From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Sun, 15 Sep 2019 18:39:07 +0000 (+0300)
Subject: lib-sql: Try to reuse prepared statements if possible
X-Git-Tag: 2.3.9~151
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0ffab9312e601f964721c174d355d5ceb30be152;p=thirdparty%2Fdovecot%2Fcore.git

lib-sql: Try to reuse prepared statements if possible
---

diff --git a/src/lib-sql/driver-cassandra.c b/src/lib-sql/driver-cassandra.c
index 1976dd27f1..daddaeca3c 100644
--- a/src/lib-sql/driver-cassandra.c
+++ b/src/lib-sql/driver-cassandra.c
@@ -2048,6 +2048,7 @@ driver_cassandra_prepared_statement_init(struct sql_db *db,
 	struct cassandra_sql_prepared_statement *prep_stmt =
 		i_new(struct cassandra_sql_prepared_statement, 1);
 	prep_stmt->prep_stmt.db = db;
+	prep_stmt->prep_stmt.refcount = 1;
 	prep_stmt->prep_stmt.query_template = i_strdup(query_template);
 	i_array_init(&prep_stmt->pending_statements, 4);
 	prepare_start(prep_stmt);
diff --git a/src/lib-sql/sql-api-private.h b/src/lib-sql/sql-api-private.h
index 022c5e9e39..f8b91c1818 100644
--- a/src/lib-sql/sql-api-private.h
+++ b/src/lib-sql/sql-api-private.h
@@ -135,6 +135,7 @@ struct sql_db {
 	void *state_change_context;
 
 	struct event *event;
+	HASH_TABLE(char *, struct sql_prepared_statement *) prepared_stmt_hash;
 
 	enum sql_db_state state;
 	/* last time we started connecting to this server
@@ -178,6 +179,7 @@ struct sql_result_vfuncs {
 
 struct sql_prepared_statement {
 	struct sql_db *db;
+	int refcount;
 	char *query_template;
 };
 
diff --git a/src/lib-sql/sql-api.c b/src/lib-sql/sql-api.c
index 39b2913b29..d019b5f934 100644
--- a/src/lib-sql/sql-api.c
+++ b/src/lib-sql/sql-api.c
@@ -3,6 +3,7 @@
 #include "lib.h"
 #include "array.h"
 #include "ioloop.h"
+#include "hash.h"
 #include "str.h"
 #include "time-util.h"
 #include "sql-api-private.h"
@@ -104,6 +105,8 @@ int sql_init_full(const struct sql_settings *set, struct sql_db **db_r,
 
 	i_array_init(&db->module_contexts, 5);
 	db->refcount = 1;
+	hash_table_create(&db->prepared_stmt_hash, default_pool, 0,
+			  str_hash, strcmp);
 	*db_r = db;
 	return 0;
 }
@@ -125,6 +128,8 @@ void sql_unref(struct sql_db **_db)
 		return;
 
 	timeout_remove(&db->to_reconnect);
+	i_assert(hash_table_count(db->prepared_stmt_hash) == 0);
+	hash_table_destroy(&db->prepared_stmt_hash);
 	db->v.deinit(db);
 }
 
@@ -197,6 +202,7 @@ default_sql_prepared_statement_init(struct sql_db *db,
 
 	prep_stmt = i_new(struct sql_prepared_statement, 1);
 	prep_stmt->db = db;
+	prep_stmt->refcount = 1;
 	prep_stmt->query_template = i_strdup(query_template);
 	return prep_stmt;
 }
@@ -271,10 +277,21 @@ static void default_sql_update_stmt(struct sql_transaction_context *ctx,
 struct sql_prepared_statement *
 sql_prepared_statement_init(struct sql_db *db, const char *query_template)
 {
+	struct sql_prepared_statement *stmt;
+
+	stmt = hash_table_lookup(db->prepared_stmt_hash, query_template);
+	if (stmt != NULL) {
+		stmt->refcount++;
+		return stmt;
+	}
+
 	if (db->v.prepared_statement_init != NULL)
-		return db->v.prepared_statement_init(db, query_template);
+		stmt = db->v.prepared_statement_init(db, query_template);
 	else
-		return default_sql_prepared_statement_init(db, query_template);
+		stmt = default_sql_prepared_statement_init(db, query_template);
+
+	hash_table_insert(db->prepared_stmt_hash, stmt->query_template, stmt);
+	return stmt;
 }
 
 void sql_prepared_statement_deinit(struct sql_prepared_statement **_prep_stmt)
@@ -282,6 +299,11 @@ void sql_prepared_statement_deinit(struct sql_prepared_statement **_prep_stmt)
 	struct sql_prepared_statement *prep_stmt = *_prep_stmt;
 
 	*_prep_stmt = NULL;
+
+	i_assert(prep_stmt->refcount > 0);
+	if (--prep_stmt->refcount > 0)
+		return;
+
 	if (prep_stmt->db->v.prepared_statement_deinit != NULL)
 		prep_stmt->db->v.prepared_statement_deinit(prep_stmt);
 	else