Gevel contrib module provides several functions useful for analyzing GiST and GIN index. [Online version] of this document (http://www.sai.msu.su/~megera/oddmuse/index.cgi/Gevel) Caution: This module was designed for advanced users of GIN, GiST and SP-GiST indices ! Authors * Oleg Bartunov <oleg@sai.msu.su>, Moscow, Moscow University, Russia * Teodor Sigaev <teodor@sigaev.ru>, Moscow, Moscow University, Russia * Daria Lepikhova <d.lepikhova@postgrespro.ru>, Postgres Pro License Stable version, included into PostgreSQL distribution, released under BSD license. Development version, available from this site, released under the GNU General Public License, version 2 (June 1991) Install gevel module (requires 8.1+ version): % cd PGSQLSRC/contrib % tar xzvf gevel.tar.gz % make % make install % make installcheck % psql regression < gevel.sql * gist_stat(INDEXNAME) - show some statistics about GiST tree regression=# select gist_stat('pix'); Number of levels: 2 Number of pages: 30 Number of leaf pages: 29 Number of tuples: 3129 Number of leaf tuples: 3100 Total size of tuples: 137676 bytes Total size of leaf tuples: 136400 bytes Total size of index: 245760 bytes * gist_tree(INDEXNAME[,MAXLEVEL]) - show GiST tree up to MAXLEVEL regression=# select gist_tree('pix',0); 0(l:0) blk: 0 numTuple: 29 free: 6888b(15.63%) Designation (from left to right): o 0 - page number o (l:0) - tree level o blk: 0 - block number o numTuple: 29 - the number of tuples o free: 6888b - free space in bytes o (15.63%) - occupied space in percents * gist_tree(INDEXNAME) - show full GiST tree regression=# select gist_tree('pix'); 0(l:0) blk: 0 numTuple: 29 free: 6888b(15.63%) 1(l:1) blk: 13 numTuple: 180 free: 244b(97.01%) 2(l:1) blk: 11 numTuple: 175 free: 464b(94.32%) 3(l:1) blk: 2 numTuple: 101 free: 3720b(54.43%) 4(l:1) blk: 17 numTuple: 111 free: 3280b(59.82%) 5(l:1) blk: 18 numTuple: 101 free: 3720b(54.43%) 6(l:1) blk: 10 numTuple: 98 free: 3852b(52.82%) 7(l:1) blk: 19 numTuple: 111 free: 3280b(59.82%) 8(l:1) blk: 9 numTuple: 97 free: 3896b(52.28%) 9(l:1) blk: 20 numTuple: 104 free: 3588b(56.05%) 10(l:1) blk: 14 numTuple: 96 free: 3940b(51.74%) 11(l:1) blk: 21 numTuple: 106 free: 3500b(57.13%) 12(l:1) blk: 7 numTuple: 103 free: 3632b(55.51%) 13(l:1) blk: 1 numTuple: 101 free: 3720b(54.43%) 14(l:1) blk: 16 numTuple: 97 free: 3896b(52.28%) 15(l:1) blk: 24 numTuple: 103 free: 3632b(55.51%) 16(l:1) blk: 4 numTuple: 98 free: 3852b(52.82%) 17(l:1) blk: 25 numTuple: 98 free: 3852b(52.82%) 18(l:1) blk: 3 numTuple: 97 free: 3896b(52.28%) 19(l:1) blk: 26 numTuple: 96 free: 3940b(51.74%) 20(l:1) blk: 6 numTuple: 103 free: 3632b(55.51%) 21(l:1) blk: 8 numTuple: 162 free: 1036b(87.31%) 22(l:1) blk: 23 numTuple: 94 free: 4028b(50.66%) 23(l:1) blk: 12 numTuple: 82 free: 4556b(44.19%) 24(l:1) blk: 27 numTuple: 105 free: 3544b(56.59%) 25(l:1) blk: 5 numTuple: 90 free: 4204b(48.51%) 26(l:1) blk: 28 numTuple: 100 free: 3764b(53.90%) 27(l:1) blk: 22 numTuple: 101 free: 3720b(54.43%) 28(l:1) blk: 15 numTuple: 95 free: 3984b(51.20%) 29(l:1) blk: 29 numTuple: 95 free: 3984b(51.20%) * gist_print(INDEXNAME) - prints objects stored in GiST tree, works only if objects in index have textual representation (type_out functions should be