParameterStatus
updates when these values change mid-session. scram_iterations is
not included because it is backed by a cluster setting rather than
session data, so the session-data-diffing mechanism cannot detect
its changes.

Also increase the SQL proxy's authentication loop iteration limit
from 20 to 30 in `authenticate()` and `readTokenAuthResult()`. The
additional ParameterStatus messages pushed the total message count
past 20 when using SCRAM-SHA-256 authentication (4 auth messages +
16 ParameterStatus + 2 finalize = 22 > 20), causing the proxy to
drop password-authenticated connections with EOF.

Fixes #126493

Release note (sql change): CockroachDB now sends
default_transaction_read_only, in_hot_standby, search_path, and
scram_iterations as ParameterStatus messages during connection
startup, matching PostgreSQL 18 behavior.

Co-Authored-By: roachdev-claude <roachdev-claude-bot@cockroachlabs.com>

Author: shghasemi

docs/generated/sql/session_vars.md

@@ -111,6 +111,7 @@ SHOW application_name;
 <tr><td><code>foreign_key_cascades_limit</code></td><td>Sets the maximum number of cascading operations for foreign key actions.</td><td><code>10000</code></td><td>No</td><td><code>sql.defaults.foreign_key_cascades_limit</code></td></tr>
 <tr><td><code>idle_in_transaction_session_timeout</code></td><td>Sets the maximum allowed duration for an idle transaction session. The session is terminated if it exceeds this limit.</td><td><code>0s</code></td><td>No</td><td><code>sql.defaults.idle_in_transaction_session_timeout</code></td></tr>
 <tr><td><code>idle_session_timeout</code></td><td>Sets the maximum allowed duration for an idle session. The session is terminated if it exceeds this limit.</td><td><code>0s</code></td><td>No</td><td><code>sql.defaults.idle_in_session_timeout</code></td></tr>
+<tr><td><code>in_hot_standby</code></td><td>Reports whether the server is currently in hot standby mode (always off in CockroachDB).</td><td><code>off</code></td><td>Yes</td><td>-</td></tr>
 <tr><td><code>index_join_streamer_batch_size</code></td><td>Sets the size limit on input rows to the ColIndexJoin operator when using the Streamer API for a single lookup KV batch.</td><td><code>8.0 MiB</code></td><td>No</td><td><code>sql.distsql.index_join_streamer.batch_size</code></td></tr>
 <tr><td><code>index_recommendations_enabled</code></td><td>Controls whether index recommendations are enabled.</td><td><code>on</code></td><td>No</td><td>-</td></tr>
 <tr><td><code>initial_retry_backoff_for_read_committed</code></td><td>Sets the initial backoff duration for automatic retries of statements in explicit READ COMMITTED transactions that encounter retry errors.</td><td><code>2ms</code></td><td>No</td><td>-</td></tr>
@@ -211,6 +212,7 @@ SHOW application_name;
 <tr><td><code>results_buffer_size</code></td><td>Specifies the size at which the pgwire results buffer will self-flush.</td><td><code>-</code></td><td>Yes</td><td>-</td></tr>
 <tr><td><code>role</code></td><td>The current role for the session.</td><td><code>none</code></td><td>No</td><td>-</td></tr>
 <tr><td><code>row_security</code></td><td>Controls whether row level security is enabled.</td><td><code>on</code></td><td>No</td><td>-</td></tr>
+<tr><td><code>scram_iterations</code></td><td>Reports the iteration count for SCRAM-SHA-256 password hashing.</td><td><code>10610</code></td><td>Yes</td><td>-</td></tr>
 <tr><td><code>search_path</code></td><td>Sets the list of namespaces to search when resolving unqualified names.</td><td><code>"$user", public</code></td><td>No</td><td>-</td></tr>
 <tr><td><code>serial_normalization</code></td><td>Controls how `SERIAL` columns are normalized.</td><td><code>rowid</code></td><td>No</td><td><code>sql.defaults.serial_normalization</code></td></tr>
 <tr><td><code>server_encoding</code></td><td>Reports the database encoding (always UTF8). This cannot be changed.</td><td><code>UTF8</code></td><td>Yes</td><td>-</td></tr>

