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Fix query classifier initialization data race

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The initialization code does some modification to the global code
(something about a page cache) and causes warnings with TSAN.
This commit is contained in:
Markus Mäkelä 2018-08-10 15:14:16 +03:00
parent 70fa300fe1
commit c1f930d23d
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GPG Key ID: 72D48FCE664F7B19
1 changed files with 8 additions and 0 deletions
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8
query_classifier/qc_sqlite/qc_sqlite.cc
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@ -26,6 +26,7 @@
#include <new>
#include <string>
#include <vector>
#include <mutex>
#include <maxscale/alloc.h>
#include <maxscale/log_manager.h>
@ -143,6 +144,7 @@ static struct
qc_sql_mode_t sql_mode;
qc_parse_as_t parse_as;
QC_NAME_MAPPING* pFunction_name_mappings;
std::mutex lock;
} this_unit;
/**
@ -4487,6 +4489,11 @@ static int32_t qc_sqlite_thread_init(void)
ss_dassert(this_unit.initialized);
ss_dassert(!this_thread.initialized);
// Thread initialization must be done behind a global lock. SQLite can perform
// global initialization which has a data race in the page cache code.
// TODO: Figure out why this happens
std::lock_guard<std::mutex> guard(this_unit.lock);
// TODO: It may be sufficient to have a single in-memory database for all threads.
int rc = sqlite3_open(":memory:", &this_thread.pDb);
if (rc == SQLITE_OK)
@ -4546,6 +4553,7 @@ static void qc_sqlite_thread_end(void)
ss_dassert(this_thread.initialized);
ss_dassert(this_thread.pDb);
std::lock_guard<std::mutex> guard(this_unit.lock);
int rc = sqlite3_close(this_thread.pDb);
if (rc != SQLITE_OK)