implemented for given object type). It's known to work with R-tree GiST based index. Note, in example below, objects are of type box. # select * from gist_print('pix') as t(level int, valid bool, a box) where level =1; level | valid | a -------+-------+----------------------------- 1 | t | (37357,50073),(34242,357) 1 | t | (43499,49770),(40358,43) 1 | t | (31193,24679),(25047,12410) 1 | t | (31018,12142),(25083,6) 1 | t | (49944,25174),(43471,12802) 1 | t | (12577,49757),(6302,37534) 1 | t | (12528,37333),(6171,24861) 1 | t | (50027,49751),(46817,25462) 1 | t | (46870,49912),(43664,25722) 1 | t | (24855,25574),(12447,19263) 1 | t | (25054,19126),(12403,12796) 1 | t | (32737,49923),(31178,1038) 1 | t | (3184,24465),(15,81) 1 | t | (24951,49983),(12740,44000) 1 | t | (24919,43956),(12617,37901) 1 | t | (40387,49852),(37338,25217) 1 | t | (40325,24963),(37375,491) 1 | t | (24919,12698),(12654,6518) 1 | t | (25002,6338),(12350,51) 1 | t | (49985,12554),(43447,222) 1 | t | (25003,37769),(12552,25573) 1 | t | (34270,49382),(32763,594) 1 | t | (6205,50012),(3,37527) 1 | t | (6163,37358),(120,25034) 1 | t | (12343,24542),(9295,294) 1 | t | (9308,24151),(6234,620) 1 | t | (6230,24629),(3169,108) 1 | t | (31179,50040),(28113,25556) 1 | t | (28048,49694),(25000,25000) (29 rows) * spgist_stat(INDEXNAME) - show some statistics about SP-GiST tree # SELECT spgist_stat('spgist_idx'); spgist_stat ---------------------------------- totalPages: 21 + deletedPages: 0 + innerPages: 3 + leafPages: 18 + emptyPages: 1 + usedSpace: 121.27 kbytes+ freeSpace: 46.07 kbytes + fillRatio: 72.47% + leafTuples: 3669 + innerTuples: 20 + innerAllTheSame: 0 + leafPlaceholders: 569 + innerPlaceholders: 0 + leafRedirects: 0 + innerRedirects: 0 * spgist_print(INDEXNAME) - prints objects stored in GiST tree, works only if objects in index have textual representation (type_out functions should be implemented for given object type). Note 1. in example below we used quad_point_ops which uses point for leaf and prefix value, but doesn't use node_label at all. Use type 'int' as dummy type for prefix or/and node_label. Note 2 quad_point_ops: prefix point, node_label int, leaf_value point kd_point_ops: prefix float, node_label int, leaf_value point text_ops: prefix text, node_label char, leaf_value text # SELECT * FROM spgist_print('spgist_idx') as t ( tid tid, allthesame bool, node_n int, level int, tid_pointer tid, prefix point, node_label int, leaf_value point ) where level = 1; tid | allthesame | node_n | level | tid_pointer | prefix | node_label | leaf_value -------+------------+--------+-------+-------------+-------------------------------------+------------+------------ (1,1) | f | 0 | 1 | (5,4) | (24530.2070484581,23595.7092511013) | | (1,1) | f | 1 | 1 | (5,3) | (24530.2070484581,23595.7092511013) | | (1,1) | f | 2 | 1 | (5,2) | (24530.2070484581,23595.7092511013) | | (1,1) | f | 3 | 1 | (5,1) | (24530.2070484581,23595.7092511013) | | * gin_stat(INDEXNAME) prints estimated counts for each indexed values Note: since 8.4 gin_stat function has gin_stat(INDEXNAME, COLNUMBER) prototype, single-argument function will return result for a first column of index # SELECT * FROM gin_stat('gin_idx') as t(value int, nrow int) where