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| 1 # Run this TCL script using "testfixture" in order get a report that shows |
| 2 # how much disk space is used by a particular data to actually store data |
| 3 # versus how much space is unused. |
| 4 # |
| 5 |
| 6 if {[catch { |
| 7 |
| 8 # Get the name of the database to analyze |
| 9 # |
| 10 #set argv $argv0 |
| 11 if {[llength $argv]!=1} { |
| 12 puts stderr "Usage: $argv0 database-name" |
| 13 exit 1 |
| 14 } |
| 15 set file_to_analyze [lindex $argv 0] |
| 16 if {![file exists $file_to_analyze]} { |
| 17 puts stderr "No such file: $file_to_analyze" |
| 18 exit 1 |
| 19 } |
| 20 if {![file readable $file_to_analyze]} { |
| 21 puts stderr "File is not readable: $file_to_analyze" |
| 22 exit 1 |
| 23 } |
| 24 if {[file size $file_to_analyze]<512} { |
| 25 puts stderr "Empty or malformed database: $file_to_analyze" |
| 26 exit 1 |
| 27 } |
| 28 |
| 29 # Open the database |
| 30 # |
| 31 sqlite3 db [lindex $argv 0] |
| 32 register_dbstat_vtab db |
| 33 |
| 34 set pageSize [db one {PRAGMA page_size}] |
| 35 |
| 36 #set DB [btree_open [lindex $argv 0] 1000 0] |
| 37 |
| 38 # In-memory database for collecting statistics. This script loops through |
| 39 # the tables and indices in the database being analyzed, adding a row for each |
| 40 # to an in-memory database (for which the schema is shown below). It then |
| 41 # queries the in-memory db to produce the space-analysis report. |
| 42 # |
| 43 sqlite3 mem :memory: |
| 44 set tabledef\ |
| 45 {CREATE TABLE space_used( |
| 46 name clob, -- Name of a table or index in the database file |
| 47 tblname clob, -- Name of associated table |
| 48 is_index boolean, -- TRUE if it is an index, false for a table |
| 49 nentry int, -- Number of entries in the BTree |
| 50 leaf_entries int, -- Number of leaf entries |
| 51 payload int, -- Total amount of data stored in this table or index |
| 52 ovfl_payload int, -- Total amount of data stored on overflow pages |
| 53 ovfl_cnt int, -- Number of entries that use overflow |
| 54 mx_payload int, -- Maximum payload size |
| 55 int_pages int, -- Number of interior pages used |
| 56 leaf_pages int, -- Number of leaf pages used |
| 57 ovfl_pages int, -- Number of overflow pages used |
| 58 int_unused int, -- Number of unused bytes on interior pages |
| 59 leaf_unused int, -- Number of unused bytes on primary pages |
| 60 ovfl_unused int, -- Number of unused bytes on overflow pages |
| 61 gap_cnt int -- Number of gaps in the page layout |
| 62 );} |
| 63 mem eval $tabledef |
| 64 |
| 65 # Create a temporary "dbstat" virtual table. |
| 66 # |
| 67 db eval { |
| 68 CREATE VIRTUAL TABLE temp.stat USING dbstat; |
| 69 CREATE TEMP TABLE dbstat AS SELECT * FROM temp.stat ORDER BY name, path; |
| 70 DROP TABLE temp.stat; |
| 71 } |
| 72 |
| 73 proc isleaf {pagetype is_index} { |
| 74 return [expr {$pagetype == "leaf" || ($pagetype == "internal" && $is_index)}] |
| 75 } |
| 76 proc isoverflow {pagetype is_index} { |
| 77 return [expr {$pagetype == "overflow"}] |
| 78 } |
| 79 proc isinternal {pagetype is_index} { |
| 80 return [expr {$pagetype == "internal" && $is_index==0}] |
| 81 } |
| 82 |
| 83 db func isleaf isleaf |
| 84 db func isinternal isinternal |
| 85 db func isoverflow isoverflow |
| 86 |
| 87 set sql { SELECT name, tbl_name FROM sqlite_master WHERE rootpage>0 } |
| 88 foreach {name tblname} [concat sqlite_master sqlite_master [db eval $sql]] { |
| 89 |
| 90 set is_index [expr {$name!=$tblname}] |
| 91 db eval { |
| 92 SELECT |
| 93 sum(ncell) AS nentry, |
