| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.impl.store.access.sort.MergeSortInfo |
| 4 | |
| 5 | Copyright 1999, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.impl.store.access.sort; |
| 22 | |
| 23 | import org.apache.derby.iapi.store.access.SortInfo; |
| 24 | |
| 25 | import org.apache.derby.iapi.error.StandardException; |
| 26 | |
| 27 | import org.apache.derby.iapi.reference.SQLState; |
| 28 | |
| 29 | import org.apache.derby.iapi.services.i18n.MessageService; |
| 30 | |
| 31 | import java.util.Vector; |
| 32 | import java.util.Properties; |
| 33 | |
| 34 | /** |
| 35 | |
| 36 | This object provides performance information related to a sort. |
| 37 | The information is accumulated during operations on a SortController() and |
| 38 | then copied into this object and returned by a call to |
| 39 | SortController.getSortInfo(). |
| 40 | |
| 41 | @see org.apache.derby.iapi.store.access.SortController#getSortInfo() |
| 42 | |
| 43 | **/ |
| 44 | class MergeSortInfo implements SortInfo |
| 45 | { |
| 46 | /** |
| 47 | * Performance counters ... |
| 48 | */ |
| 49 | |
| 50 | private String stat_sortType; |
| 51 | // private long stat_estimMemUsed; |
| 52 | private int stat_numRowsInput; |
| 53 | private int stat_numRowsOutput; |
| 54 | private int stat_numMergeRuns; |
| 55 | private Vector stat_mergeRunsSize; |
| 56 | |
| 57 | |
| 58 | /* Constructors for This class: */ |
| 59 | MergeSortInfo(MergeInserter sort) |
| 60 | { |
| 61 | // copy perfomance state out of sort, to get a fixed set of stats |
| 62 | stat_sortType = sort.stat_sortType; |
| 63 | // stat_estimMemUsed = sort.estimatedMemoryUsed; |
| 64 | stat_numRowsInput = sort.stat_numRowsInput; |
| 65 | stat_numRowsOutput = sort.stat_numRowsOutput; |
| 66 | stat_numMergeRuns = sort.stat_numMergeRuns; |
| 67 | stat_mergeRunsSize = sort.stat_mergeRunsSize; |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * Return all information gathered about the sort. |
| 72 | * <p> |
| 73 | * This routine returns a list of properties which contains all information |
| 74 | * gathered about the sort. If a Property is passed in, then that property |
| 75 | * list is appended to, otherwise a new property object is created and |
| 76 | * returned. |
| 77 | * <p> |
| 78 | * Not all sorts may support all properties, if the property is not |
| 79 | * supported then it will not be returned. The following is a list of |
| 80 | * properties that may be returned: |
| 81 | * |
| 82 | * sortType |
| 83 | * - type of the sort being performed: |
| 84 | * internal |
| 85 | * external |
| 86 | * numRowsInput |
| 87 | * - the number of rows input to the sort. This |
| 88 | * number includes duplicates. |
| 89 | * numRowsOutput |
| 90 | * - the number of rows to be output by the sort. This number |
| 91 | * may be different from numRowsInput since duplicates may not |
| 92 | * be output. |
| 93 | * numMergeRuns |
| 94 | * - the number of merge runs for the sort. |
| 95 | * Applicable to external sorts only. |
| 96 | * Note: when a SortController is closed, numMergeRuns may increase by 1, to |
| 97 | * reflect the additional merge run that may be created for |
| 98 | * any data still in the sort buffer. |
| 99 | * mergeRunsSize |
| 100 | * - the size (number of rows) of each merge run for the sort. |
| 101 | * Applicable to external sorts only. |
| 102 | * e.g. [3,3,2] indicates 3 merge runs, where the first two runs |
| 103 | * have 3 rows each, and the last run has 2 rows. |
| 104 | * Note: when a SortController is closed, this vector may get an |
| 105 | * additional element, to reflect the additional merge run that |
| 106 | * may be created for any data still in the sort buffer. |
| 107 | * NOTE - this list will be expanded as more information about the sort |
| 108 | * is gathered and returned. |
| 109 | * |
| 110 | * @param prop Property list to fill in. |
| 111 | * |
| 112 | * @exception StandardException Standard exception policy. |
| 113 | **/ |
| 114 | |
| 115 | public Properties getAllSortInfo(Properties prop) |
| 116 | throws StandardException |
| 117 | { |
| 118 | if (prop == null) |
| 119 | prop = new Properties(); |
| 120 | |
| 121 | prop.put( |
| 122 | MessageService.getTextMessage(SQLState.STORE_RTS_SORT_TYPE), |
| 123 | "external".equals(this.stat_sortType) ? |
| 124 | MessageService.getTextMessage(SQLState.STORE_RTS_EXTERNAL) : |
| 125 | MessageService.getTextMessage(SQLState.STORE_RTS_INTERNAL)); |
| 126 | // prop.put( |
| 127 | // MessageService.getTextMessage(SQLState.STORE_RTS_ESTIMATED_MEMORY_USED), |
| 128 | // Long.toString(stat_estimMemUsed)); |
| 129 | prop.put( |
| 130 | MessageService.getTextMessage(SQLState.STORE_RTS_NUM_ROWS_INPUT), |
| 131 | Integer.toString(stat_numRowsInput)); |
| 132 | prop.put( |
| 133 | MessageService.getTextMessage(SQLState.STORE_RTS_NUM_ROWS_OUTPUT), |
| 134 | Integer.toString(stat_numRowsOutput)); |
| 135 | if (this.stat_sortType == "external") |
| 136 | { |
| 137 | prop.put( |
| 138 | MessageService.getTextMessage(SQLState.STORE_RTS_NUM_MERGE_RUNS), |
| 139 | Integer.toString(stat_numMergeRuns)); |
| 140 | prop.put( |
| 141 | MessageService.getTextMessage(SQLState.STORE_RTS_MERGE_RUNS_SIZE), |
| 142 | stat_mergeRunsSize.toString()); |
| 143 | } |
| 144 | return(prop); |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | |
| 149 | /** |
| 150 | * estimMemUsed IS NOT CURRENTLY SUPPORTED SINCE IT IS UNRELIABLE |
| 151 | * estimMemUsed |
| 152 | * - the estimated memory used by the sort. |
| 153 | * |
| 154 | * This is only measured when the system runs out of sort |
| 155 | * buffer space, AND when it tries to avoid doing an external sort. |
| 156 | * It measures this by subtracting the memory usage at initialization |
| 157 | * from the memory usage at the time we are trying to avoid doing an |
| 158 | * external sort. The result could be negative: this probably indicates |
| 159 | * that there has been some garbage collection in the interim. |
| 160 | * If the attempt at keeping the sort internal succeeds, the buffer grows |
| 161 | * but the increased memory usage is not measured. |
| 162 | * |
| 163 | * The system may never measure the memory usage. This happens if |
| 164 | * it never runs out of sort buffer space, or if it is set up not |
| 165 | * to avoid external sorts. In cases that it is not measured, it returns 0. |
| 166 | * |
| 167 | * In future, this info may improve with an improved JVM API. |
| 168 | */ |
| 169 | |