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MXS-1196: Handle sequence related fields/functions

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Both 10.3 and Oracle support sequence pseudo colums and corresponding
functions. Getting the next number in the sequence is in both cases
obtained using nextval/nextval() but the current number is in Oracle
obtained using currval/currval() and in 10.3 using lastval/lastval().

These fields/functions are now ignored, in the sense that they will
not show up in the field/function infos. However, they will cause the
type mask of the statement to contain the bit QUERY_TYPE_WRITE so that
statements accessing the sequence will always be sent to the master.
This commit is contained in:
Johan Wikman
2017-05-23 10:04:40 +03:00
parent 61b265467b
commit 9ecd5da255
2 changed files with 130 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc
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@ -90,6 +90,7 @@ typedef struct parsing_info_st
size_t function_infos_capacity;
GWBUF* preparable_stmt;
qc_parse_result_t result;
int32_t type_mask;
#if defined(SS_DEBUG)
skygw_chk_t pi_chk_tail;
#endif
@ -155,6 +156,8 @@ static TABLE_LIST* skygw_get_affected_tables(void* lexptr);
static bool ensure_query_is_parsed(GWBUF* query);
static bool parse_query(GWBUF* querybuf);
static bool query_is_parsed(GWBUF* buf);
int32_t qc_mysql_get_field_info(GWBUF* buf, const QC_FIELD_INFO** infos, uint32_t* n_infos);
#if MYSQL_VERSION_MAJOR >= 10 && MYSQL_VERSION_MINOR >= 3
inline void get_string_and_length(const LEX_CSTRING& ls, const char** s, size_t* length)
@ -224,6 +227,8 @@ int32_t qc_mysql_parse(GWBUF* querybuf, uint32_t collect, int32_t* result)
int32_t qc_mysql_get_type_mask(GWBUF* querybuf, uint32_t* type_mask)
{
int32_t rv = QC_RESULT_OK;
*type_mask = QUERY_TYPE_UNKNOWN;
MYSQL* mysql;
bool succp;
@ -254,12 +259,25 @@ int32_t qc_mysql_get_type_mask(GWBUF* querybuf, uint32_t* type_mask)
if (mysql != NULL)
{
*type_mask = resolve_query_type(pi, (THD *) mysql->thd);
#if MYSQL_VERSION_MAJOR >= 10 && MYSQL_VERSION_MINOR >= 3
// If in 10.3 mode we need to ensure that sequence related functions
// are taken into account. That we can ensure by querying for the fields.
const QC_FIELD_INFO* field_infos;
uint32_t n_field_infos;
rv = qc_mysql_get_field_info(querybuf, &field_infos, &n_field_infos);
if (rv == QC_RESULT_OK)
{
*type_mask |= pi->type_mask;
}
#endif
}
}
}
retblock:
return QC_RESULT_OK;
return rv;
}
/**
@ -2342,6 +2360,43 @@ static void remove_surrounding_back_ticks(char* s)
}
}
static bool should_function_be_ignored(parsing_info_t* pi, const char* func_name)
{
bool rv = false;
// We want to ignore functions that do not really appear as such in an
// actual SQL statement. E.g. "SELECT @a" appears as a function "get_user_var".
if ((strcasecmp(func_name, "decimal_typecast") == 0) ||
(strcasecmp(func_name, "cast_as_char") == 0) ||
(strcasecmp(func_name, "cast_as_date") == 0) ||
(strcasecmp(func_name, "cast_as_datetime") == 0) ||
(strcasecmp(func_name, "cast_as_time") == 0) ||
(strcasecmp(func_name, "cast_as_signed") == 0) ||
(strcasecmp(func_name, "cast_as_unsigned") == 0) ||
(strcasecmp(func_name, "get_user_var") == 0) ||
(strcasecmp(func_name, "get_system_var") == 0) ||
(strcasecmp(func_name, "set_user_var") == 0) ||
(strcasecmp(func_name, "set_system_var") == 0))
{
rv = true;
}
// Any sequence related functions should be ignored as well.
#if MYSQL_VERSION_MAJOR >= 10 && MYSQL_VERSION_MINOR >= 3
if (!rv)
{
if ((strcasecmp(func_name, "lastval") == 0) ||
(strcasecmp(func_name, "nextval") == 0))
{
pi->type_mask |= QUERY_TYPE_WRITE;
rv = true;
}
}
#endif
return rv;
}
static void update_field_infos(parsing_info_t* pi,
collect_source_t source,
Item* item,
@ -2459,17 +2514,7 @@ static void update_field_infos(parsing_info_t* pi,
// We want to ignore functions that do not really appear as such in an
// actual SQL statement. E.g. "SELECT @a" appears as a function "get_user_var".
if ((strcasecmp(func_name, "decimal_typecast") != 0) &&
(strcasecmp(func_name, "cast_as_char") != 0) &&
(strcasecmp(func_name, "cast_as_date") != 0) &&
(strcasecmp(func_name, "cast_as_datetime") != 0) &&
(strcasecmp(func_name, "cast_as_time") != 0) &&
(strcasecmp(func_name, "cast_as_signed") != 0) &&
(strcasecmp(func_name, "cast_as_unsigned") != 0) &&
(strcasecmp(func_name, "get_user_var") != 0) &&
(strcasecmp(func_name, "get_system_var") != 0) &&
(strcasecmp(func_name, "set_user_var") != 0) &&
(strcasecmp(func_name, "set_system_var") != 0))
if (!should_function_be_ignored(pi, func_name))
{
if (strcmp(func_name, "%") == 0)
{