| Bug #72649 | mysql_fetch_fields returns no array of MYSQL_FIELD under linux | ||
|---|---|---|---|
| Submitted: | 14 May 2014 13:21 | Modified: | 4 Aug 2014 5:45 |
| Reporter: | Lyn Matten | Email Updates: | |
| Status: | No Feedback | Impact on me: | |
| Category: | MySQL Server: C API (client library) | Severity: | S2 (Serious) |
| Version: | 5.5.34 | OS: | Linux (Ubuntu & Open Suse) |
| Assigned to: | CPU Architecture: | Any | |
| Tags: | array, MYSQL_FIELD | ||
[4 Jul 2014 5:45]
MySQL Verification Team
Hello Lyn, Thank you for the report. I could not repeat this on OL6 ad with 5.5.38/5.6.20. Could you please provide complete repeatable test script(c script, schema, exact command used for compiling etc)? Thanks, Umesh
[4 Jul 2014 6:10]
MySQL Verification Team
// [root@cluster-repo mysql-5.5.38]# more bug72649.c #include <stdlib.h> #include <stdio.h> #include <mysql.h> int main(int argc, char **argv) { MYSQL *mysql = NULL; mysql = mysql_init(mysql); if (!mysql) { puts("Init faild, out of memory?"); return EXIT_FAILURE; } if (!mysql_real_connect(mysql, "localhost", "root", "", "test", 0, "/tmp/mysql.sock", CLIENT_FOUND_ROWS )) { puts("Connect failed\n"); } else { mysql_query(mysql, "SET NAMES utf8"); if (mysql_query(mysql, "SELECT id,name from test.keyvalue LIMIT 4")) { printf("Query failed: %s\n", mysql_error(mysql)); } else { MYSQL_RES *result = mysql_store_result(mysql); if (!result) { printf("Couldn't get results set: %s\n", mysql_error(mysql)); } else { MYSQL_FIELD *fields; fields = mysql_fetch_fields(result); if (!fields) { printf("Faild fetching fields: %s\n", mysql_error(mysql)); } else { unsigned int i, num_fields = mysql_num_fields(result); for (i = 0; i < num_fields; i++) { printf("FIELD #%d\n", i); printf(" %-20s %s\n", "Field name", fields[i].name); #if MYSQL_VERSION_ID >= 40100 printf(" %-20s %s\n", "Original name", fields[i].org_name); #endif printf(" %-20s %s\n", "From table", fields[i].table); printf(" %-20s %s\n", "Original name", fields[i].org_table); printf(" %-20s %s\n", "Database", fields[i].db); #if MYSQL_VERSION_ID >= 40100 printf(" %-20s %s\n", "Catalog", fields[i].catalog); #endif printf(" %-20s %s\n", "Default", fields[i].def); printf(" %-20s %lu\n", "CREATE field length", fields[i].length); printf(" %-20s %lu\n", "MAX field lengt", fields[i].max_length); #if MYSQL_VERSION_ID >= 40100 printf(" %-20s %u\n", "Field name length", fields[i].name_length); printf(" %-20s %u\n", "Original name length", fields[i].org_name_length); printf(" %-20s %u\n", "Table name length", fields[i].table_length); printf(" %-20s %u\n", "Original name length", fields[i].org_table_length); printf(" %-20s %u\n", "DB name length", fields[i].db_length); printf(" %-20s %u\n", "Catalog name length", fields[i].catalog_length); printf(" %-20s %u\n", "Default length", fields[i].def_length); #endif /* TODO: decimals */ printf("\n"); } } } } } mysql_close(mysql); return EXIT_SUCCESS; } // 5.6 [root@cluster-repo mysql-advanced-5.6.20]# gcc bug72649.c -Wall -g -o bug72649 -L /data/ushastry/server/mysql-advanced-5.6.20/lib/ -I /data/ushastry/server/mysql-advanced-5.6.20/include/ -lmysqlclient_r -lz -lm [root@cluster-repo mysql-advanced-5.6.20]# ./bug72649 FIELD #0 Field name id Original name id From table keyvalue Original name keyvalue Database test Catalog def Default (null) CREATE field length 20 MAX field lengt 1 Field name length 2 Original name length 2 Table name length 8 Original name length 8 DB name length 4 Catalog name length 3 Default length 0 FIELD #1 Field name name Original name name From table keyvalue Original name keyvalue Database test Catalog def Default (null) CREATE field length 750 MAX field lengt 32 Field name length 4 Original name length 4 Table name length 8 Original name length 8 DB name length 4 Catalog name length 3 Default length 0 // 5.5.38 [root@cluster-repo mysql-5.5.38]# gcc bug72649.c -Wall -g -o bug72649 -L /data/ushastry/server/mysql-5.5.38/lib/ -I /data/ushastry/server/mysql-5.5.38/include/ -lmysqlclient_r -lz -lm [root@cluster-repo mysql-5.5.38]# ./bug72649 FIELD #0 Field name id Original name id From table keyvalue Original name keyvalue Database test Catalog def Default (null) CREATE field length 20 MAX field lengt 1 Field name length 2 Original name length 2 Table name length 8 Original name length 8 DB name length 4 Catalog name length 3 Default length 0 FIELD #1 Field name name Original name name From table keyvalue Original name keyvalue Database test Catalog def Default (null) CREATE field length 750 MAX field lengt 32 Field name length 4 Original name length 4 Table name length 8 Original name length 8 DB name length 4 Catalog name length 3 Default length 0
[5 Aug 2014 1:00]
Bugs System
No feedback was provided for this bug for over a month, so it is being suspended automatically. If you are able to provide the information that was originally requested, please do so and change the status of the bug back to "Open".
Description: Calling mysql_fetch_field(MYSQL_RES *result) under Linux with actual mysql server version does not return an array of mysql_fields but only the first resultset. Behavior seems to be the same as mysql_fetch_field. Both have the same declaration: MYSQL_FIELD *mysql_fetch_fields(MYSQL_RES *result) MYSQL_FIELD *mysql_fetch_field(MYSQL_RES *result) Under MAC OS X mysql_fetch_fields work as expected. How to repeat: Perform a SELECT over a table with several column. Use MYSQL_RES *result to get all information about the fields: Perform the example from the manual: unsigned int num_fields; unsigned int i; MYSQL_FIELD *fields; num_fields = mysql_num_fields(result); fields = mysql_fetch_fields(result); for(i = 0; i < num_fields; i++) { printf("Field %u is %s\n", i, fields[i].name); } http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-fields.html Program will stop with segementation fault for fields[i].name when i == 1. Suggested fix: Not sure why this works under MAC OS X. From my perspective the declaration should be an array over MYSQL_FIELD: MYSQL_FIELD **mysql_fetch_fields(MYSQL_RES *result)