pkg/ccl/sqlproxyccl/authentication.go

@@ -43,10 +43,12 @@ var authenticate = func(
 		return nil
 	}
 
-	// The auth step should require only a few back and forths so 20 iterations
-	// should be enough.
+	// The auth step should require only a few back and forths so 30 iterations
+	// should be enough. Note that each ParameterStatus message sent after
+	// authentication counts as one iteration, and there can be 15+ of these
+	// in addition to auth exchange messages (e.g. 4 for SCRAM-SHA-256).
 	var i int
-	for ; i < 20; i++ {
+	for ; i < 30; i++ {
 		// Read the server response and forward it to the client.
 		// TODO(spaskob): in verbose mode, log these messages.
 		backendMsg, err := be.Receive()
@@ -202,10 +204,11 @@ var readTokenAuthResult = func(conn net.Conn) (*pgproto3.BackendKeyData, error)
 	serverConn := interceptor.NewFrontendConn(conn)
 
 	var backendKeyData *pgproto3.BackendKeyData
-	// The auth step should require only a few back and forths so 20 iterations
-	// should be enough.
+	// The auth step should require only a few back and forths so 30 iterations
+	// should be enough. Note that each ParameterStatus message sent after
+	// authentication counts as one iteration.
 	var i int
-	for ; i < 20; i++ {
+	for ; i < 30; i++ {
 		backendMsg, err := serverConn.ReadMsg()
 		if err != nil {
 			return nil, withCode(

pkg/cmd/roachtest/tests/npgsql_blocklist.go

@@ -190,7 +190,6 @@ var npgsqlBlocklist = blocklist{
 	`Npgsql.Tests.FunctionTests.Param_Output`:                                                                                                       "unknown",
 	`Npgsql.Tests.FunctionTests.Resultset`:                                                                                                          "unknown",
 	`Npgsql.Tests.LargeObjectTests.Test`:                                                                                                            "unknown",
-	`Npgsql.Tests.MultipleHostsTests.Offline_state_on_query_execution_pg_non_critical_failure`:                                                      "169330",
 	`Npgsql.Tests.NestedDataReaderTests.Basic`:                                                                                                      "unknown",
 	`Npgsql.Tests.NestedDataReaderTests.Composite`:                                                                                                  "51480",
 	`Npgsql.Tests.NestedDataReaderTests.Different_field_count`:                                                                                      "unknown",

pkg/sql/exec_util.go

@@ -3552,6 +3552,8 @@ var bufferableParamStatusUpdates = func() []bufferableParamStatusUpdate {
 		"IntervalStyle",
 		"is_superuser",
 		"TimeZone",
+		"default_transaction_read_only",
+		"search_path",
 	}
 	ret := make([]bufferableParamStatusUpdate, len(params))
 	for i, param := range params {

pkg/sql/logictest/testdata/logic_test/information_schema

@@ -3950,6 +3950,7 @@ force_savepoint_restart                                          off
 foreign_key_cascades_limit                                       10000
 idle_in_transaction_session_timeout                              0
 idle_session_timeout                                             0
+in_hot_standby                                                   off
 index_join_streamer_batch_size                                   8.0 MiB
 index_recommendations_enabled                                    off
 initial_retry_backoff_for_read_committed                         2
@@ -4048,6 +4049,7 @@ require_explicit_primary_keys                                    off
 results_buffer_size                                              524288
 role                                                             none
 row_security                                                     on
+scram_iterations                                                 10610
 search_path                                                      "$user", public
 serial_normalization                                             rowid
 server_encoding                                                  UTF8