nrow > 250; value | nrow -------+------ 31 | 254 47 | 251 52 | 257 59 | 259 (4 rows) * bigint gin_count_estimate(INDEXNAME, TSQUERY) outputs number of indexed rows matched query. It doesn't touch heap at all. # select gin_count_estimate('qq', 'star'); gin_count_estimate -------------------- 790 (1 row) * text gin_statpage(INDEXNAME) Prints various stat about index internals. # select gin_statpage('gin_idx'); gin_statpage ------------------------------ totalPages: 32 + dataPages: 1 + dataInnerPages: 0 + dataLeafPages: 1 + dataInnerFreeSpace: 0 + dataLeafFreeSpace: 4454 + dataInnerTuplesCount: 0 + dataLeafIptrsCount: 3600 + entryPages: 31 + entryInnerPages: 21 + entryLeafPages: 10 + entryInnerFreeSpace: 15160+ entryLeafFreeSpace: 32788+ entryInnerTuplesCount: 7810 + entryLeafTuplesCount: 305 + entryPostingSize: 42122+ entryPostingCount: 96759+ entryAttrSize: 64924+ * btree_stat(INDEXNAME) - show some statistics about btree index # SELECT btree_stat('btree_idx'); btree_stat ----------------------------------------- Number of levels: 2 + Number of pages: 75 + Number of leaf pages: 74 + Number of tuples: 11047 + Number of invalid tuples: 0 + Number of leaf tuples: 10973 + Total size of tuples: 547824 bytes+ Total size of leaf tuples: 543948 bytes+ Total size of index: 614400 bytes+ (1 row) * btree_tree(INDEXNAME[, MAXLEVEL]) - show btree elements from root up to MAXLEVEL # SELECT btree_tree('btree_idx'); btree_tree --------------------------------- lvl: 0, blk: 3, numTuples: 74 + lvl: 1, blk: 1, numTuples: 139 + lvl: 1, blk: 2, numTuples: 139 + lvl: 1, blk: 4, numTuples: 139 + lvl: 1, blk: 5, numTuples: 136 + lvl: 1, blk: 6, numTuples: 141 + lvl: 1, blk: 7, numTuples: 139 + lvl: 1, blk: 8, numTuples: 140 + lvl: 1, blk: 9, numTuples: 136 + lvl: 1, blk: 10, numTuples: 140+ lvl: 1, blk: 11, numTuples: 138+ lvl: 1, blk: 12, numTuples: 143+ lvl: 1, blk: 13, numTuples: 137+ lvl: 1, blk: 14, numTuples: 138+ lvl: 1, blk: 15, numTuples: 140+ lvl: 1, blk: 16, numTuples: 141+ lvl: 1, blk: 17, numTuples: 138+ lvl: 1, blk: 18, numTuples: 141+ lvl: 1, blk: 19, numTuples: 141+ lvl: 1, blk: 20, numTuples: 138+ lvl: 1, blk: 21, numTuples: 141+ lvl: 1, blk: 22, numTuples: 141+ lvl: 1, blk: 23, numTuples: 141+ lvl: 1, blk: 24, numTuples: 138+ lvl: 1, blk: 25, numTuples: 140+ lvl: 1, blk: 26, numTuples: 142+ lvl: 1, blk: 27, numTuples: 141+ lvl: 1, blk: 28, numTuples: 142+ lvl: 1, blk: 29, numTuples: 140+ lvl: 1, blk: 30, numTuples: 141+ lvl: 1, blk: 31, numTuples: 140+ lvl: 1, blk: 32, numTuples: 142+ lvl: 1, blk: 33, numTuples: 143+ lvl: 1, blk: 34, numTuples: 141+ lvl: 1, blk: 35, numTuples: 140+ lvl: 1, blk: 36, numTuples: 142+ lvl: 1, blk: 37, numTuples: 142+ lvl: 1, blk: 38, numTuples: 141+ lvl: 1, blk: 39, numTuples: 143+ lvl: 1, blk: 40, numTuples: 142+ lvl: 1, blk: 41, numTuples: 143+ lvl: 1, blk: 42, numTuples: 143+ lvl: 1, blk: 43, numTuples: 142+ lvl: 1, blk: 44, numTuples: 143+ lvl: 1, blk: 45, numTuples: 142+ lvl: 1, blk: 46, numTuples: 142+ lvl: 1, blk: 47, numTuples: 141+ lvl: 1, blk: 48, numTuples: 144+ lvl: 1, blk: 49, numTuples: 141+ lvl: 1, blk: 50, numTuples: 142+ lvl: 1, blk: 51, numTuples: 143+ lvl: 1, blk: 52, numTuples: 142+ lvl: 1, blk: 53, numTuples: 143+ lvl: 1, blk: 54, numTuples: 