| 94 sum(isleaf(pagetype, $is_index) * ncell) AS leaf_entries, |
| 95 sum(payload) AS payload, |
| 96 sum(isoverflow(pagetype, $is_index) * payload) AS ovfl_payload, |
| 97 sum(path LIKE '%+000000') AS ovfl_cnt, |
| 98 max(mx_payload) AS mx_payload, |
| 99 sum(isinternal(pagetype, $is_index)) AS int_pages, |
| 100 sum(isleaf(pagetype, $is_index)) AS leaf_pages, |
| 101 sum(isoverflow(pagetype, $is_index)) AS ovfl_pages, |
| 102 sum(isinternal(pagetype, $is_index) * unused) AS int_unused, |
| 103 sum(isleaf(pagetype, $is_index) * unused) AS leaf_unused, |
| 104 sum(isoverflow(pagetype, $is_index) * unused) AS ovfl_unused |
| 105 FROM temp.dbstat WHERE name = $name |
| 106 } break |
| 107 |
| 108 # Column 'gap_cnt' is set to the number of non-contiguous entries in the |
| 109 # list of pages visited if the b-tree structure is traversed in a top-down |
| 110 # fashion (each node visited before its child-tree is passed). Any overflow |
| 111 # chains present are traversed from start to finish before any child-tree |
| 112 # is. |
| 113 # |
| 114 set gap_cnt 0 |
| 115 set pglist [db eval { |
| 116 SELECT pageno FROM temp.dbstat WHERE name = $name ORDER BY rowid |
| 117 }] |
| 118 set prev [lindex $pglist 0] |
| 119 foreach pgno [lrange $pglist 1 end] { |
| 120 if {$pgno != $prev+1} {incr gap_cnt} |
| 121 set prev $pgno |
| 122 } |
| 123 |
| 124 mem eval { |
| 125 INSERT INTO space_used VALUES( |
| 126 $name, |
| 127 $tblname, |
| 128 $is_index, |
| 129 $nentry, |
| 130 $leaf_entries, |
| 131 $payload, |
| 132 $ovfl_payload, |
| 133 $ovfl_cnt, |
| 134 $mx_payload, |
| 135 $int_pages, |
| 136 $leaf_pages, |
| 137 $ovfl_pages, |
| 138 $int_unused, |
| 139 $leaf_unused, |
| 140 $ovfl_unused, |
| 141 $gap_cnt |
| 142 ); |
| 143 } |
| 144 } |
| 145 |
| 146 proc integerify {real} { |
| 147 if {[string is double -strict $real]} { |
| 148 return [expr {int($real)}] |
| 149 } else { |
| 150 return 0 |
| 151 } |
| 152 } |
| 153 mem function int integerify |
| 154 |
| 155 # Quote a string for use in an SQL query. Examples: |
| 156 # |
| 157 # [quote {hello world}] == {'hello world'} |
| 158 # [quote {hello world's}] == {'hello world''s'} |
| 159 # |
| 160 proc quote {txt} { |
| 161 regsub -all ' $txt '' q |
| 162 return '$q' |
| 163 } |
| 164 |
| 165 # Generate a single line of output in the statistics section of the |
| 166 # report. |
| 167 # |
| 168 proc statline {title value {extra {}}} { |
| 169 set len [string length $title] |
| 170 set dots [string range {......................................} $len end] |
| 171 set len [string length $value] |
| 172 set sp2 [string range { } $len end] |
| 173 if {$extra ne ""} { |
| 174 set extra " $extra" |
| 175 } |
| 176 puts "$title$dots $value$sp2$extra" |
| 177 } |
| 178 |
| 179 # Generate a formatted percentage value for $num/$denom |
| 180 # |
| 181 proc percent {num denom {of {}}} { |
| 182 if {$denom==0.0} {return ""} |
| 183 set v [expr {$num*100.0/$denom}] |
| 184 set of {} |
| 185 if {$v==100.0 || $v<0.001 || ($v>1.0 && $v<99.0)} { |
| 186 return [format {%5.1f%% %s} $v $of] |
| 187 } elseif {$v<0.1 || $v>99.9} { |
| 188 return [format {%7.3f%% %s} $v $of] |
| 189 } else { |
| 190 return [format {%6.2f%% %s} $v $of] |
| 191 } |
| 192 } |
| 193 |
| 194 proc divide {num denom} { |
| 195 if {$denom==0} {return 0.0} |
| 196 return [format %.2f [expr double($num)/double($denom)]] |
| 197 } |
| 198 |
| 199 # Generate a subreport that covers some subset of the database. |
| 200 # the $where clause determines which subset to analyze. |
| 201 # |
| 202 proc subreport {title where} { |