pkg/sql/logictest/testdata/logic_test/pg_catalog

@@ -3376,6 +3376,7 @@ force_savepoint_restart                                          off
 foreign_key_cascades_limit                                       10000               NULL      NULL        NULL        string
 idle_in_transaction_session_timeout                              0                   NULL      NULL        NULL        string
 idle_session_timeout                                             0                   NULL      NULL        NULL        string
+in_hot_standby                                                   off                 NULL      NULL        NULL        string
 index_join_streamer_batch_size                                   8.0 MiB             NULL      NULL        NULL        string
 index_recommendations_enabled                                    off                 NULL      NULL        NULL        string
 initial_retry_backoff_for_read_committed                         2                   NULL      NULL        NULL        string
@@ -3473,6 +3474,7 @@ require_explicit_primary_keys                                    off
 results_buffer_size                                              524288              NULL      NULL        NULL        string
 role                                                             none                NULL      NULL        NULL        string
 row_security                                                     on                  NULL      NULL        NULL        string
+scram_iterations                                                 10610               NULL      NULL        NULL        string
 search_path                                                      "$user", public     NULL      NULL        NULL        string
 serial_normalization                                             rowid               NULL      NULL        NULL        string
 server_encoding                                                  UTF8                NULL      NULL        NULL        string
@@ -3636,6 +3638,7 @@ force_savepoint_restart                                          off
 foreign_key_cascades_limit                                       10000               NULL  user     NULL      10000               10000
 idle_in_transaction_session_timeout                              0                   ms    user     NULL      0s                  0s
 idle_session_timeout                                             0                   ms    user     NULL      0s                  0s
+in_hot_standby                                                   off                 NULL  user     NULL      off                 off
 index_join_streamer_batch_size                                   8.0 MiB             B     user     NULL      8.0 MiB             8.0 MiB
 index_recommendations_enabled                                    off                 NULL  user     NULL      on                  false
 initial_retry_backoff_for_read_committed                         2                   NULL  user     NULL      2ms                 2ms
@@ -3733,6 +3736,7 @@ require_explicit_primary_keys                                    off
 results_buffer_size                                              524288              NULL  user     NULL      524288              524288
 role                                                             none                NULL  user     NULL      none                none
 row_security                                                     on                  NULL  user     NULL      on                  on
+scram_iterations                                                 10610               NULL  user     NULL      10610               10610
 search_path                                                      "$user", public     NULL  user     NULL      "$user", public     "$user", public
 serial_normalization                                             rowid               NULL  user     NULL      rowid               rowid
 server_encoding                                                  UTF8                NULL  user     NULL      UTF8                UTF8
@@ -3884,6 +3888,7 @@ force_savepoint_restart                                          NULL    NULL
 foreign_key_cascades_limit                                       NULL    NULL     NULL     NULL        NULL
 idle_in_transaction_session_timeout                              NULL    NULL     NULL     NULL        NULL
 idle_session_timeout                                             NULL    NULL     NULL     NULL        NULL
+in_hot_standby                                                   NULL    NULL     NULL     NULL        NULL
 index_join_streamer_batch_size                                   NULL    NULL     NULL     NULL        NULL
 index_recommendations_enabled                                    NULL    NULL     NULL     NULL        NULL
 initial_retry_backoff_for_read_committed                         NULL    NULL     NULL     NULL        NULL
@@ -3984,6 +3989,7 @@ require_explicit_primary_keys                                    NULL    NULL
 results_buffer_size                                              NULL    NULL     NULL     NULL        NULL
 role                                                             NULL    NULL     NULL     NULL        NULL
 row_security                                                     NULL    NULL     NULL     NULL        NULL
+scram_iterations                                                 NULL    NULL     NULL     NULL        NULL
 search_path                                                      NULL    NULL     NULL     NULL        NULL
 serial_normalization                                             NULL    NULL     NULL     NULL        NULL
 server_encoding                                                  NULL    NULL     NULL     NULL        NULL

pkg/sql/logictest/testdata/logic_test/show_source

@@ -121,6 +121,7 @@ force_savepoint_restart                                          off
 foreign_key_cascades_limit                                       10000               Sets the maximum number of cascading operations for foreign key actions.
 idle_in_transaction_session_timeout                              0                   Sets the maximum allowed duration for an idle transaction session. The session is terminated if it exceeds this limit.
 idle_session_timeout                                             0                   Sets the maximum allowed duration for an idle session. The session is terminated if it exceeds this limit.
+in_hot_standby                                                   off                 Reports whether the server is currently in hot standby mode (always off in CockroachDB).
 index_join_streamer_batch_size                                   8.0 MiB             Sets the size limit on input rows to the ColIndexJoin operator when using the Streamer API for a single lookup KV batch.
 index_recommendations_enabled                                    off                 Controls whether index recommendations are enabled.
 initial_retry_backoff_for_read_committed                         2                   Sets the initial backoff duration for automatic retries of statements in explicit READ COMMITTED transactions that encounter retry errors.
@@ -218,6 +219,7 @@ require_explicit_primary_keys                                    off
 results_buffer_size                                              524288              Specifies the size at which the pgwire results buffer will self-flush.
 role                                                             none                The current role for the session.
 row_security                                                     on                  Controls whether row level security is enabled.
+scram_iterations                                                 10610               Reports the iteration count for SCRAM-SHA-256 password hashing.
 search_path                                                      "$user", public     Sets the list of namespaces to search when resolving unqualified names.
 serial_normalization                                             rowid               Controls how `SERIAL` columns are normalized.
 server_encoding                                                  UTF8                Reports the database encoding (always UTF8). This cannot be changed.

