Merge "rdbms: make selectRowCount() use $var argument to exclude NULLs"

[lhc/web/wiklou.git] / includes / libs / rdbms / database / IDatabase.php

diff --git a/includes/libs/rdbms/database/IDatabase.php b/includes/libs/rdbms/database/IDatabase.php
index 09abaa8..a5392c8 100644 (file)
--- a/includes/libs/rdbms/database/IDatabase.php
+++ b/includes/libs/rdbms/database/IDatabase.php
@@ -513,6 +513,10 @@ interface IDatabase {
         * Run an SQL query and return the result. Normally throws a DBQueryError
         * on failure. If errors are ignored, returns false instead.
         *
+        * If a connection loss is detected, then an attempt to reconnect will be made.
+        * For queries that involve no larger transactions or locks, they will be re-issued
+        * for convenience, provided the connection was re-established.
+        *
         * In new code, the query wrappers select(), insert(), update(), delete(),
         * etc. should be used where possible, since they give much better DBMS
         * independence and automatically quote or validate user input in a variety
@@ -624,6 +628,11 @@ interface IDatabase {
         * This includes the user table in the query, with the alias "a" available
         * for use in field names (e.g. a.user_name).
         *
+        * A derived table, defined by the result of selectSQLText(), requires an alias
+        * key and a Subquery instance value which wraps the SQL query, for example:
+        *
+        *    [ 'c' => new Subquery( 'SELECT ...' ) ]
+        *
         * Joins using parentheses for grouping (since MediaWiki 1.31) may be
         * constructed using nested arrays. For example,
         *
@@ -773,15 +782,15 @@ interface IDatabase {
         * doing UNION queries, where the SQL text of each query is needed. In general,
         * however, callers outside of Database classes should just use select().
         *
+        * @see IDatabase::select()
+        *
         * @param string|array $table Table name
         * @param string|array $vars Field names
         * @param string|array $conds Conditions
         * @param string $fname Caller function name
         * @param string|array $options Query options
         * @param string|array $join_conds Join conditions
-        *
-        * @return string SQL query string.
-        * @see IDatabase::select()
+        * @return string SQL query string
         */
        public function selectSQLText(
                $table, $vars, $conds = '', $fname = __METHOD__,
@@ -821,7 +830,7 @@ interface IDatabase {
         * Takes the same arguments as IDatabase::select().
         *
         * @param string $table Table name
-        * @param string $vars Unused
+        * @param string $var Column for which NULL values are not counted [default "*"]
         * @param array|string $conds Filters on the table
         * @param string $fname Function name for profiling
         * @param array $options Options for select
@@ -830,7 +839,7 @@ interface IDatabase {
         * @throws DBError
         */
        public function estimateRowCount(
-               $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+               $table, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
        );
 
        /**
@@ -843,7 +852,7 @@ interface IDatabase {
         * @since 1.27 Added $join_conds parameter
         *
         * @param array|string $tables Table names
-        * @param string $vars Unused
+        * @param string $var Column for which NULL values are not counted [default "*"]
         * @param array|string $conds Filters on the table
         * @param string $fname Function name for profiling
         * @param array $options Options for select
@@ -852,7 +861,7 @@ interface IDatabase {
         * @throws DBError
         */
        public function selectRowCount(
-               $tables, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+               $tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
        );
 
        /**
@@ -1083,6 +1092,25 @@ interface IDatabase {
         */
        public function buildIntegerCast( $field );
 
+       /**
+        * Equivalent to IDatabase::selectSQLText() except wraps the result in Subqyery
+        *
+        * @see IDatabase::selectSQLText()
+        *
+        * @param string|array $table Table name
+        * @param string|array $vars Field names
+        * @param string|array $conds Conditions
+        * @param string $fname Caller function name
+        * @param string|array $options Query options
+        * @param string|array $join_conds Join conditions
+        * @return Subquery
+        * @since 1.31
+        */
+       public function buildSelectSubquery(
+               $table, $vars, $conds = '', $fname = __METHOD__,
+               $options = [], $join_conds = []
+       );
+
        /**
         * Returns true if DBs are assumed to be on potentially different servers
         *
@@ -1400,6 +1428,8 @@ interface IDatabase {
        /**
         * Determines if the last failure was due to a deadlock
         *
+        * Note that during a deadlock, the prior transaction will have been lost
+        *
         * @return bool
         */
        public function wasDeadlock();
@@ -1407,17 +1437,21 @@ interface IDatabase {
        /**
         * Determines if the last failure was due to a lock timeout
         *
+        * Note that during a lock wait timeout, the prior transaction will have been lost
+        *
         * @return bool
         */
        public function wasLockTimeout();
 
        /**
-        * Determines if the last query error was due to a dropped connection and should
-        * be dealt with by pinging the connection and reissuing the query.
+        * Determines if the last query error was due to a dropped connection
+        *
+        * Note that during a connection loss, the prior transaction will have been lost
         *
         * @return bool
+        * @since 1.31
         */
-       public function wasErrorReissuable();
+       public function wasConnectionLoss();
 
        /**
         * Determines if the last failure was due to the database being read-only.
@@ -1426,6 +1460,15 @@ interface IDatabase {
         */
        public function wasReadOnlyError();
 
+       /**
+        * Determines if the last query error was due to something outside of the query itself
+        *
+        * Note that the transaction may have been lost, discarding prior writes and results
+        *
+        * @return bool
+        */
+       public function wasErrorReissuable();
+
        /**
         * Wait for the replica DB to catch up to a given master position
         *