diff options
Diffstat (limited to 'sql/opt_range.cc')
| -rw-r--r-- | sql/opt_range.cc | 40 |
1 files changed, 25 insertions, 15 deletions
diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 4944c994d3d..948b268d9a3 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -1264,8 +1264,16 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler) thd= head->in_use; if (!(file= head->file->clone(thd->mem_root))) { + /* + Manually set the error flag. Note: there seems to be quite a few + places where a failure could cause the server to "hang" the client by + sending no response to a query. ATM those are not real errors because + the storage engine calls in question happen to never fail with the + existing storage engines. + */ + thd->net.report_error= 1; /* purecov: inspected */ /* Caller will free the memory */ - goto failure; + goto failure; /* purecov: inspected */ } head->column_bitmaps_set(&column_bitmap, &column_bitmap); @@ -7244,6 +7252,11 @@ check_quick_select(PARAM *param,uint idx,SEL_ARG *tree, bool update_tbl_stats) param->is_ror_scan is cleared if the function detects that the key scan is not a Rowid-Ordered Retrieval scan ( see comments for is_key_scan_ror function for description of which key scans are ROR scans) + + RETURN + #records E(#records) for given subtree + HA_POS_ERROR if subtree cannot be used for record retrieval + */ static ha_rows @@ -7445,27 +7458,24 @@ check_quick_keys(PARAM *param, uint idx, SEL_ARG *key_tree, ROR (Rowid Ordered Retrieval) key scan is a key scan that produces ordered sequence of rowids (ha_xxx::cmp_ref is the comparison function) - An index scan is a ROR scan if it is done using a condition in form + This function is needed to handle a practically-important special case: + an index scan is a ROR scan if it is done using a condition in form - "key1_1=c_1 AND ... AND key1_n=c_n" (1) + "key1_1=c_1 AND ... AND key1_n=c_n" where the index is defined on (key1_1, ..., key1_N [,a_1, ..., a_n]) - and the table has a clustered Primary Key - - PRIMARY KEY(a_1, ..., a_n, b1, ..., b_k) with first key parts being - identical to uncovered parts ot the key being scanned (2) - - Scans on HASH indexes are not ROR scans, - any range scan on clustered primary key is ROR scan (3) + and the table has a clustered Primary Key defined as - Check (1) is made in check_quick_keys() - Check (3) is made check_quick_select() - Check (2) is made by this function. + PRIMARY KEY(a_1, ..., a_n, b1, ..., b_k) + + i.e. the first key parts of it are identical to uncovered parts ot the + key being scanned. This function assumes that the index flags do not + include HA_KEY_SCAN_NOT_ROR flag (that is checked elsewhere). RETURN - TRUE If the scan is ROR-scan - FALSE otherwise + TRUE The scan is ROR-scan + FALSE Otherwise */ static bool is_key_scan_ror(PARAM *param, uint keynr, uint8 nparts) |