pkg/sql/pgwire/conn.go

@@ -322,8 +322,7 @@ func (c *conn) sendInitialConnData(
 			return sql.ConnectionHandler{}, err
 		}
 	}
-	// The two following status parameters have no equivalent session
-	// variable.
+	// session_authorization has no equivalent session variable.
 	if err := c.bufferParamStatus("session_authorization", c.sessionArgs.User.Normalized()); err != nil {
 		return sql.ConnectionHandler{}, err
 	}
@@ -1485,19 +1484,23 @@ func (r *pgwireReader) ReadByte() (byte, error) {
 // initialization.
 //
 // The standard PostgreSQL status vars are listed here:
-// https://www.postgresql.org/docs/10/static/libpq-status.html
+// https://www.postgresql.org/docs/18/libpq-status.html
 var statusReportParams = []string{
 	"server_version",
 	"server_encoding",
 	"client_encoding",
 	"application_name",
-	// Note: session_authorization is handled specially in serveImpl().
+	// Note: session_authorization is handled specially in sendInitialConnData().
 	"DateStyle",
 	"IntervalStyle",
 	"is_superuser",
 	"TimeZone",
 	"integer_datetimes",
 	"standard_conforming_strings",
+	"default_transaction_read_only",
+	"search_path",
+	"scram_iterations",
+	"in_hot_standby",
 	"crdb_version", // CockroachDB extension.
 }
 

pkg/sql/session_var_descriptions.go

@@ -104,6 +104,7 @@ var sessionVarDescriptions = map[string]string{
 	"initial_retry_backoff_for_read_committed":                        "Sets the initial backoff duration for automatic retries of statements in explicit READ COMMITTED transactions that encounter retry errors.",
 	"inject_retry_errors_enabled":                                     "Causes statements (except SET) inside explicit transactions to return a transaction retry error for testing application retry logic. If the client retries using the cockroach_restart savepoint, the transaction proceeds normally after the 3rd retry error.",
 	"inject_retry_errors_on_commit_enabled":                           "Causes statements inside explicit transactions to return a retry error just before transaction commit for testing retry logic.",
+	"in_hot_standby":                                                  "Reports whether the server is currently in hot standby mode (always off in CockroachDB).",
 	"integer_datetimes":                                               "Reports whether integer datetime representation is used (always on).",
 	"internal":                                                        "Indicates whether this query came from InternalExecutor or an internal planner.",
 	"intervalstyle":                                                   "Controls the display format for `INTERVAL` values.",
@@ -185,6 +186,7 @@ var sessionVarDescriptions = map[string]string{
 	"parallelize_multi_key_lookup_joins_max_lookup_ratio":             "Sets the maximum lookup ratio threshold for parallelizing multi-key lookup joins.",
 	"parallelize_multi_key_lookup_joins_only_on_mr_mutations":         "Controls whether parallelization of multi-key lookup joins is restricted to multi-row mutations only.",
 	"password_encryption":                                             "The encryption method used for passwords.",
+	"scram_iterations":                                                "Reports the iteration count for SCRAM-SHA-256 password hashing.",
 	"pg_dump_compatibility":                                           "Controls how CockroachDB presents metadata to external tools. Valid values: off (default), postgres (suppress CRDB-specific syntax for pg_dump compatibility), cockroachdb (show CRDB syntax explicitly).",
 	"pg_trgm.similarity_threshold":                                    "Sets the value used to compare trigram similarities for the string % string overload.",
 	"plan_cache_mode":                                                 "Controls the method that the optimizer should use to choose between a custom and generic query plan.",