| 203 global pageSize file_pgcnt |
| 204 |
| 205 # Query the in-memory database for the sum of various statistics |
| 206 # for the subset of tables/indices identified by the WHERE clause in |
| 207 # $where. Note that even if the WHERE clause matches no rows, the |
| 208 # following query returns exactly one row (because it is an aggregate). |
| 209 # |
| 210 # The results of the query are stored directly by SQLite into local |
| 211 # variables (i.e. $nentry, $nleaf etc.). |
| 212 # |
| 213 mem eval " |
| 214 SELECT |
| 215 int(sum(nentry)) AS nentry, |
| 216 int(sum(leaf_entries)) AS nleaf, |
| 217 int(sum(payload)) AS payload, |
| 218 int(sum(ovfl_payload)) AS ovfl_payload, |
| 219 max(mx_payload) AS mx_payload, |
| 220 int(sum(ovfl_cnt)) as ovfl_cnt, |
| 221 int(sum(leaf_pages)) AS leaf_pages, |
| 222 int(sum(int_pages)) AS int_pages, |
| 223 int(sum(ovfl_pages)) AS ovfl_pages, |
| 224 int(sum(leaf_unused)) AS leaf_unused, |
| 225 int(sum(int_unused)) AS int_unused, |
| 226 int(sum(ovfl_unused)) AS ovfl_unused, |
| 227 int(sum(gap_cnt)) AS gap_cnt |
| 228 FROM space_used WHERE $where" {} {} |
| 229 |
| 230 # Output the sub-report title, nicely decorated with * characters. |
| 231 # |
| 232 puts "" |
| 233 set len [string length $title] |
| 234 set stars [string repeat * [expr 65-$len]] |
| 235 puts "*** $title $stars" |
| 236 puts "" |
| 237 |
| 238 # Calculate statistics and store the results in TCL variables, as follows: |
| 239 # |
| 240 # total_pages: Database pages consumed. |
| 241 # total_pages_percent: Pages consumed as a percentage of the file. |
| 242 # storage: Bytes consumed. |
| 243 # payload_percent: Payload bytes used as a percentage of $storage. |
| 244 # total_unused: Unused bytes on pages. |
| 245 # avg_payload: Average payload per btree entry. |
| 246 # avg_fanout: Average fanout for internal pages. |
| 247 # avg_unused: Average unused bytes per btree entry. |
| 248 # ovfl_cnt_percent: Percentage of btree entries that use overflow pages. |
| 249 # |
| 250 set total_pages [expr {$leaf_pages+$int_pages+$ovfl_pages}] |
| 251 set total_pages_percent [percent $total_pages $file_pgcnt] |
| 252 set storage [expr {$total_pages*$pageSize}] |
| 253 set payload_percent [percent $payload $storage {of storage consumed}] |
| 254 set total_unused [expr {$ovfl_unused+$int_unused+$leaf_unused}] |
| 255 set avg_payload [divide $payload $nleaf] |
| 256 set avg_unused [divide $total_unused $nleaf] |
| 257 if {$int_pages>0} { |
| 258 # TODO: Is this formula correct? |
| 259 set nTab [mem eval " |
| 260 SELECT count(*) FROM ( |
| 261 SELECT DISTINCT tblname FROM space_used WHERE $where AND is_index=0 |
| 262 ) |
| 263 "] |
| 264 set avg_fanout [mem eval " |
| 265 SELECT (sum(leaf_pages+int_pages)-$nTab)/sum(int_pages) FROM space_used |
| 266 WHERE $where AND is_index = 0 |
| 267 "] |
| 268 set avg_fanout [format %.2f $avg_fanout] |
| 269 } |
| 270 set ovfl_cnt_percent [percent $ovfl_cnt $nleaf {of all entries}] |
| 271 |
| 272 # Print out the sub-report statistics. |
| 273 # |
| 274 statline {Percentage of total database} $total_pages_percent |
| 275 statline {Number of entries} $nleaf |
| 276 statline {Bytes of storage consumed} $storage |
| 277 statline {Bytes of payload} $payload $payload_percent |
| 278 statline {Average payload per entry} $avg_payload |
| 279 statline {Average unused bytes per entry} $avg_unused |
| 280 if {[info exists avg_fanout]} { |
| 281 statline {Average fanout} $avg_fanout |
| 282 } |
| 283 if {$total_pages>1} { |
| 284 set fragmentation [percent $gap_cnt [expr {$total_pages-1}] {fragmentation}] |
