Implement support for MySQL SET parameters.

pgloader had support for PostgreSQL SET parameters (gucs) from the
beginning, and in the same vein it might be necessary to tweak MySQL
connection parameters, and allow pgloader users to control them.

See #337 and #420 where net_read_timeout and net_write_timeout might need to
be set in order to be able to complete the migration, due to high volumes of
data being processed.

pgloader.1

@@ -1805,9 +1805,14 @@ LOAD DATABASE
  WITH include drop, create tables, create indexes, reset sequences,
       workers = 8, concurrency = 1
 
-  SET maintenance_work_mem to \'128MB\',
+  SET PostgreSQL PARAMETERS
+      maintenance_work_mem to \'128MB\',
       work_mem to \'12MB\',
-      search_path to \'sakila\'
+      search_path to \'sakila, public, "$user"\'
+
+  SET MySQL PARAMETERS
+      net_read_timeout  = \'120\',
+      net_write_timeout = \'120\'
 
  CAST type datetime to timestamptz drop default drop not null using zero\-dates\-to\-null,
       type date drop not null drop default using zero\-dates\-to\-null,
@@ -2000,6 +2005,12 @@ When this option is listed pgloader only issues the \fBCOPY\fR statements, witho
 .
 .IP "" 0
 
+.
+.IP "\(bu" 4
+\fISET MySQL PARAMETERS\fR
+.
+.IP
+The \fISET MySQL PARAMETERS\fR allows setting MySQL parameters using the MySQL \fBSET\fR command each time pgloader connects to it\.
 .
 .IP "\(bu" 4
 \fICAST\fR

pgloader.1.md

@@ -1541,9 +1541,14 @@ Here's an example:
      WITH include drop, create tables, create indexes, reset sequences,
           workers = 8, concurrency = 1
 
-      SET maintenance_work_mem to '128MB',
+      SET PostgreSQL PARAMETERS
+          maintenance_work_mem to '128MB',
           work_mem to '12MB',
-          search_path to 'sakila'
+          search_path to 'sakila, public, "$user"'
+    
+      SET MySQL PARAMETERS
+          net_read_timeout  = '120',
+          net_write_timeout = '120'
 
      CAST type datetime to timestamptz drop default drop not null using zero-dates-to-null,
           type date drop not null drop default using zero-dates-to-null,
@@ -1742,6 +1747,11 @@ The `database` command accepts the following clauses and options:
 	    When this option is listed pgloader only issues the `COPY`
 	    statements, without doing any other processing.
 
+  - *SET MySQL PARAMETERS*
+  
+    The *SET MySQL PARAMETERS* allows setting MySQL parameters using the
+    MySQL `SET` command each time pgloader connects to it.
+  
   - *CAST*
 
 	The cast clause allows to specify custom casting rules, either to

src/params.lisp

@@ -24,6 +24,7 @@
            #:*copy-batch-size*
            #:*concurrent-batches*
 	   #:*pg-settings*
+           #:*mysql-settings*
 	   #:*default-tmpdir*
 	   #:init-params-from-environment
 	   #:getenv-default
@@ -136,6 +137,7 @@
   "How many batches do we stack in the queue in advance.")
 
 (defparameter *pg-settings* nil "An alist of GUC names and values.")
+(defparameter *mysql-settings* nil "An alist of GUC names and values.")
 
 ;;;
 ;;; Archive processing: downloads and unzip.

src/parsers/command-keywords.lisp

@@ -51,6 +51,7 @@
   (def-keyword-rule "on")
   (def-keyword-rule "error")
   (def-keyword-rule "stop")
+  (def-keyword-rule "parameters")
   ;; option for loading from a file
   (def-keyword-rule "workers")
   (def-keyword-rule "batch")
@@ -145,3 +146,5 @@
 (defrule kw-auto-increment (and "auto_increment" (* (or #\Tab #\Space)))
   (:constant :auto-increment))
 
+(defrule kw-postgresql (or (~ "pgsql") (~ "postgresql")))
+(defrule kw-mysql (~ "mysql"))

src/parsers/command-mysql.lisp

@@ -61,11 +61,19 @@
   (:lambda (tables)
     (cons :decoding tables)))
 
+
+;;;
+;;; MySQL SET parameters, because sometimes we need that
+;;;
+(defrule mysql-gucs (and kw-set kw-mysql kw-parameters generic-option-list)
+  (:lambda (mygucs) (cons :mysql-gucs (fourth mygucs))))
+
 