141+ lvl: 1, blk: 55, numTuples: 142+ lvl: 1, blk: 56, numTuples: 141+ lvl: 1, blk: 57, numTuples: 156+ lvl: 1, blk: 58, numTuples: 159+ lvl: 1, blk: 59, numTuples: 160+ lvl: 1, blk: 60, numTuples: 161+ lvl: 1, blk: 61, numTuples: 163+ lvl: 1, blk: 62, numTuples: 163+ lvl: 1, blk: 63, numTuples: 164+ lvl: 1, blk: 64, numTuples: 165+ lvl: 1, blk: 65, numTuples: 165+ lvl: 1, blk: 66, numTuples: 166+ lvl: 1, blk: 67, numTuples: 166+ lvl: 1, blk: 68, numTuples: 167+ lvl: 1, blk: 69, numTuples: 167+ lvl: 1, blk: 70, numTuples: 167+ lvl: 1, blk: 71, numTuples: 167+ lvl: 1, blk: 72, numTuples: 167+ lvl: 1, blk: 73, numTuples: 167+ lvl: 1, blk: 74, numTuples: 167+ lvl: 1, blk: 75, numTuples: 274+ (1 row) test1=# SELECT btree_tree('btree_idx', 0); btree_tree -------------------------------------- lvl: 0, coff: 0, blk: 3, numTuples: + (1 row) * btree_print() - print objects stored in btree works only if objects in index have textual representation (type_out functions should be implemented for given object type). # SELECT * FROM btree_print('btree_idx') as t(level int, val bool, a int[]) where level = 1; level | val | a -------+-----+------------------------- 1 | t | 1 | t | {1,1001} 1 | t | {3,52,31,62,98} 1 | t | {5,3,25} 1 | t | {6,70,15} 1 | t | {8,1} 1 | t | {9,96} 1 | t | {11,37,55} 1 | t | {12,96,72,23,83,56} 1 | t | {14,30,132,144,174} 1 | t | {15,87} 1 | t | {17,36,97,77} 1 | t | {18,171,283} 1 | t | {20,66,81} 1 | t | {22,31,38,77,21} 1 | t | {24,2,96} 1 | t | {25,218,241,241} 1 | t | {27,87,61,54,41} 1 | t | {29,53,109,128,129,195} 1 | t | {30,183,215} 1 | t | {32,41,4} 1 | t | {34,44,47,81,124,135} 1 | t | {35,1001} 1 | t | {37,81,85} 1 | t | {39,74,47,71,63,80} 1 | t | {41,60,71} 1 | t | {43,41,12,44,75,91} 1 | t | {45,26,61,15} 1 | t | {47,22,65} 1 | t | {49,16,63,56} 1 | t | {50,98,71,10} 1 | t | {52,53,81} 1 | t | {54,46,31,87,13,8} 1 | t | {55,1001} 1 | t | {57,99,66,93} 1 | t | {59,103,180,196} 1 | t | {61,63,59,62} 1 | t | {63,66} 1 | t | {65,30,39,82,89,34} 1 | t | {67,25} 1 | t | {69,8,75} 1 | t | {71,23,89} 1 | t | {73,24,81,58,22} 1 | t | {75,54,93,39,18} 1 | t | {77,31,77} 1 | t | {79,59} 1 | t | {81,61,86,96,47,67} 1 | t | {83,79,46,37,99} 1 | t | {85,72} 1 | t | {87,93,19} 1 | t | {89,161} 1 | t | {91,1001} 1 | t | {94,8} 1 | t | {96,33,86,28,19} 1 | t | {98,53,58,58,61} 1 | t | {100,80,23,24,17} 1 | t | {107,1001} 1 | t | {115,1001} 1 | t | {124,1001} 1 | t | {133,1001} 1 | t | {143,1001} 1 | t | {154,1000} 1 | t | {164,1001} 1 | t | {175,1001} 1 | t | {186,1001} 1 | t | {198,1001} 1 | t | {210,1001} 1 | t | {222,1001} 1 | t | {235,1001} 1 | t | {248,266} 1 | t | {260,1001} 1 | t | {273,1001} 1 | t | {285,1001} 1 | t | {298,1001} (74 rows) * brin_stat(INDEXNAME) - show some statistics about brin index # SELECT brin_stat('brin_idx'); brin_stat ------------------------------------ Number of revmap pages: 1 + Number of empty revmap pages: 0 + Number of regular pages: 1 + Number of tuples: 1 + Used space 56 bytes + Free space 8104 bytes+ (1 row) * brin_print() - print values for pages stored in brin index # SELECT brin_print('brin_idx') brin_print ------------------------------------------------------- Start block: 0; end block: 48; offset: 86, free: 3292+ (1 row)