| 285 statline {Fragmentation} $fragmentation |
| 286 } |
| 287 statline {Maximum payload per entry} $mx_payload |
| 288 statline {Entries that use overflow} $ovfl_cnt $ovfl_cnt_percent |
| 289 if {$int_pages>0} { |
| 290 statline {Index pages used} $int_pages |
| 291 } |
| 292 statline {Primary pages used} $leaf_pages |
| 293 statline {Overflow pages used} $ovfl_pages |
| 294 statline {Total pages used} $total_pages |
| 295 if {$int_unused>0} { |
| 296 set int_unused_percent \ |
| 297 [percent $int_unused [expr {$int_pages*$pageSize}] {of index space}] |
| 298 statline "Unused bytes on index pages" $int_unused $int_unused_percent |
| 299 } |
| 300 statline "Unused bytes on primary pages" $leaf_unused \ |
| 301 [percent $leaf_unused [expr {$leaf_pages*$pageSize}] {of primary space}] |
| 302 statline "Unused bytes on overflow pages" $ovfl_unused \ |
| 303 [percent $ovfl_unused [expr {$ovfl_pages*$pageSize}] {of overflow space}] |
| 304 statline "Unused bytes on all pages" $total_unused \ |
| 305 [percent $total_unused $storage {of all space}] |
| 306 return 1 |
| 307 } |
| 308 |
| 309 # Calculate the overhead in pages caused by auto-vacuum. |
| 310 # |
| 311 # This procedure calculates and returns the number of pages used by the |
| 312 # auto-vacuum 'pointer-map'. If the database does not support auto-vacuum, |
| 313 # then 0 is returned. The two arguments are the size of the database file in |
| 314 # pages and the page size used by the database (in bytes). |
| 315 proc autovacuum_overhead {filePages pageSize} { |
| 316 |
| 317 # Set $autovacuum to non-zero for databases that support auto-vacuum. |
| 318 set autovacuum [db one {PRAGMA auto_vacuum}] |
| 319 |
| 320 # If the database is not an auto-vacuum database or the file consists |
| 321 # of one page only then there is no overhead for auto-vacuum. Return zero. |
| 322 if {0==$autovacuum || $filePages==1} { |
| 323 return 0 |
| 324 } |
| 325 |
| 326 # The number of entries on each pointer map page. The layout of the |
| 327 # database file is one pointer-map page, followed by $ptrsPerPage other |
| 328 # pages, followed by a pointer-map page etc. The first pointer-map page |
| 329 # is the second page of the file overall. |
| 330 set ptrsPerPage [expr double($pageSize/5)] |
| 331 |
| 332 # Return the number of pointer map pages in the database. |
| 333 return [expr int(ceil( ($filePages-1.0)/($ptrsPerPage+1.0) ))] |
| 334 } |
| 335 |
| 336 |
| 337 # Calculate the summary statistics for the database and store the results |
| 338 # in TCL variables. They are output below. Variables are as follows: |
| 339 # |
| 340 # pageSize: Size of each page in bytes. |
| 341 # file_bytes: File size in bytes. |
| 342 # file_pgcnt: Number of pages in the file. |
| 343 # file_pgcnt2: Number of pages in the file (calculated). |
| 344 # av_pgcnt: Pages consumed by the auto-vacuum pointer-map. |
| 345 # av_percent: Percentage of the file consumed by auto-vacuum pointer-map. |
| 346 # inuse_pgcnt: Data pages in the file. |
| 347 # inuse_percent: Percentage of pages used to store data. |
| 348 # free_pgcnt: Free pages calculated as (<total pages> - <in-use pages>) |
| 349 # free_pgcnt2: Free pages in the file according to the file header. |
| 350 # free_percent: Percentage of file consumed by free pages (calculated). |
| 351 # free_percent2: Percentage of file consumed by free pages (header). |
| 352 # ntable: Number of tables in the db. |
| 353 # nindex: Number of indices in the db. |
| 354 # nautoindex: Number of indices created automatically. |