 ;;;
 ;;; Allow clauses to appear in any order
 ;;;
 (defrule load-mysql-optional-clauses (* (or mysql-options
+                                            mysql-gucs
                                             gucs
                                             casts
                                             alter-table
@@ -140,7 +148,8 @@
 
 (defun lisp-code-for-loading-from-mysql (my-db-conn pg-db-conn
                                          &key
-                                           gucs casts views before after options
+                                           gucs mysql-gucs
+                                           casts views before after options
                                            alter-table alter-schema
                                            ((:including incl))
                                            ((:excluding excl))
@@ -149,6 +158,7 @@
      (let* ((*default-cast-rules* ',*mysql-default-cast-rules*)
             (*cast-rules*         ',casts)
             (*decoding-as*        ',decoding-as)
+            (*mysql-settings*     ',mysql-gucs)
             ,@(pgsql-connection-bindings pg-db-conn gucs)
             ,@(batch-control-bindings options)
             ,@(identifier-case-binding options)
@@ -175,7 +185,7 @@
     (destructuring-bind (my-db-uri
                          pg-db-uri
                          &key
-                         gucs casts views before after options
+                         gucs mysql-gucs casts views before after options
                          alter-table alter-schema
                          including excluding decoding)
         source
@@ -184,6 +194,7 @@
             (t
              (lisp-code-for-loading-from-mysql my-db-uri pg-db-uri
                                                :gucs gucs
+                                               :mysql-gucs mysql-gucs
                                                :casts casts
                                                :views views
                                                :before before

src/parsers/command-options.lisp

@@ -208,7 +208,9 @@
       ;; here we want an alist
       (list* opt1 opts))))
 
-(defrule gucs (and kw-set generic-option-list)
+(defrule gucs (and kw-set
+                   (? (and kw-postgresql kw-parameters))
+                   generic-option-list)
   (:lambda (source)
-    (bind (((_ gucs) source))
+    (bind (((_ _ gucs) source))
       (cons :gucs gucs))))

src/sources/mysql/mysql-schema.lisp

@@ -29,6 +29,11 @@
                                  :password (db-pass myconn)
                                  :database (db-name myconn))))
   (log-message :debug "CONNECTED TO ~a" myconn)
+
+  ;; apply mysql-settings, if any
+  (loop :for (name . value) :in *mysql-settings*
+     :for sql := (format nil "set ~a = ~a;" name value)
+     :do (query myconn sql))
   ;; return the connection object
   myconn)
 
@@ -47,7 +52,7 @@
                     (as-text t)
                     (result-type 'list))
   "Run SQL query against MySQL connection MYCONN."
-  (log-message :debug "MySQL: sending query: ~a" sql)
+  (log-message :sql "MySQL: sending query: ~a" sql)
   (qmynd:mysql-query (conn-handle myconn)
                      sql
                      :row-fn row-fn
@@ -57,14 +62,14 @@
 ;;;
 ;;; The generic API query is recent, used to look like this:
 ;;;
+(declaim (inline mysql-query))
 (defun mysql-query (query &key row-fn (as-text t) (result-type 'list))
   "Execute given QUERY within the current *connection*, and set proper
    defaults for pgloader."
-  (log-message :sql "MySQL: sending query: ~a" query)
-  (qmynd:mysql-query (conn-handle *connection*) query
-                     :row-fn row-fn
-                     :as-text as-text
-                     :result-type result-type))
+  (query *connection* query
+         :row-fn row-fn
+         :as-text as-text
+         :result-type result-type))
 
 ;;;
 ;;; Function for accessing the MySQL catalogs, implementing auto-discovery.

src/utils/threads.lisp

@@ -12,6 +12,7 @@
                             (*copy-batch-size*    . ,*copy-batch-size*)
                             (*concurrent-batches* . ,*concurrent-batches*)
 			    (*pg-settings*        . ',*pg-settings*)
+			    (*mysql-settings*     . ',*mysql-settings*)
                             (*root-dir*           . ,*root-dir*)
                             (*fd-path-root*       . ,*fd-path-root*)
                             (*client-min-messages* . ,*client-min-messages*)

test/sakila.load

@@ -11,10 +11,15 @@ load database
       max parallel create index = 4-- ,
       -- quote identifiers
 
-  SET maintenance_work_mem to '128MB',
+  SET PostgreSQL PARAMETERS
+      maintenance_work_mem to '128MB',
       work_mem to '12MB',
       search_path to 'sakila, public, "$user"'
 
+  SET MySQL PARAMETERS
+      net_read_timeout  = '120',
+      net_write_timeout = '120'
+
  CAST type date drop not null drop default using zero-dates-to-null,
       type datetime to timestamp drop default drop not null using zero-dates-to-null