From 8d30337566a94b5b66b00d1cdff01ec1203a53a2 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 4 Aug 2007 21:53:00 +0000 Subject: [PATCH] Fix up bad layout of some comments (probably pg_indent's fault), and improve grammar a tad. Per Greg Stark. --- src/backend/utils/adt/pg_lzcompress.c | 32 +++++++++++++++----------------- src/include/utils/pg_lzcompress.h | 20 +++++++++++--------- 2 files changed, 26 insertions(+), 26 deletions(-) diff --git a/src/backend/utils/adt/pg_lzcompress.c b/src/backend/utils/adt/pg_lzcompress.c index 085bc63e0d..f843232ba6 100644 --- a/src/backend/utils/adt/pg_lzcompress.c +++ b/src/backend/utils/adt/pg_lzcompress.c @@ -166,7 +166,7 @@ * * Copyright (c) 1999-2007, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/backend/utils/adt/pg_lzcompress.c,v 1.26 2007/04/06 04:21:43 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/pg_lzcompress.c,v 1.27 2007/08/04 21:53:00 tgl Exp $ * ---------- */ #include "postgres.h" @@ -211,29 +211,27 @@ typedef struct PGLZ_HistEntry * ---------- */ static const PGLZ_Strategy strategy_default_data = { - 256, /* Data chunks smaller 256 bytes are not - * compressed */ - 6144, /* Data chunks greater equal 6K force - * compression */ - /* except compressed result is greater uncompressed data */ - 20, /* Compression rates below 20% mean fallback - * to uncompressed */ - /* storage except compression is forced by previous parameter */ + 256, /* Data chunks less than 256 bytes are not + * compressed */ + 6144, /* Data chunks >= 6K force compression, unless + * compressed output is larger than input */ + 20, /* Below 6K, compression rates below 20% mean + * fallback to uncompressed */ 128, /* Stop history lookup if a match of 128 bytes - * is found */ + * is found */ 10 /* Lower good match size by 10% at every - * lookup loop iteration. */ + * lookup loop iteration */ }; const PGLZ_Strategy * const PGLZ_strategy_default = &strategy_default_data; static const PGLZ_Strategy strategy_always_data = { - 0, /* Chunks of any size are compressed */ - 0, /* */ - 0, /* We want to save at least one single byte */ + 0, /* Chunks of any size are compressed */ + 0, + 0, /* It's enough to save one single byte */ 128, /* Stop history lookup if a match of 128 bytes - * is found */ - 6 /* Look harder for a good match. */ + * is found */ + 6 /* Look harder for a good match */ }; const PGLZ_Strategy * const PGLZ_strategy_always = &strategy_always_data; @@ -511,7 +509,7 @@ pglz_compress(const char *source, int32 slen, PGLZ_Header *dest, * If the strategy forbids compression (at all or if source chunk too * small), fail. */ - if (strategy->match_size_good == 0 || + if (strategy->match_size_good <= 0 || slen < strategy->min_input_size) return false; diff --git a/src/include/utils/pg_lzcompress.h b/src/include/utils/pg_lzcompress.h index bed75d9af1..fdd9701ee0 100644 --- a/src/include/utils/pg_lzcompress.h +++ b/src/include/utils/pg_lzcompress.h @@ -3,7 +3,7 @@ * * Definitions for the builtin LZ compressor * - * $PostgreSQL: pgsql/src/include/utils/pg_lzcompress.h,v 1.14 2007/02/27 23:48:10 tgl Exp $ + * $PostgreSQL: pgsql/src/include/utils/pg_lzcompress.h,v 1.15 2007/08/04 21:53:00 tgl Exp $ * ---------- */ @@ -50,16 +50,18 @@ typedef struct PGLZ_Header * * min_input_size Minimum input data size to start compression. * - * force_input_size Input data size at which compressed storage is - * forced even if the compression rate drops below - * min_comp_rate (but not below 0). - * - * min_comp_rate Minimum compression rate (0-99%), the output - * must be smaller than the input. If that isn't + * force_input_size Minimum input data size to force compression + * even if the compression rate drops below + * min_comp_rate. But in any case the output + * must be smaller than the input. If that isn't * the case, the compressor will throw away its * output and copy the original, uncompressed data * to the output buffer. * + * min_comp_rate Minimum compression rate (0-99%) to require for + * inputs smaller than force_input_size. If not + * achieved, the output will be uncompressed. + * * match_size_good The initial GOOD match size when starting history * lookup. When looking up the history to find a * match that could be expressed as a tag, the @@ -70,8 +72,8 @@ typedef struct PGLZ_Header * longer the lookup takes, the smaller matches * are considered good. * - * match_size_drop The percentage, match_size_good is lowered - * at each history check. Allowed values are + * match_size_drop The percentage by which match_size_good is lowered + * after each history check. Allowed values are * 0 (no change until end) to 100 (only check * latest history entry at all). * ---------- -- 2.11.0