| 355 # nmanindex: Number of indices created manually. |
| 356 # user_payload: Number of bytes of payload in table btrees |
| 357 # (not including sqlite_master) |
| 358 # user_percent: $user_payload as a percentage of total file size. |
| 359 |
| 360 set file_bytes [file size $file_to_analyze] |
| 361 set file_pgcnt [expr {$file_bytes/$pageSize}] |
| 362 |
| 363 set av_pgcnt [autovacuum_overhead $file_pgcnt $pageSize] |
| 364 set av_percent [percent $av_pgcnt $file_pgcnt] |
| 365 |
| 366 set sql {SELECT sum(leaf_pages+int_pages+ovfl_pages) FROM space_used} |
| 367 set inuse_pgcnt [expr int([mem eval $sql])] |
| 368 set inuse_percent [percent $inuse_pgcnt $file_pgcnt] |
| 369 |
| 370 set free_pgcnt [expr $file_pgcnt-$inuse_pgcnt-$av_pgcnt] |
| 371 set free_percent [percent $free_pgcnt $file_pgcnt] |
| 372 set free_pgcnt2 [db one {PRAGMA freelist_count}] |
| 373 set free_percent2 [percent $free_pgcnt2 $file_pgcnt] |
| 374 |
| 375 set file_pgcnt2 [expr {$inuse_pgcnt+$free_pgcnt2+$av_pgcnt}] |
| 376 |
| 377 set ntable [db eval {SELECT count(*)+1 FROM sqlite_master WHERE type='table'}] |
| 378 set nindex [db eval {SELECT count(*) FROM sqlite_master WHERE type='index'}] |
| 379 set sql {SELECT count(*) FROM sqlite_master WHERE name LIKE 'sqlite_autoindex%'} |
| 380 set nautoindex [db eval $sql] |
| 381 set nmanindex [expr {$nindex-$nautoindex}] |
| 382 |
| 383 # set total_payload [mem eval "SELECT sum(payload) FROM space_used"] |
| 384 set user_payload [mem one {SELECT int(sum(payload)) FROM space_used |
| 385 WHERE NOT is_index AND name NOT LIKE 'sqlite_master'}] |
| 386 set user_percent [percent $user_payload $file_bytes] |
| 387 |
| 388 # Output the summary statistics calculated above. |
| 389 # |
| 390 puts "/** Disk-Space Utilization Report For $file_to_analyze" |
| 391 catch { |
| 392 puts "*** As of [clock format [clock seconds] -format {%Y-%b-%d %H:%M:%S}]" |
| 393 } |
| 394 puts "" |
| 395 statline {Page size in bytes} $pageSize |
| 396 statline {Pages in the whole file (measured)} $file_pgcnt |
| 397 statline {Pages in the whole file (calculated)} $file_pgcnt2 |
| 398 statline {Pages that store data} $inuse_pgcnt $inuse_percent |
| 399 statline {Pages on the freelist (per header)} $free_pgcnt2 $free_percent2 |
| 400 statline {Pages on the freelist (calculated)} $free_pgcnt $free_percent |
| 401 statline {Pages of auto-vacuum overhead} $av_pgcnt $av_percent |
| 402 statline {Number of tables in the database} $ntable |
| 403 statline {Number of indices} $nindex |
| 404 statline {Number of named indices} $nmanindex |
| 405 statline {Automatically generated indices} $nautoindex |
| 406 statline {Size of the file in bytes} $file_bytes |
| 407 statline {Bytes of user payload stored} $user_payload $user_percent |
| 408 |
| 409 # Output table rankings |
| 410 # |
| 411 puts "" |
| 412 puts "*** Page counts for all tables with their indices ********************" |
| 413 puts "" |
| 414 mem eval {SELECT tblname, count(*) AS cnt, |
| 415 int(sum(int_pages+leaf_pages+ovfl_pages)) AS size |
| 416 FROM space_used GROUP BY tblname ORDER BY size+0 DESC, tblname} {} { |
| 417 statline [string toupper $tblname] $size [percent $size $file_pgcnt] |
| 418 } |
| 419 |
| 420 # Output subreports |
| 421 # |
| 422 if {$nindex>0} { |
| 423 subreport {All tables and indices} 1 |
| 424 } |
| 425 subreport {All tables} {NOT is_index} |
| 426 if {$nindex>0} { |
| 427 subreport {All indices} {is_index} |
| 428 } |
| 429 foreach tbl [mem eval {SELECT name FROM space_used WHERE NOT is_index |
| 430 ORDER BY name}] { |
| 431 regsub ' $tbl '' qn |
| 432 set name [string toupper $tbl] |
| 433 set n [mem eval "SELECT count(*) FROM space_used WHERE tblname='$qn'"] |
| 434 if {$n>1} { |
| 435 subreport "Table $name and all its indices" "tblname='$qn'" |
| 436 subreport "Table $name w/o any indices" "name='$qn'" |
| 437 subreport "Indices of table $name" "tblname='$qn' AND is_index" |
| 438 } else { |
| 439 subreport "Table $name" "name='$qn'" |
| 440 } |
| 441 } |
| 442 |
| 443 # Output instructions on what the numbers above mean. |
| 444 # |
| 445 puts { |
| 446 *** Definitions ****************************************************** |
| 447 |
| 448 Page size in bytes |
| 449 |
| 450 The number of bytes in a single page of the database file. |
| 451 Usually 1024. |
| 452 |
| 453 Number of pages in the whole file |
| 454 } |
| 455 puts \ |
| 456 " The number of $pageSize-byte pages that go into forming the complete |
| 457 database" |
| 458 puts \ |
| 459 { |
| 460 Pages that store data |
| 461 |
| 462 The number of pages that store data, either as primary B*Tree pages or |
| 463 as overflow pages. The number at the right is the data pages divided by |
| 464 the total number of pages in the file. |
| 465 |
| 466 Pages on the freelist |
| 467 |
| 468 The number of pages that are not currently in use but are reserved for |
| 469 future use. The percentage at the right is the number of freelist pages |
| 470 divided by the total number of pages in the file. |
| 471 |
| 472 Pages of auto-vacuum overhead |
| 473 |
| 474 The number of pages that store data used by the database to facilitate |
| 475 auto-vacuum. This is zero for databases that do not support auto-vacuum. |
| 476 |
| 477 Number of tables in the database |
| 478 |
| 479 The number of tables in the database, including the SQLITE_MASTER table |
| 480 used to store schema information. |
| 481 |
| 482 Number of indices |
| 483 |
| 484 The total number of indices in the database. |
| 485 |
| 486 Number of named indices |
| 487 |
| 488 The number of indices created using an explicit CREATE INDEX statement. |
| 489 |
| 490 Automatically generated indices |
| 491 |
| 492 The number of indices used to implement PRIMARY KEY or UNIQUE constraints |
| 493 on tables. |
| 494 |
| 495 Size of the file in bytes |
| 496 |
| 497 The total amount of disk space used by the entire database files. |
| 498 |
| 499 Bytes of user payload stored |
| 500 |
| 501 The total number of bytes of user payload stored in the database. The |
| 502 schema information in the SQLITE_MASTER table is not counted when |
| 503 computing this number. The percentage at the right shows the payload |
| 504 divided by the total file size. |
| 505 |
| 506 Percentage of total database |
| 507 |
| 508 The amount of the complete database file that is devoted to storing |
| 509 information described by this category. |
| 510 |
| 511 Number of entries |
| 512 |
| 513 The total number of B-Tree key/value pairs stored under this category. |
| 514 |
| 515 Bytes of storage consumed |
| 516 |
| 517 The total amount of disk space required to store all B-Tree entries |
| 518 under this category. The is the total number of pages used times |
| 519 the pages size. |
| 520 |
| 521 Bytes of payload |
| 522 |
| 523 The amount of payload stored under this category. Payload is the data |
| 524 part of table entries and the key part of index entries. The percentage |
| 525 at the right is the bytes of payload divided by the bytes of storage |
| 526 consumed. |
| 527 |
| 528 Average payload per entry |
| 529 |
| 530 The average amount of payload on each entry. This is just the bytes of |
| 531 payload divided by the number of entries. |
| 532 |
| 533 Average unused bytes per entry |
| 534 |
| 535 The average amount of free space remaining on all pages under this |
| 536 category on a per-entry basis. This is the number of unused bytes on |
| 537 all pages divided by the number of entries. |
| 538 |
| 539 Fragmentation |
| 540 |
| 541 The percentage of pages in the table or index that are not |
| 542 consecutive in the disk file. Many filesystems are optimized |
| 543 for sequential file access so smaller fragmentation numbers |
| 544 sometimes result in faster queries, especially for larger |
| 545 database files that do not fit in the disk cache. |
| 546 |
| 547 Maximum payload per entry |
| 548 |
| 549 The largest payload size of any entry. |
| 550 |
| 551 Entries that use overflow |
| 552 |
| 553 The number of entries that user one or more overflow pages. |
| 554 |
| 555 Total pages used |
| 556 |
| 557 This is the number of pages used to hold all information in the current |
| 558 category. This is the sum of index, primary, and overflow pages. |
| 559 |
| 560 Index pages used |
| 561 |
| 562 This is the number of pages in a table B-tree that hold only key (rowid) |
| 563 information and no data. |
| 564 |
| 565 Primary pages used |
| 566 |
| 567 This is the number of B-tree pages that hold both key and data. |
| 568 |
| 569 Overflow pages used |
| 570 |
| 571 The total number of overflow pages used for this category. |
| 572 |
| 573 Unused bytes on index pages |
| 574 |
| 575 The total number of bytes of unused space on all index pages. The |
| 576 percentage at the right is the number of unused bytes divided by the |
| 577 total number of bytes on index pages. |
| 578 |
| 579 Unused bytes on primary pages |
| 580 |
| 581 The total number of bytes of unused space on all primary pages. The |
| 582 percentage at the right is the number of unused bytes divided by the |
| 583 total number of bytes on primary pages. |
| 584 |
| 585 Unused bytes on overflow pages |
| 586 |
| 587 The total number of bytes of unused space on all overflow pages. The |
| 588 percentage at the right is the number of unused bytes divided by the |
| 589 total number of bytes on overflow pages. |
| 590 |
| 591 Unused bytes on all pages |
| 592 |
| 593 The total number of bytes of unused space on all primary and overflow |
| 594 pages. The percentage at the right is the number of unused bytes |
| 595 divided by the total number of bytes. |
| 596 } |
| 597 |
| 598 # Output a dump of the in-memory database. This can be used for more |
| 599 # complex offline analysis. |
| 600 # |
| 601 puts "**********************************************************************" |
| 602 puts "The entire text of this report can be sourced into any SQL database" |
| 603 puts "engine for further analysis. All of the text above is an SQL comment." |
| 604 puts "The data used to generate this report follows:" |
| 605 puts "*/" |
| 606 puts "BEGIN;" |
| 607 puts $tabledef |
| 608 unset -nocomplain x |
| 609 mem eval {SELECT * FROM space_used} x { |
| 610 puts -nonewline "INSERT INTO space_used VALUES" |
| 611 set sep ( |
| 612 foreach col $x(*) { |
| 613 set v $x($col) |
| 614 if {$v=="" || ![string is double $v]} {set v [quote $v]} |
| 615 puts -nonewline $sep$v |
| 616 set sep , |
| 617 } |
| 618 puts ");" |
| 619 } |
| 620 puts "COMMIT;" |
| 621 |
| 622 } err]} { |
| 623 puts "ERROR: $err" |
| 624 puts $errorInfo |
| 625 exit 1 |
| 626 } |
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